Download UDZBENIK ZA STUDENTE PTF - 2.god - Prehrambeno

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Obesity and the environment wikipedia, lookup

Freeganism wikipedia, lookup

Food studies wikipedia, lookup

Food coloring wikipedia, lookup

Human nutrition wikipedia, lookup

Food politics wikipedia, lookup

Food choice wikipedia, lookup

Nutrition wikipedia, lookup

Transcript
JOSIP JURAJ STROSMAYER UNIVERSITY
FACULTY OF FOOD TECHNOLOGY
OSIJEK
Lidija Obad
ENGLISH IN FOOD
TECHNOLOGY II
OSIJEK 2010.
Izdavač
Sveučilište Josipa Jurja Strossmayera u Osijeku
Prehrambeno-tehnološki fakultet Osijek
Recenzenti
Dr.sc. Žaneta Ugarčić-Hardi red.prof.
Prehrambeno-tehnološki fakultet, Osijek
Dr.sc. Marija Omazić izv.prof.
Filozofski fakultet, Osijek
Lektura
Emily Catherine Drača, prof.
Tisak
Grafika Osijek
PREFACE
This textbook is intended for the second year students of food
technology. It is composed of 18 units which are closely connected
with the field of study. The units are grouped into several sections
covering the field of microbiology, biochemistry, science on
nutrition, packaging and ecology. Furthermore, additional reading
is provided giving the opportunity to extend some of the topics
covered by the main units.
Each unit starts with a pre-reading task aimed at activating
students’ knowledge of the world they have already acquired and
stimulating them for reading. In addition to that, various exercises
for checking comprehension, either precede the text, giving a clear
task and focus on essential information, or follow the text making
the students refer to the text several times.
Students use various reading strategies in fulfilling the prescribed
tasks. They anticipate the content, read quickly to get the gist of the
text or immerse in detailed reading, use graphs, diagrams, look for
coherence and cohesion of the paragraphs or complete text.
Vocabulary is checked through synonyms, antonyms, translations,
collocations, word formation, and word families. Grammar is
checked via sentence formation or in specific grammar tasks.
Some exercises require of students active involvement in
discussions and debates.
At the end of the textbook there is an English- Croatian glossary
providing very specific terminology and general English terms as
well.
Lidija Obad MA
Contents
Units
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
Page
The World of Microbiology
Microbes
Structure and Function of Bacteria
Viruses
Using Microbes for Food Production
Biochemistry
Proteins
Enzymes
Carbohydrates
Fats, Lipids and Oils
Food Pyramids
Functional Foods
Nutrition, Brain Function and Behaviour
Alter Your Mood with Food
Chocolate: A Healthy Indulgence
Genetically Modified Organisms
Active and Intelligent Packaging
Water Pollution and Society
Glossary
Additional reading
References
1
6
9
14
18
22
26
31
35
39
44
50
56
62
67
72
77
84
90
95
115
UNIT 3
STRUCTURE AND FUNCTION OF BACTERIA
Activity 1 Pre-reading task
1. How do bacteria affect the human body?
2. What are the possible shapes of bacteria?
Activity 2 Text comprehension
Read the text to answer these questions:
1. Why do bacteria cause diseases?
2. What are the known cell shapes of bacteria?
3. Why is cell arrangement important?
4. What are the important parts of cell structure?
5. What is the role of the cell membrane?
Many of our most dreaded diseases are caused by bacteria, the most common group of
prokaryotes. The structure and biological activities of bacteria enable them to infect and
damage the body. Yet structures and functions unique to bacteria may be sensitive to
antibiotics that inhibit or destroy essential properties of prokaryotic cells. As a result, many
diseases that killed our ancestors are easily cured today.
line 5
Bacterial structures are difficult or impossible to distinguish using light microscopy. The
finer details of sub cellular structure are revealed best by high-resolution electron microscopy.
The general shape of individual bacterial cells is usually discernible with the bright field
microscope. Bacteria are differentiated into major categories based on microscopic
observations. These groupings reflect morphological properties such as 1) cell shape, 2) cell
size, 3) staining characteristics, 4) the manner in which similar cells are arranged.
line 11
Cell shape and arrangement
Most bacteria have a defined shape that falls into one of three morphological categories: 1)
spherical cocci (singular coccus), 2) rod-shaped bacilli (singular bacillus), 3) spiral organisms.
In addition, some bacteria are filamentous; they tend to form long strands composed of many
cells. In these cases, an occasional cell may be seen after it breaks away from a longer
filament. A few bacteria change their shapes and are called pleomorphic (pleo/mor;
morph/form).
line 18
A coccus is a spherical organism normally ranging between 0.4 and 2 um in diameter.
Cocci generally appear in groups formed by the incomplete separation of cells during the
reproductive process. The arrangement of the cells in the group is often indicative of an
organism’s identity. Although cell arrangement can give some clue as to the identity of an
organism, under certain conditions bacteria fail to grow in their characteristic patterns.
line 23
Bacilli are rod-shaped organisms usually ranging between 1 and 10 um in length. Some are
characteristically long and slender. Others are short and stumpy; they appear ovoid and are
referred to as coccobacilli. Some bacilli are curved into a form resembling a comma. These
cells are called vibrios, as in vibrio cholera, a pathogen that causes fatal gastrointestinal
disease. Some bacteria are flat rectangular boxes with perfectly, straight edges.
line 28
9
Spiral organisms are less common than cocci or bacilli and include the agent of syphilis.
They are divided into two groups, spirilla and spirochetes. These two groups of microbes are
very similar in shape but spirochetes are flexible whereas spirilla are rigid.
line 31
Cell structure
Although more than 1500 species of bacteria have been described, only about 100 are
primarily human pathogens. The factors contributing to many biological activities, including
their ability to initiate or promote disease, are often directly related to the exposed surface
structures and appendages of the bacterial cell.
line 36
In all cells cytoplasmic contents are separated from the environment by the cell membrane.
In addition, almost all prokaryotic cells are surrounded by at least one other structure, the cell
wall. In order to survive, the cell must remain separate from the environment. This separation
is accomplished by the cell membrane. Major disruptions in this barrier result in the spilling
of the cytoplasm from the cell and the death of the organism.
line 41
The cell membrane in bacteria is a phospholipid-protein bilayer similar to that present in
eykaryotic cells. The major difference is that there are no sterols in the cell membranes of
most prokaryotes. The cell membrane is the site of many functions that are accomplished by
specialized internal organelles in eukaryotes. These include:
line 45
1. transport of molecules in and out of the cell;
2. secretion of extra cellular enzymes;
3. respiration and photosynthesis;
4. regulation of reproduction;
5. cell wall synthesis.
line 50
Organisms must selectively regulate the transport of nutrients into and waste products out of
the cell. Usually each type of molecule requires specific receptors that can recognize it and
move it across the membrane. This is the function of many of the membrane proteins. The
presence or absence of the corresponding receptor proteins in the cell membrane determines
which molecules can be transported.
line 55
Before they can be transported across the cell membrane, larger food molecules must be
broken down outside the cell into smaller subunits. Such extra cellular digestion is mediated
by enzymes released from the bacteria into their fluid environment. Secretion of extra cellular
enzymes is another function of the cell membrane.
line 59
The functions accomplished by eukaryotic mitochondria (energy generation) and
chloroplasts (photosynthesis) are performed by the membrane in prokaryotes. The greater the
membrane area in the cell, the more respiration and photosynthesis can occur.
line 62
Production of bacterial progeny is partially regulated by the cell membrane. Specific
proteins in the membrane attach to the replicating DNA and separate the duplicated
chromosomes from each other. In addition, the cytoplasm of the daughter cells may be
physically separated from each other by formation of a septum (cross wall).
line 66
Molecules needed for constructing and repairing the cell wall are synthesized in the
cytoplasm and transported outside the cell. Specialized membrane proteins transport these
subunits across the cell membrane and assemble them into the growing cell wall.
line 69
Adapted from various sources
10
Activity 3 Look at Figure 6 and explain the cell shapes and arrangements. Add further
details by referring to the text.
Figure 6. Cell shapes and arrangements
whttp://www.zampwiki.com/?t=Bacillus_ (2009-12-13).
Activity 4 Explain the cell structure according to Figure 7 and expand the explanation
by referring to the text.
Figure7. Cell structure
www.macroevolution.net/prokaryotic.cell-structure.html(.2009-12-13).
11
Activity 5 Text comprehension
Fill in the table using the information from the text.
Cell type
Size
Shape
1-10 um
Spherical
Spiral
Activity 6 Text comprehension
Complete the sentences in the left-hand column with those in the right-hand column.
1.
2.
3.
4.
5.
Cell membrane damage results in
Molecule transport is done
Extra cellular digestion is
Molecules for cell wall reparation
More respiration occurs
a) are synthesized in the cytoplasm.
b) the cell death.
c) if the cell membrane is greater.
d) mediated by enzymes.
e) selectively.
1. ___ 2. ___ 3. ___ 4. ___ 5. ___
Activity 7 Vocabulary
Give the singular form of the following nouns:
Plural
Singular
Bacilli
_____________
Cocci
______________
Bacteria
______________
Activity 8 Vocabulary
Complete the following table:
Noun
Cell
Verb
to discern
Disruption
Secretion
to attach
to assemble
12
Adjective
Activity 9 Vocabulary
Complete the sentences using the words from activity 8 and make the necessary
changes:
1. Heavy snow has _______________ the transport system in the city.
2. All students ____________________ in the meeting room.
3. We have observed the protein ____________________ to the DNA.
4. It was not easy to ________________ patterns in these figures.
5. The ________________ arrangement indicates the organism’s identity.
6. If the _________________ of gastric juices is increased it may cause problems.
Activity 10 Grammar practice
The past participle can be used in various roles:
1. as an adjective
2. as a part of compound tenses
3. as a part of passive voice
4. as a replacement for a relative clause, e.g. cocci appear in groups formed by separation
( instead ….. in groups which are formed by separation)
Find three examples in the text for the following uses:
1. past participle as an adjective a)____________ b) ____________ c) _____________
2. past participle in passives a)____________ b)_____________
c)______________
3. past participle replacing a relative clause
a)_______________________________________________________________
b)________________________________________________________________
c)________________________________________________________________
13
UNIT 5
USING MICROBES FOR FOOD PRODUCTION
Activity 1 Pre-reading task
1. How were microbes used in the past in food production?
2. How are they used today in the food industry?
Activity 2 Read the text to answer these questions:
1 How long have people used microbes in food production?
2 What are the usual ways of using microbes in the food industry?
3. What is the condition for producing large quantities of by-products?
4. What food additives are produced from microbes and what is their effect on food?
5. Why are enzymes instrumental in food production?
Since the dawn of history, people have been putting microbes to work. Processes
discovered hundreds or thousands of years ago are still used today to produce bread, beer,
wine, cheese etc. Moreover, recent developments in molecular biology are expanding the
potential usefulness of microbes into new areas of industry, agriculture, medicine and food
production.
line 5
Microbes continue to be used in the food industry primarily in three ways.
1. Specific metabolic activities, usually fermentation reactions, generate organic compounds
that accumulate and transform some edible substances into foods with more desirable
characteristics. These altered properties usually help preserve foods and often enhance
flavour, texture or digestibility. Dairy products, breads, soy sauce, pickled vegetables,
alcoholic beverages and vinegar are produced by microbial fermentation.
line 11
2. Microbial cells, cultivated in large quantities, are used as protein supplements in feed for
livestock. Such single-cell proteins have also been suggested as alternative food resources for
humans.
line 13
3. Certain microbes produce metabolic by-products that have nutritional or flavour-enhancing
properties when added to foods and feeds. Enzymes isolated from microorganisms are also
instrumental in food production.
line 16
Food additives
Many vitamins, amino acids, nucleotides and enzymes that are commercially valuable to
the food industry are obtained in high concentrations from microbial cultures. The microbes’
metabolic control mechanisms must be circumvented before large quantities of the desired byproduct can be synthesized and harvested. Thus, it is desirable to obtain microbes that have
lost their sensitivity to metabolic regulation. For example, some mutants of Corynebacterium
glutamicum can produce more than 200 times the amount of lysine required for growth. The
amino acid extracted from these cultures is used for supplementing lysine-deficient plant
proteins in many animal feeds. More than 300,000 tons of glutamic acid, another amino acid
manufactured commercially by microbes, is used each year, primarily as the flavourenhancing salt, monosodium glutamate. Vitamin B12 is manufactured by commercial cultures
of propionibacteria in amounts 50,000 times that required for its growth. Other microbial
18
produced vitamins include riboflavin and precursors of vitamin A and C. Microbes also
produce huge quantities of nucleotides that have taste-enhancing properties.
line 30
Many enzymes instrumental in food production are also derived from microbes. Amylases
are used in the initial steps in several food fermentation processes to convert starch to
fermentable sugars. They are also used to partially predigest foods for young children, to
clarify fruit juices and in the manufacture of corn and chocolate syrups. The enzyme
invertase, obtained from saccharomyces cerevisiae, prevents the crystallization of sugars by
converting sucrose to the more soluble glucose and fructose. It is injected into some candies
to liquefy the centers. Other fungal enzymes, pectinases, dissolve pectin, a naturally occurring
thickening agent in ripe fruit. These enzymes are used to clarify juices and allow them to be
concentrated without solidifying, and to remove the gummy material around coffee beans
prior to roasting. Rennins are enzymes derived from moulds that are used to coagulate milk
for cheese production. Not long ago, these curdling enzymes were obtained solely from the
gastric juice of cattle and other animals.
line 42
Adapted from various sources
Figure 10 Microbes in food production
http://www.jgi.doe.gov/News/LABfoods.jpg (2010-02-15)
19
Activity 3 Text comprehension
Complete the sentences using the information from the text:
1. To obtain large quantities of by-products, it is important to ________________________.
2. Nucleotides are proved to have ________________________.
3. Microbial fermentation is used to produce _____________________________________.
4. Microbial produced vitamins include ________________________________________.
Activity 4 Text comprehension
Fill in the following table using the information from the text:
Type of enzyme
Usage
Amylases
Invertase
curdling enzyme in cheese production
thickening agent for juice clarification
Activity 5 Text organization
Put the following ideas in chronological order as they appear in the text:
______ condition for producing enzymes, vitamins, amino acids, in large quantities;
______ enzymes used in fruit juice production;
______ usage of microbes in the past
______ curdling agents used in the dairy industry;
______ usage of protein supplements in feed.
Activity 6 Vocabulary
Translate the following expressions and use them in your own sentences:
a) flavour-enhancing properties __________________________
___________________________________________________________________________
b) to circumvent control mechanism_____________________________
___________________________________________________________________________
c) thickening agent_________________________
___________________________________________________________________________
d) curdling enzymes__________________________
___________________________________________________________________________
e) lysine-deficient plant____________________
___________________________________________________________________________
20
Activity 7 Vocabulary
Complete the following table:
Noun
Verb
preserve
enhance
convert
liquefy
solidify
alter
Adjective
21
UNIT 7
PROTEINS
Activity 1 Pre-reading task
1. Why are proteins important for the human body?
2. What food is rich in proteins?
Activity 2 Reading task
Read the text to answer these questions:
1. How do proteins shape our life?
2. What are amino acids?
3. How are amino acids classified?
4. How are amino acids linked?
5. What is a helix?
6. What structure does collagen have?
7. What is a general belief about amino acids?
8. How can you define complete and incomplete protein food?
When Dutch chemist Johann Mulder (1802-1880) first classified protein in 1838 as the
prime substance of all life forms, he could scarcely guess how far-reaching his work would
become. From Mulder's early grasp of what he was seeing, protein has become recognized as
the essential life-substance of all living matter. In many ways, proteins act to shape our lives.
They act as structural units to build our bodies. As enzymes they change our food into
nutrients our cells can use. As antibodies, they shield us from disease. As peptide hormones,
they send messages that coordinate continuous body activity. Proteins do much more: they
guide our growth during childhood and then maintain our bodies throughout adulthood.
line8
The story of protein must begin with its unique building materials, the amino acids. A
major life-sustaining task of the human body is the constant building and rebuilding of all its
body tissues. There are 22 amino acids, all of which are important in the body's metabolism.
However, 10 of these 22 amino acids are designated as essential amino acids because the
body cannot synthesize them in sufficient quantity or at all. The most recently (1992) declared
essential amino acid is arginine named "molecule of the year" because it modulates the
bioavailability of nitrous oxide (NO), a powerful vasodilator in the blood vessels that inhibits
atherogenesis The remaining 12 amino acids are labeled "nonessential", as shown in Table 1.
line 16
The building units, amino acids, are used by the body to construct specific tissue proteins.
This process is made possible by the nature of amino acids, which enables them to form
peptide linkages and arrange themselves into peptide chains. The dual nature of amino acids –
the presence of a base (amino – NH2 ) group containing nitrogen on one end and an acid
(carboxyl – COOH) group on the other – enables them to join in the characteristic chain
structure of proteins. The end amino group of one amino acid joins the end carboxyl group of
another amino acid beside it. This characteristic joining of specific amino acids in a specific
sequence to make a specific protein is called a peptide bond. Long chains of amino acids
linked in this manner form proteins and are called polypeptides.
line 25
26
Table 1. Amino acids grouped as essential and nonessential
Essential amino acids
Arginine
Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Valine
Nonessential amino acids
Alanine
Aspargine
Aspartic acid
Cystine (cysteine)
Glutamic acid
Glutamine
Glycine
Hydroxylysine
Proline
Serine
Tyrosine
To make a compact structure, the long polypeptide chains coil or fold back on themselves
in a spiral shape called a helix. The proteins illustrate a huge diversity of compounds
produced by specific amino acid linkages. As a result, according to their varied specific
structures, tissue proteins perform many vital roles in body structure and metabolism. Here
are some examples. Myosin, the fibrous protein present in muscle fiber and shown in Figure
12, is composed of 153 amino acid long chains that coil and unfold on contraction and
relaxation. Shaped into long rods, these fibers end in two-headed bundles so that they can
change their shape and bend, making it possible to tighten and contract muscles and relax
them. Collagen, the structural protein, is made up of three separate polypeptide chains wound
around each other to produce a triple helix. Thus strengthened, the collagen is shaped into
long rods and bundled into stiff fibers because its job is to strengthen bone, cartilage, skin and
other body structures to maintain their form.
line 50
Figure 12. Myosine molecules
www.colorado.edu...IPHY3430-200/010muscles.htm (2010-02-10)
27
There are many persons shopping for amino acids and taking them singly or as multiple
supplements for a number of supposed improvements in health and fitness or as remedies for
health problems. They buy tryptophan for insomnia, lysine arginine for herpes. Two groups of
persons most vulnerable to such claims are athletes and elderly persons. The belief that
protein is a major energy source and builds muscle strength leads to the use of amino acid
supplements in an effort to attain this result. But carbohydrates and fats – not proteins – are
fuel substrates in muscle tissue, and excess protein only places excess metabolic burden on
the body. It is the exercise, not protein that increases and strengthens muscles. In the second
group, older adults seek to avoid health problems or relieve the pain and stress of chronic
illnesses of aging. The belief that amino acids will provide such magic elixirs is ill advised.
They are both an expensive burden on the income and ineffective source of needed protein
which is better found in an improved diet containing all the nutrients that work best together.
line 65
A common way of designating the quality of protein foods is whether they are complete
or incomplete in terms of the amounts of essential amino acids that they contain. Foods called
complete protein foods are those that contain all the essential amino acids in sufficient
quantity and ratio to meet the body's needs. These proteins are of animal origin: eggs, milk,
cheese and meat including poultry and fish. Another protein of animal origin, gelatin, does
not qualify because it lacks three essential amino acids- tryptophan, valine and isoleucine and
has only small amounts of leucine. Incomplete protein foods are those deficient in one or
more of the essential amino acids. These proteins are mostly of plant origin: grains, legumes,
nuts, and seeds. In a mixed diet, however, animal and plant proteins complement one another.
Even a mixture of plant proteins alone can provide adequate amounts of amino acids when
our basic use of various grains is expanded to include soy protein and other dried legume
(beans and peas) storage proteins. The value of variety in diets is therefore evident.
line 77
Adapted from Essentials of Nutrition and Diet Therapy by Sue Rodwell Williams
28
Activity 3 Text comprehension
Use the information from the text to complete these sentences:
1. Proteins are the prime substance of life because _________________________________
________________________________________________.
2. The dual nature of amino acids enables them to _________________________________
_______________________________________.
3. Essential amino acids are those that___________________________________________
_____________________________________ .
4. Collagen is shaped into long rods and stiff fibers because ________________
____________________________________________________________.
5. Fuel substrates in muscle tissue are
_________________________.
6. Incomplete protein food is described as _______________________________________
_____________________________________________ .
Activity 4 Text organization
Order the following subtitles chronologically as they appear in the text:
_____ Controversial attitudes towards amino acids
_____ Protein functions
_____ Types of protein food
_____ Amino acid classification and structure
Activity 5 Vocabulary
Translate the following expressions and use them in your own sentences:
a) life-sustaining task _________________________
___________________________________________________________________________
b) excess metabolic burden _________________________
___________________________________________________________________________
c) to relieve the pain_____________________________
___________________________________________________________________________
d) two-headed bundles___________________________
___________________________________________________________________________
Activity 6 Vocabulary
Give the opposite meaning of the following expressions:
chains coil
protein excess
muscle relaxation
to sustain life
________________
________________
________________
_________________
29
Activity 7 Sentence formation
Use the following expressions to make sentences.
1.designated them amino acids
essential are as the body cannot 10 because synthesize
__________________________________________________________________
2.childhood proteins is growth guided our by during
___________________________________________________________________________
3.is amino acids a sequence of called the joining in a peptide bond
___________________________________________________________________________.
4.wrong the magic provide amino acids elixir a is that it completely belief
___________________________________________________________________________
Activity 8 Past Participle
The past participle is often used to replace a relative clause e.g. Foods called complete
protein foods…(instead of Foods which are called complete…).
Find four examples in the text:
1. __________________________________________________________________
2. __________________________________________________________________
3. __________________________________________________________________
4. __________________________________________________________________
30
UNIT 8
ENZYMES
Activity 1 Anticipation
Skim the first sentence of each paragraph to anticipate the content of the text.
Activity 2 Reading task
Read the text to answer the questions:
1.
2.
3.
4.
5.
6.
What is the relationship between enzymes and chemical reactions?
What would happen to milk without enzymes?
Why is every reaction in a cell catalyzed by a different enzyme?
What is a co-enzyme?
When is the function of co-enzymes impaired?
How does environment influence enzymes?
Enzymes, the key proteins in the cell, determine in large part all of the properties of the
cell. They are responsible for the cell's ability to carry out its functions necessary for cell
multiplication. Enzymes catalyze (speed up) the large number of chemical reactions in the
cell. The conversion of one substance (the substrate) to another (the product) has been often
measured at varying intervals. In the absence of an enzyme, the substrate, the substance on
which the enzyme acts, is changed into a product so slowly that it is impossible to measure
the product's formation. However, an enzyme can convert substrate into a product in a short
time. For example, if milk is left at room temperature for several days, it sours as a result of
the action of bacterial enzymes on the substrate, lactose, to form the final product, lactic acid.
If the milk did not contain microorganisms that could break down lactose, the conversion of
lactose to lactic acid (souring) would still occur, but it would take many thousands of years.
A single enzyme molecule can convert as many as one million substrate molecules per second
to products. Reactions between molecules can occur rapidly in the absence of enzymes if the
temperature or pressure is raised to very high levels as can be accomplished in a chemical
laboratory. However, life cannot exist under these conditions. Thus, enzymes take the place of
heat and high pressure, allowing organisms to live at the relatively mild temperatures that
exist on and beneath the surface of the earth.
line 17
An enzyme functions first by combining, through weak bonding forces, with its substrate.
This interaction places a stress on the chemical bonds in the substrate. The interaction places a
stress on the chemical bonds in the substrate, which weakens them enough to break them and
then forms new bonds. Enzymes act in two steps. First, the substrate binds to a specific
portion of the enzyme, the active, or catalytic, site, to form an enzyme-substrate complex
(Figure 13). Second, the products of the reaction are released; leaving the enzyme unchanged
and free to combine with new substrate molecules. The arrangement of the enzyme and its
substrate is commonly referred to as a "lock-and-key" arrangement; the substrate is the key
and the enzyme the lock. Since the key must fit into the lock precisely, any particular enzyme
will act on only one or a limited number of substrates, all of which must have a similar shape
to fit the active site. This explains why almost every reaction in a cell is catalyzed by a
different enzyme. As a result, hundreds of different enzymes exist in the cell, but relatively
few molecules of each enzyme are needed, since they can be used over and over again.
line 30
31
Many enzymes cannot function unless they have another molecule, a coenzyme, bound to
them. Coenzymes are small nonprotein molecules such as nicotinamide adenine dinucleotide,
abbreviated NAD, which is more than twice the size of a nucleotide. All enzymes have the
same general function – to transfer molecules, atoms, or electrons from one molecule to
another. In some cases, this molecule is transferred when the coenzyme is still bound to the
enzyme; in other cases, the coenzyme separates from the enzyme in the transfer process.
There are many different coenzymes but the same coenzyme can bind to different enzymes, so
there fewer different coenzymes than there are enzymes. In some cases, the coenzyme is
bound very tightly to the enzyme so that it is essentially a part of the enzyme as it carries out
its function. In other cases, the coenzyme can readily separate from one enzyme and move to
another enzyme.
line 41
All coenzymes are synthesized from vitamins. If an organism lacks a vitamin, the
functions of all the different enzymes whose activity requires that coenzyme are impaired.
Thus, a single vitamin deficiency has serious consequences in animals. Besides, the enzymes
are influenced by the environment, which affects how rapidly cells multiply. The features of
the environment that are most important include temperature, pH, and salt concentration.
Most enzymes function best at low salt concentrations and at pH values slightly above 7. In
addition to being affected by extreme environmental conditions, the enzymes are inhibited by
a variety of compounds. Some compounds inhibit in a reversible manner; others in an
irreversible manner. Whether reversible or irreversible depends on whether the enzyme
functions after the inhibitor is removed. In reversible inhibition, the inhibitor binds to but
readily separates (dissociates) from the enzyme. In irreversible inhibition, the inhibitor binds
very strongly to the enzyme and does not dissociate readily. In both types, attachment occurs
to the active site of the enzyme, which prevents the substrate from binding to the site.
line 54
Adapted from Microbiology, A Human Perspective by Nester, Roberts, Pearsall, Anderson
Figure 13. Enzyme kinetics
http://hillarybio.blogspot.com/2008_09_01_archive.html (2010-02-24)
32
Activity 3 Text comprehension
Decide whether the following statements are true or false:
1. An enzyme takes a long time to convert substrate into a product.
2. The substrate binds to any part of the enzyme.
3. The substrate is the lock and the enzyme is the key.
4. Every reaction in a cell is catalyzed by a different enzyme.
5. The lack of vitamin impairs the functioning of enzymes.
6. Most enzymes function best at high salt concentrations.
T
T
T
T
T
T
F
F
F
F
F
F
Activity 4 Text cohesion
What is the role of the following connectors :
however (line 7)
thus (line 15)
since (line 26)
unless (31)
as (line39)
besides (line44)
____________________________________
____________________________________
____________________________________
____________________________________
____________________________________
____________________________________
Activity 5 Points of reference
What do the following words from the text refer to:
They (line 2)
refers to
These conditions (line 15) refer to
Its (line 18)
refers to
Them (line 19)
refers to
Others (line49)
refer to
___________________________
___________________________
__________________________
___________________________
___________________________
Activity 6 Vocabulary
Match the words from the left-hand column with those from the right-hand column to
make collocations:
1. bonding
2. catalytic
3. lock-and-key
4. transfer
5. vitamin
a) arrangement
b) process
c) deficiency
d) site
e) forces
1 ___ 2 ___ 3 ___ 4 ___ 5 ___
33
Activity 7 Sentence formation
Use the collocations from activity 6 to make sentences:
1. _____________________________________________________________
2. _____________________________________________________________
3. _____________________________________________________________
4. _____________________________________________________________
5. _____________________________________________________________
Activity 8 Conditional clauses
Complete these conditional clauses using the information from the text:
1. If your organism lacks a vitamin _____________________________________ .
2. Unless the enzymes had another molecule, a coenzyme , they
__________________________.
3. If the milk had not contained microorganisms ___________________________.
4. If it were an irreversible inhibition, ____________________________________.
34
UNIT 11
FOOD PYRAMIDS
Activity 1 Anticipate the content of the text by explaining the different food pyramids.
Figures 19 & 20 Food Pyramids
http://www.campshane.com/.../nutrition/pyramid.jpg (2010-02-24)
http://bellani.files.wordpress.com/2009/01/mypyramid.jpg (2010-02-24)
44
Activity 2 Reading task
Read the text to answer the following questions:
1. What was the purpose of the Basic Four?
2. What changes were introduced in the graphic of the late 1970s?
3. How was the message from the 1992 Food Pyramid formulated?
4. What are the differences between the eating patterns of the past and the present?
5. How does stress influence our digestion?
6. How does My Pyramid differ from the previous Food Pyramids?
A Brief History of Dietary Recommendations
First there was the "square meal", a four-cornered approach to meals that dated from 1943,
when the U.S. Department of Agriculture (USDA) announced the Basic Four to help citizens
achieve better nutrition during war shortages. The square meal included a meat portion, a
vegetable or fruit portion, a starch portion, and a milk portion, three times a day every day.
By the seventies Americans were no longer active and as they became fatter, scientists proved
links between rich food and heart disease. It was obvious that the square meal needed an
overhaul.
line 7
In the late 1970s, the USDA added another category to the Basic Four and put the culpritssweets, alcohol and fat- into it. Despite, or perhaps because of, the fifth element, incidences of
heart disease, diabetes, hypertension and stroke, and weight gain mounted. So during the
eighties the USDA decided to get graphic. The agency came up with an emblem designed to
signify what previous polygons could not – variety, proportion and moderation. The 1992
Food Pyramid stacked the food groups according to the proportions in which they should be
consumed, with grains occupying the wider base and sweets at the top. The message was, and
still is, make cereals, rice, pasta and bread the foundation of your diet. Consume plenty of
vegetables and fruits. Enjoy milk, cheese, yogurt, and other dairy products. Eat some meat
fish, poultry and legumes. Add a smattering of sweets, oils and fats. Unfortunately, the food
pyramid did not make U.S. citizens healthier. Today, two-thirds of Americans over the age of
twenty are overweight, and nearly one-third of adults are obese, according to the 1999-2000
National Health and Nutrition Examination.
line 20
Increasingly poor nutritional habits and lack of exercise undermined the Food Pyramid's
good intentions. The pattern of weight gain continued. Our bodies reflect what we put into
them, what we do, and where and how we live. Before the mass commercialization of food
products, people lived and ate closer to food sources. They ate whole foods. Today, there is
the drive to fill commercial demand at the least possible cost and increase shelf life and visual
appeal, whereas the quality of food deteriorates. Even though great advances have occurred in
food cultivation, food suppliers are delivering foods that were raised far from most people's
lives and often harvested weeks and months in advance of being sold. Lettuce harvested last
week does not supply as many nutrients as that picked today. Besides, the Food and Drug
Administration (FDA) approves irradiation of meat and poultry, fresh fruits and vegetables to
decrease or eliminate harmful bacteria. Irradiation reduces spoilage bacteria and inhibits
sprouting of vegetables and delays ripening. For example, irradiated strawberries stay
unspoiled up to three weeks, versus three to five days for untreated berries. Thereby,
nutritional value is decreased and food irradiation masks what may be unsanitary conditions
in food processing plants.
line 35
45
At the same time civilization is increasingly busy and food consumption patterns are
being transformed – and not necessarily in good direction. Many families rely on packaged
and processed food, heat-and-eat food, fast food. Even when we do eat at home, we tend to
eat prepared or partially prepared food. Only about a third of home-cooked meals are made
from scratch. As a result we are getting fewer nutrients, while our body remains genetically
programmed to thrive on the whole foods of our ancestors. As we live in very stressful times,
every time we are worried, sad or mad, our body reacts chemically. Like pollution, anxiety
destabilizes our systems by creating free radicals. Stress uses up extra nutrients and makes
existing nutrients more difficult to assimilate. In addition, stress often leads to overeating- and
overeating the wrong foods. Anxious people do not reach for carrots; they reach for chocolate,
chips and alcohol. Meanwhile, people are becoming more inert and less physically active.
line 46
Since consumers did not follow the advice of the old Food Pyramid, The USDA went to
work, with the goal of incorporating the latest science and making not a diet, but a set of
nutritional and educational tools. They aimed at a "food guidance system", that should be
much more motivating than the old food pyramid. The result , My Pyramid, is the tools
designed to encourage behavioral changes. While the old pyramid guided everybody to eat the
same proportion of fruits or vegetables, My Pyramid has a more personalized approach.
line52
For a quick estimate of what and how much you need to eat, you can simply enter your
age, sex and activity level in the My Pyramid Plan Box on the website. A page immediately
pops up telling you how many servings of each group you need to eat daily. The website
shows six coloured food-group segments: orange for grains, green for vegetables, red for fruit,
yellow for healthful oils, blue for milk, and purple for lean meat, poultry, seafood, beans and
eggs. Clicking on each one directs you into that specific food group and presents a cornucopia
of information on why each food group is vitally important to your health and weight. Finally,
the new stairway image on the pyramid reminds users to be more active, and a few clicks on
physical activity will show you how many calories various activities burn, and so you learn
the health benefits of exercise.
line 62
Adapted from What Should I Eat? A Complete Guide to the New Food Pyramid by Tershia d'
Elgin
46
Activity 3 Text organization
Skim the text to order these subtitles chronologically as they appear in the text:
______ My pyramid
_______ Eating patterns of the past and the present
_______ Present changes of food consumption patterns
_______ Historical overview of diet guidelines
Activity 4 Text comprehension
Fill in the following sentences using the information from the text:
1. In the 1990s the Food Pyramid advised citizens to eat ________________________
____________________________________________________________________.
2. Although the shelf life of products has increased today, food quality has deteriorated
because ______________________________________________________________
3. Irradiation is used today to ____________________________________________.
4. The present food consumption patterns have changed and people eat
____________________________________________________________________
5. Stress destabilizes our body because ____________________________________
________________________________________________________________.
Activity 5 Vocabulary
Find words in the text that mean the same as:
- economical use
___________________________
- food leftovers
___________________________
- satisfying meal
___________________________
- quality decline
___________________________
- revision or thorough examination ___________________________
- to arrange or pile up
___________________________
- a small scattered number or amount __________________________
- abundance
___________________________
- visual attraction
___________________________
- to produce an emblem
___________________________
47
Activity 6 Vocabulary
Translate the following expressions and use them in your own sentences:
a) to eat in moderation _________________________
__________________________________________________________________.
b) to undermine good intentions______________________
____________________________________________________________________.
c) sprouting of vegetables __________________________
____________________________________________________________________.
d) to delay fruit ripening __________________________
___________________________________________________________________.
Activity 7 Vocabulary
Analyze the Eating Pyramid in Figure 21 and fill in the missing words in the paragraph
below based on the information offered in the pyramid. The list of the missing words
contains more words than needed: insulin, nutrition, falling, grains,
health, quality, carbohydrates, exercise, pyramid, processed, developed.
The Healthy Eating Pyramid created by the __________ experts from the Harvard School of
Public Health is based on the best available scientific evidence about the links between diet
and ________. This new pyramid fixes fundamental flaws in the USDA ________ and gives
useful information to help people make better choices regarding their diet. This pyramid sits
on a foundation of daily __________ and weight control. The other bricks of the pyramid
include whole ___________ such as whole-wheat bread and brown rice which are digested
slowly, give energy and prevent type 2 diabetes. Whole grains are an excellent source of
_________________ mainly needed for energy. The body can't digest whole grains as quickly
as it can highly _________________ carbohydrates. This keeps blood sugar and insulin levels
from rising, then ________________ too quickly. Control of blood sugar and _____________
can keep hunger at bay and may prevent the development of type 2 diabetes.
48
Activity 8 Compare the Food Pyramid in Figure 19 with the Harvard Pyramid in Figure
21 and list several differences and similarities:
Similarities
1.
2.
3.
4.
5.
Differences
________________________________ 1. ________________________________
________________________________ 2. ________________________________
________________________________ 3._________________________________
_________________________________4. ________________________________
________________________________ 5. ________________________________
Figure 21 The Healthy Harvard Pyramid
http://www.hsph.harvard.edu/nutritionsource/images/H.(2010-02-24)
Activity 9. Read the following paragraph and pose four questions to cover the essential
information. Give a suitable title to the paragraph.
The Healthy Eating Pyramid puts some fats near the base, indicating they are okay to eat.
Although this recommendation seems to go against conventional wisdom, it is exactly in line
with the evidence and with common eating habits. The average American gets one-third or
more of his or her daily calories from fats, so placing them near the foundation of the pyramid
makes sense. Note, though, that it specifically mentions healthy fats and oils, not all types of
fats. Good sources of healthy unsaturated fats include olive, canola, soy, corn, sunflower and
other vegetable oils, trans-fat free margarines, nuts seeds and fatty fish such as salmon.
49
UNIT 12
FUNCTIONAL FOODS
Activity 1 Anticipation
Skim the first sentence of each paragraph and try to give the definition of functional
food.
Activity 2 Reading task
Read the text to answer the following questions:
1.Why is functional food important in our diet?
2. How do consumers react to functional food?
3. What is found in whole foods?
4. What effect does dietary fiber have on human health?
5. Are phytosterols good for health? Why?
Functional foods are any foods, modified foods, or food ingredients that provide
structural, functional, or health benefits, promoting optimal health, longevity and quality of
life. In short, functional foods are food products that provide specific health benefits beyond
the traditional nutrients they contain. Terms used to describe functional foods include fitness,
hypernutritional, super foods, as well as foodiceuticals and nutraceuticals.
line 5
The reason driving consumer interest in functional food includes increasing stamina
and vigor to meet the stresses of modern lifestyles, offsetting unhealthy diet habits, body
weight control ( nearly 50% of the population in many industrialized countries is overweight),
prevention of degenerative diseases (heart disease, stroke, cancer), counteracting the effects of
lack of exercise, and maintaining youthfulness. Market studies provide evidence consumers
are increasingly aware of and knowledgeable about foods and ingredients and their health
benefits. The market potential in the USA for functional foods grew from $11 to $ 20.5 billion
between 1995 and 2001 with an annual growth rate of 10.9%.
line 13
The concept of whole foods should be emphasized rather than fortification of less
nutritious foods with purified functional compounds, because whole grains and minimally
processed fruits and vegetables are often a better source of functional ingredients and are
generally multifunctional. In addition, whole foods may contain several functional
ingredients, as well as health-promoting components, that have not yet been identified. In line
with the concept that whole foods provide more benefits, many nutritionists believe that the
base of the USDA Food Guide Pyramid should include 6-11 servings of foods from whole
grain products, rather than listing breads, cereals, rice and pastas – all foods from grains that
may be from whole- or refined-grain fractions.
line 22
The functional ingredients discussed in this overview emphasize that cereal grains,
fruits, vegetables and other edible plant parts should be included in our daily diets. Cereal
products will play a major role in the development and marketing of functional foods. In
addition, cereals can be a source of ingredients with added health benefits, and cereal products
can serve as a vehicle for delivering functional ingredients from other sources. line 27
50
Functional compounds
Dietary Fiber
Dietary fiber produces a feeling of satiety and provides chewing resistance. It also
contributes to increased volume of consumed food. Cereal grains and grain properties of
cereal fibers have been extensively investigated. Cereal fractions with reported health benefits
resulting from the lowering of cholesterol and triglycerides include oat products (bran, rolled
oats), rice products (bran, bran oil), barley products and corn fiber oil.
line 34
Fructooligosaccharides
Wheat, barley, rye, garlic onion, chicory, leek, artichoke and banana are all sources of
fructooligosaccharides. They belong to a class of compounds that includes fructans and inulin.
Fructooligosaccharides have been reported to reduce serum cholesterol, blood pressure, toxic
metabolites, prevent cancer, constipation, diarrhea and improve liver function. line 39
Carotenoids
More than 600 carotenoids have been identified in various plants. Carotenoids are red,
orange and yellow pigments found in plant and algal sources. The most abundant carotenoid
is ß-carotene. As antioxidants, carotenoids react with free radicals, protective against
degenerative diseases (cancer, atherosclerosis) and premature aging.
line 44
Phytosterols
Sources of phytosterols include wheat germ oil, corn oil, corn, rice, bran, buckwheat,
sesame seed, coconut oil, and almonds. Phytosterols have been reported to reduce colon
cancer, decrease cholesterol absorption, lower LDL levels and reduce incidence of gallstones.
Flavonoids
More than 4000 flavonoids have been identified. Onion, broccoli, red wine and tea are
good sources of many flavonoids; unprocessed or minimally processed fresh ingredients and
foods provide more benefits from flavonoids than processed products. Green tea contains
nearly 70 mg of the flavonoids and has been shown to reduce the risk of gastric, esophageal
and colon cancer. Flavonoids found in soybean and soybean products (tofu, soy milk and
flour) have antibacterial and antifungal activity.
line55
Adapted from various sources
Figure 22. Functional food
http://www.aat-taa.eu/images/research/products.jpg (2010-02-24)
51
Figure 23. Functional food
http://www.purepossibilities.com/images/liquid_vitamins/ViBE_fruit_vegetables.jpg (2010-03-12)
Activity 3
List some advantages and disadvantages of functional and whole food.
Advantages of whole food
Disadvantages
a) ________________________
a) _______________________________
b) ________________________
b) _______________________________
c) ________________________
c) _______________________________
52
Advantages of functional food
Disadvantages
a) _________________________
a) ______________________________
b) _________________________
b) ______________________________
c)__________________________
c) ______________________________
Activity 4 Text comprehension
Fill in the following table:
Type of functional compound
Dietary fibre
Source
Benefit
corn oil, almonds
broccoli, red wine
rye, barley wheat
Carotenoids
Activity 5 Vocabulary
Translate the following expressions and use them in your own sentences:
a) nutraceuticals _________________________
________________________________________________________________.
b) stamina and vigor ______________________
________________________________________________________________:
c) to offset diet habits ____________________
________________________________________________________________.
d) food fortification ______________________
________________________________________________________________.
e) feeling of satiety ______________________
________________________________________________________________.
f) barley and oat products _________________
________________________________________________________________.
53
Activity 6
Scan the following table and underline functional components which reduce the risk of
cardiovascular diseases:
Figure 24. Functional food components
Examples of Functional Food Components
Functional components
Source
Potential benefits
Source: International Food Information Council
Carotenoids
Alpha-carotene/Beta-carotene Carrots, Fruits, Vegetables
Neutralize free radicals, which may cause damage to
cells
Lutein
Green vegetables
Reduce the risk of macular degeneration
Lycopene
Tomato products (ketchup,
sauces)
Reduce the risk of prostate cancer
Dietary Fibre
Insoluble Fibre
Wheat Bran
Reduce risk of breast or colon cancer
Beta-Glucan
Oats, barley
Reduce risk of cardiovascular disease. Protect against
heart disease and some cancers; lower LDL and total
cholesterol
Soluble Fibre
Psyllium
Reduce risk of cardiovascular disease. Protect against
heart disease and some cancers; lower LDL and total
cholesterol
Fatty Acids
Long chain omega-3 Fatty
Acids-DHA/EPA
Salmon and other fish oils
Reduce risk of cardiovascular disease. Improve mental,
visual functions
Conjugated Linoleic Acid
(CLA)
Cheese, meat products
Improve body composition. Decrease risk of certain
cancers
Anthocyanidins
Fruits
Neutralize free radicals; reduce risk of cancer
Catechins
Tea
Neutralize free radicals; reduce risk of cancer
Flavonones
Citrus
Neutralize free radicals; reduce risk of cancer
Flavones
Fruits/vegetables
Neutralize free radicals; reduce risk of cancer
Lignans
Flax, rye, vegetables
Prevention of cancer, renal failure
Tannins (proanthocyanidines)
Cranberries, cranberry
products, cocoa, chocolate
Improve urinary tract health. Reduce risk of
cardiovascular disease
Phenolics
Plant Sterols
Stanol ester
Corn, soy, wheat, wood oils
Lower blood cholesterol levels by inhibiting
cholesterol absorption
Prebiotics/Probiotics
Fructo-oligosaccharides
(FOS)
Jerusalem artichokes,
shallots, onion powder
Improve quality of intestinal microflora;
gastrointestinal health
Lactobacillus
Yogurt, Other dairy
Improve quality of intestinal microflora;
gastrointestinal health
Soy Phytoestrogens
Isoflavones: Daidzein
Genistein
Soybeans and soy-based
foods
Menopause symptoms, such as hot flashes protect
against heart disease and some cancers; lower LDL
and total cholesterol
http://www.4agr.gc.ca/AAFC-AAc/display-afficher.do(2010-02-22)
54
Activity 7 Vocabulary
Use each of these words to make a sentence.
NUTRIENT
NUTRITIONIST
NUTRITION
NUTRITION
NUTRITIOUS
NUTRITIVE
1. _____________________________________________________________________.
2. _____________________________________________________________________.
3. _____________________________________________________________________.
4. _____________________________________________________________________.
5. _____________________________________________________________________.
Activity 8 Vocabulary
Complete the following table:
Noun
Verb
Adjective
fortification
modified
Emphasize
Knowledge
Deliver
Activity 9 Vocabulary
Complete the sentences using the words from activity 8 and make necessary changes:
1.
2.
3.
4.
5.
I’d like to _____________ the importance of learning foreign languages.
This fruit drink is ______________ with vitamin C.
We usually get two _________________ of mail every day.
The proposals were unpopular and were accepted in a ____________ form.
He is very _______________ about English literature.
55
UNIT 16
GENETICALLY MODIFIED ORGANISMS
Activity 1 Pre-reading task
1. Is GM food our future?
2. What are the advantages or disadvantages of GM?
3. Would you accept GM food? Why?
Figure 29
http://www.repairstemcell.files.wordpress.com/2009/03/ge (2010-03-05)
By far the most common genetically modified (GM) organisms are crop plants. But the
technology has now been applied to almost all forms of life, from pets that glow under UV
light to bacteria which form HIV blocking “living condoms” and from pigs bearing spinach
genes to goats that produce spider silk.
line 4
GM tomatoes, as puree, first appeared on British supermarket shelves in 1996 (a different
fresh GM tomato first appeared in the US in 1994), but the consumer furor that surrounded
GM technology did not erupt until February 1999. This was because a controversial study
suggested that a few strains of GM potatoes might be toxic to laboratory rats. Those
experiments, subsequently criticized by other experts, were carried out in Scotland. line 9
What followed was a European anti-GM food campaign of near religious fervour.
Spearheaded in the UK by environmental groups and some newspapers, the campaign would
have far-reaching consequences. It culminated in an unofficial moratorium on the growth and
72
import of GM crops in Europe and led to a trade dispute with the US. GM crops are very rare
in Europe, strict labeling laws and regulations are in place for food and public opinion
towards the technology remains largely negative. GM produce has been taken up with far less
fuss in the US (where it does not have to be labeled), in Canada, China, Argentina, Australia
and elsewhere.
line 17
The human race has methodically improved crop plants through selective breeding for
many thousands of years, but genetic engineering allows that time-consuming process to be
accelerated and exotic traits from unrelated species to be introduced. But not everyone agrees
that it represents progress. The root of genetic engineering in crops lies in the 1997 discovery
that soil bug Agrobacterium tumefaciens can be used as a tool to inject potentially useful
genes into plants. With the help of that microbe and other gene-implantation technologies ,
geneticists have developed new crop types.
line 24
Most of these are modified to be pest, disease or herbicide resistant and include: soya,
wheat, oilseed rape (canola), cotton, sugar beet, walnuts, potatoes, peanuts, tomatoes, lettuce,
onion etc. The bacterial gene Bt is one of the most commonly inserted. It produces an
insecticidal toxin that is harmless to people. Supporters of GM technology argue that
engineered crops – such as vitamin A-boosted golden rice or protein-enhanced potatoes – can
improve nutrition, that drought- or salt-resistant varieties can flourish in poor conditions and
stave off world hunger and that insect-repelling crops protect the environment by minimizing
pesticide use. Other plants have been engineered to improve flavour, increase shelf-life,
increase hardiness and to be allergen-free. Geneticists have even created a no-tears onion to
banish culinary crying and novel caffeine-free plants.
line 33
Critics fear that what they call “Frankenstein foods” could have unforeseen adverse heart
effects on consumers producing toxic proteins (and allergens) or transferring antibiotic
resistance and other genes to human-gut bacteria to damaging effect. But there has been little
evidence to back up such risks so far. More plausible threats are that modified crops could
become insidious super weeds or that they could accidentally breed with wild plants or other
crops- genetically polluting the environment. This could be a potentially serious problem if
“pharm” crops, engineered to produce pharmaceutical drugs accidentally breed with food
varieties (or seeds become mixed up). Large numbers of field trials, carried out by the UK
government and others, reveal that gene transfer occurs. One 2002 study showed that
transgenes had spread from US to traditional maize varieties in Mexico. Studies also proved
that that pollen from FM plants can be carried on the wind for tens of kilometers. Many
experts agree that insect-repelling plants will also speed the evolution of insecticide-resistant
crops. Environmentalists also argue that growing GM crops affects farmland biodiversity.
Pickrell,John. Instant Expert GM Organisms, New Scientist, 2006.
http://www.newscientist.com/channel/life/gm-food/dn9921
73
Activity 2 Text comprehension
Decide if the following statements are true or false.
1. European attitude towards GM crops is mainly negative.
2. Sugar beet and walnuts are also genetically modified.
3. Gm crops are not popular in Australia and Argentina.
4. GM supporters claim that GM plants are good for environment.
5. Gene transfer from GM plants to wild plants can occur.
TF
TF
TF
TF
TF
Activity 3 Text comprehension
Complete the sentences using information from the text:
1. The negative attitude towards GM technology erupted in the USA in 1999 because
_______________________________________________________________.
2. Genetic engineering can accelerate ________________________________
_______________________________________________________________.
3. New crop types were developed due to _____________________________
_______________________________________________________________.
4. Our nutrition could be improved by new plant varieties like ____________
________________________________________________________________
5. GM food could have unpredicted effects on humans such as ____________
_______________________________________________________________.
Activity 4 Vocabulary
Translate the following expressions and use them in your own sentences:
1. to take up produce
____________________
_______________________________________________________________.
2. gene-implantation technology
______________________
_______________________________________________________________.
3. pest-resistant plant
_____________________
_______________________________________________________________.
74
4. plant breeding
___________________
_______________________________________________________________.
5. to stave off world hunger
_____________________
_______________________________________________________________.
6. vitamin A-boosted rice
____________________
_______________________________________________________________.
7. field trials
____________________
_______________________________________________________________.
8. insect-repelling crop
___________________
_______________________________________________________________.
Activity 5 Vocabulary
Use each of these words to make sentences.
GENETICS
GENETICIST
GENE
GENETICAL
1. ___________________________________________________________________.
2. ___________________________________________________________________.
3. ___________________________________________________________________.
4. ___________________________________________________________________.
75
Activity 6 Vocabulary
Match the words on the left side with those on the right side to make collocations:
1. selective
2. gene
3. genetic
4. no-tears
5. adverse
6. human-gut
7. herbicide
a) engineering
b) effect
c) bacteria
d) resistant
e) transfer
f) breeding
g) onion
Activity 7 Put the sentences in the correct order to make a coherent paragraph.
_____ These “superweeds” would then be herbicide tolerant as well.
_____ The possibility of interbreeding is shown by the defense of farmers against
lawsuits filed by Monsanto.
_____ Other introduced genes may cross over into non-modified crops planted next to
GM crops.
_____ The company has filed patent infringement lawsuits against farmers who may
have harvested GM crops.
______ Another concern is that crop plants engineered for herbicide tolerance and weeds
will cross-breed, resulting in the transfer of the herbicide resistance genes from the crops
into the weeds.
______ Monsanto claims that the farmers obtained Monsanto-licensed GM seeds from an
unknown source and did not pay royalties to Monsanto.
Activity 8 Put the following words in the correct order to make sentences.
1. GM Europe was crops in import the stopped of.
____________________________________________________________.
2. were plants shelf-life and improve many flavour engineered to.
_____________________________________________________________.
3. could crops plants environment modified breed other in accidentally with the
_____________________________________________________________.
76
UNIT 18
WATER POLLUTION AND SOCIETY
Activity 1 Pre-reading task
1. How can water be polluted?
2. What are the results of pollution?
3. What can we do to prevent further pollution?
Activity 2 Reading task
Read the text to answer these questions:
1.
2.
3.
4.
5.
How is the growth of aquatic plants and algae stimulated?
What is eutrophication?
When is fish respiration impaired?
How do chemical pollutants enter waterways?
Why is an excessive growth of algae dangerous?
WATER POLLUTION AND SOCIETY
By David Krantz and Brad Kifferstein
Figure 32 Water on Earth
http://www.umich.edu/~gs265/society/waterpollution.htm (2010-03-07)
Introduction
Comprising over 70% of the Earth's surface, water is undoubtedly the most precious natural
resource that exists on our planet. Without the seemingly invaluable compound comprised of
hydrogen and oxygen, life on Earth would be non-existent: it is essential for everything on our
planet to grow and prosper. Although we as humans recognize this fact, we disregard it by
84
polluting our rivers, lakes, and oceans. Subsequently, we are slowly but surely harming our
planet to the point where organisms are dying at a very alarming rate. In addition to innocent
organisms dying off, our drinking water has become greatly affected as is our ability to use
water for recreational purposes. In order to combat water pollution, we must understand the
problems and become part of the solution.
line 9
Causes of Pollution
Many causes of pollution including sewage and fertilizers contain nutrients such as nitrates
phosphates. In excess levels, nutrients over stimulate the growth of aquatic plants and algae.
Excessive growth of these types of organisms consequently clogs our waterways, use up
dissolved oxygen as they decompose, and block light to deeper waters. This, in turn, proves
harmful to aquatic organisms as it affects the respiration ability of fish and other
invertebrates that reside in water.
line 15
Pollution is also caused when silt and other suspended solids, such as soil, wash off ploughed
fields, construction and logging sites, urban areas and eroded river banks when it rains.
Under natural conditions, lakes, rivers, and other water bodies undergo Eutrophication, an
aging process that slowly fills in the water body with sediment and organic matter. When
these sediments enter various bodies of water, fish respiration becomes impaired, plant
productivity and water depth become reduced, and aquatic organisms and their environments
become suffocated. Pollution in the form of organic material enters waterways in many
different forms as sewage, as leaves and grass clippings, or as runoff from livestock feedlots
and pastures. When natural bacteria and protozoan in the water break down this organic
material, they begin to use up the oxygen dissolved in the water. Many types of fish and
bottom-dwelling animals cannot survive when levels of dissolved oxygen drop below two to
five parts per million. When this occurs, it kills aquatic organisms in large numbers which
leads to disruptions in the food chain.
line
Figure 33. Polluted river
http://www.umich.edu/~gs265/society/waterpollution.htm (2010-03-07)
85
Polluted Rivers in the United Kingdom
The pollution of rivers and streams with chemical contaminants has become one of the most
crucial environmental problems within the 20th century. Waterborne chemical pollution
entering rivers and streams
cause tremendous amounts of
destruction.
Pathogens are another type of
pollution that proves very
harmful. They can cause many
illnesses that range from
typhoid and dysentery to minor
respiratory and skin diseases.
Pathogens
include
such
organisms as bacteria, viruses,
and protozoan. These pollutants
enter
waterways
through
untreated sewage, storm drains,
septic tanks, runoff from farms,
and particularly boats that dump
sewage. Though microscopic,
these
pollutants
have
a
tremendous effect evidenced by
their ability to cause sickness.
Krantz,David;Kifferstein,Brad. Water Pollution and Society, 2010.
http://www.umich.edu/~gs265/society/waterpollution.htm (2010-03-07)
86
Activity 3 Text comprehension
Match the beginnings and endings of the sentences.
1. Life on Earth would not exist if
a) various dangerous diseases.
2. As humans pollute rivers and oceans
b) aquatic organisms will die.
3. An enormous growth of algae can
c) there were no hydrogen and oxygen.
4. If the level of dissolved oxygen drops d) refers to chemical contamination of rivers.
5. One of the key problems
e) our drinking water becomes greatly affected.
6. Pathogens as pollutants cause
f) clog the waterways
1 _____ 2 _____ 3 _____ 4______ 5_____ 6 _____
Activity 4 Vocabulary
Translate the following expressions and use them in your own sentences.
1. to clog waterways
______________________
_________________________________________________________________.
2. to wash off ploughed fields
______________________
_________________________________________________________________.
3. construction and logging site
______________________
_________________________________________________________________.
4. to suffocate aquatic organisms
______________________
__________________________________________________________________.
5. runoff from feedlots
______________________
__________________________________________________________________.
6. disruption of food chain
______________________
_________________________________________________________________.
Activity 5 Vocabulary
Complete the following table:
Noun
Verb
Prosper
Suffocate
Adjective
Contaminant
Drain
Reside
87
Activity 6 Vocabulary
Fill in the gaps with the words from exercise 5 and make necessary changes:
1.
2.
3.
4.
His family now _______________ in the south of France.
The report said that the victims ______________ in the fumes.
A country’s future _______________ depends upon the quality of education.
We ___________ the pond and filled it with fresh water.
Activity 7 Read the text and pose five questions covering essential information.
ADDITIONAL FORMS OF WATER POLLUTION
Three last forms of water pollution exist in the forms of petroleum, radioactive substances,
and heat. Petroleum often pollutes water bodies in the form of oil, resulting from oil spills.
The previously mentioned Exxon Valdez is an example of this type of water pollution. These
large-scale accidental discharges of petroleum are an important cause of pollution along shore
lines. Besides the super tankers, off-shore drilling operations contribute a large share of
pollution. One estimate is that one ton of oil is spilled for every million tons of oil
transported. This is equal to about 0.0001 percent. Radioactive substances are produced in the
form of waste from nuclear power plants, and from the industrial, medical, and scientific use
of radioactive materials. Specific forms of waste are uranium and thorium mining and
refining. The last form of water pollution is heat. Heat is a pollutant because increased
temperatures result in the deaths of many aquatic organisms. These decreases in temperatures
are caused when a discharge of cooling water by factories and power plants occurs.
1._________________________________________________________________________?
2._________________________________________________________________________?
3._________________________________________________________________________?
4._________________________________________________________________________?
5._________________________________________________________________________?
88
Activity 8 Read the text and complete with these words: impact, spread, coastal,
drilling, coral, demonstrators.
Figure 34. Greenpeace movement
http://www.umich.edu/~gs265/society/waterpollution.htm (2010-03-07)
Demonstrators Protest Drilling
Oil pollution is a growing problem, particularly devastating to_________ wildlife. Small
quantities of oil ____________ rapidly across long distances to form deadly oil slicks. In this
picture, ______________ with "oil-covered" plastic animals protest a potential________
project in Key Largo, Florida. Whether or not accidental spills occur during the project, its
____________ on the delicate marine ecosystem of the __________ reefs could be
devastating.
Activity 9 Put these sentences in the correct order to make a coherent paragraph.
Oil Spill Clean-up
_____ Even small amounts spread rapidly across large areas of water.
_____ Tanker spills are an increasing environmental problem because once oil has spilled, it
is virtually impossible to completely remove or contain it.
_____ Workers use special nets to clean up a California beach after an oil tanker spill
_____ Attempts to chemically treat or sink the oil may further disrupt marine and beach
ecosystems.
______ Because oil and water do not mix, the oil floats on the water and then washes up on
broad expanses of shoreline.
89
ADDITIONAL READING
UNIT 1
CLASSIFYING WATER POLLUTION
The major sources of water pollution can be classified as municipal, industrial, and
agricultural. Municipal water pollution consists of waste water from homes and commercial
establishments. For many years, the main goal of treating municipal wastewater was simply to
reduce its content of suspended solids, oxygen-demanding materials, dissolved inorganic
compounds, and harmful bacteria. In recent years, however, more stress has been placed on
improving means of disposal of the solid residues from the municipal treatment processes.
The basic methods of treating municipal wastewater fall into three stages: primary treatment,
including grit removal, screening, grinding, and sedimentation; secondary treatment, which
entails oxidation of dissolved organic matter by means of using biologically active sludge,
which is then filtered off; and tertiary treatment, in which advanced biological methods of
nitrogen removal and chemical and physical methods such as granular filtration and activated
carbon absorption are employed. The handling and disposal of solid residues can account for
25 to 50 percent of the capital and operational costs of a treatment plant. The characteristics of
industrial waste waters can differ considerably both within and among industries. The impact
of industrial discharges depends not only on their collective characteristics, such as
biochemical oxygen demand and the amount of suspended solids, but also on their content of
specific inorganic and organic substances. Three options are available in controlling industrial
wastewater. Control can take place at the point of generation in the plant; wastewater can be
pre-treated for discharge to municipal treatment sources; or wastewater can be treated
completely at the plant and either reused or discharged directly into receiving waters.
Wastewater Treatment
Raw sewage includes waste from sinks, toilets, and industrial processes. Treatment of the
sewage is required before it can be safely buried, used, or released back into local water
systems. In a treatment plant, the waste is passed through a series of screens, chambers, and
chemical processes to reduce its bulk and toxicity. The three general phases of treatment are
primary, secondary, and tertiary. During primary treatment, a large percentage of the
suspended solids and inorganic material is removed from the sewage. The focus of secondary
treatment is reducing organic material by accelerating natural biological processes. Tertiary
95
treatment is necessary when the water will be reused; 99 percent of solids are removed and
various chemical processes are used to ensure the water is as free from impurity as possible.
Agriculture, including commercial livestock and poultry farming, is the source of many
organic and inorganic pollutants in surface waters and groundwater. These contaminants
include both sediment from erosion cropland and compounds of phosphorus and nitrogen that
partly originate in animal wastes and commercial fertilizers. Animal wastes are high in
oxygen demanding material, nitrogen and phosphorus, and they often harbour pathogenic
organisms. Wastes from commercial feeders are contained and disposed of on land; their main
threat to natural waters, therefore, is from runoff and leaching. Control may involve settling
basins for liquids, limited biological treatment in aerobic or anaerobic lagoons, and a variety
of other methods.
Ground Water
Ninety-five percent of all fresh water on earth is ground water. Ground water is found in
natural rock formations. These formations, called aquifers, are a vital natural resource with
many uses. Nationally, 53% of the population
relies on ground water as a source of drinking
water. In rural areas this figure is even higher.
Eighty one percent of community water is
dependent on ground water. Although the 1992
Section 305(b) State Water Quality Reports
indicate that, overall, the Nation’s ground water
quality is good to excellent, many local areas have
experienced
significant
ground
water
contamination. Some examples are leaking
underground storage tanks and municipal landfills.
Legislation
Several forms of legislation have been passed in
recent decades to try to control water pollution. In
1970, the Clean Water Act provided 50 billion
dollars to cities and states to build wastewater facilities. This has helped control surface water
pollution from industrial and municipal sources throughout the United States. When congress
passed the Clean Water Act in 1972, states were given primary authority to set their own
standards for their water. In addition to these standards, the act required that all state
beneficial uses and their criteria must comply with the “fishable and swimmable” goals of the
act. This essentially means that state beneficial uses must be able to support aquatic life and
recreational use. Because it is impossible to test water for every type of disease-causing
organism, states usually look to identify indicator bacteria. One for example is a bacteria
known as faecal coliforms. Figure 1 shows the quality of water for each every state in the
United States, click on the US link). These indicator bacteria suggest that a certain selection
of water may be contaminated with untreated sewage and that other, more dangerous,
organisms are present. These legislations are an important part in the fight against water
pollution. They are useful in preventing Environmental catastrophes. The graph shows
reported pollution incidents since 1989-1994. If stronger legislations existed, perhaps these
events would never have occurred.
Krantz,David;Kifferstein, Brad. Water Pollution and Society, 2010.
http://www.umich.edu/~gs265/society/waterpollution.htm (2010-03-04)
96
UNIT 4
VEGETABLES AND FRUITS
Introduction
"Eat your fruits and vegetables" is one of the tried and true recommendations for a healthy
diet and for good reason. Eating plenty of vegetables and fruits can help you ward off heart
disease and stroke, control blood pressure, prevent some types of cancer, avoid a painful
intestinal ailment called diverticulitis, and guard against cataract and macular degeneration,
two common causes of vision loss.
What does "plenty" mean? More than most Americans consume. If you don't count
potatoes—which should be considered a starch rather than a vegetable—the average
American gets a total of just three servings of fruits and vegetables a day. The latest dietary
guidelines call for five to thirteen servings of fruits and vegetables a day (2½ to 6½ cups per
day), depending on one's caloric intake. (1) For a person who needs 2,000 calories a day to
maintain weight and health, this translates into nine servings, or 4½ cups per day (2 cups of
fruit and 2½ cups of vegetables).
Over the past 30 years or so, researchers have developed a solid base of science to back up
what generations of mothers preached (but didn't always practice themselves). Early on, fruits
and vegetables were acclaimed as cancer-fighting foods. In fact, the ubiquitous 5 A Day
message (now quietly changing to Fruits and Veggies: More Matters) seen in produce aisles,
magazine ads, and schools was supported in part by the National Cancer Institute. The latest
research, though, suggests that the biggest payoff from eating fruits and vegetables is for the
heart.
Figure 40. Fresh Fruits & Vegetables
http://www.img.allposters.com/6/LRG/20/2012/DUP6D00Z.jpg (2010-03-23)
102
Vegetables, Fruits, and Cardiovascular Disease
There is compelling evidence that a diet rich in fruits and vegetables can lower the risk of
heart disease and stroke.
The largest and longest study to date, done as part of the Harvard-based Nurses' Health Study
and Health Professionals Follow-up Study, included almost 110,000 men and women whose
health and dietary habits were followed for 14 years. The higher the average daily intake of
fruits and vegetables, the lower the chances of developing cardiovascular disease. Compared
with those in the lowest category of fruit and vegetable intake (less than 1.5 servings a day),
those who averaged 8 or more servings a day were 30 percent less likely to have had a heart
attack or stroke. (2) Although all fruits and vegetables likely contribute to this benefit, green
leafy vegetables such as lettuce, spinach, Swiss chard, and mustard greens; cruciferous
vegetables such as broccoli, cauliflower, cabbage, Brussels sprouts, bok choy, and kale; and
citrus fruits such as oranges, lemons, limes, and grapefruit (and their juices) make important
contributions. (2)
When researchers combined findings from the Harvard studies with several other long-term
studies in the U.S. and Europe, and looked at coronary heart disease and stroke separately,
they found a similar protective effect: Individuals who ate more than 5 servings of fruits and
vegetables per had roughly a 20 percent lower risk of coronary heart disease (3) and stroke,
(4) compared with individuals who ate less than 3 servings per day.
Vegetables, Fruits, and Blood Pressure
High blood pressure is a primary risk factor for heart disease and stroke. As such, it's a
condition that is important to control. Diet can be a very effective tool for lowering blood
pressure. One of the most convincing associations between diet and blood pressure was found
in the Dietary Approaches to Stop Hypertension (DASH) study. (5)
This trial examined the effect on blood pressure of a diet that was rich in fruits, vegetables,
and low-fat dairy products and that restricted the amount of saturated and total fat. The
researchers found that people with high blood pressure who followed this diet reduced their
systolic blood pressure (the upper number of a blood pressure reading) by about 11 mm Hg
and their diastolic blood pressure (the lower number) by almost 6 mm Hg—as much as
medications can achieve.
More recently, a randomized trial known as the Optimal Macronutrient Intake Trial for Heart
Health (Omni Heart) showed that this fruit and vegetable-rich diet lowered blood pressure
even more when some of the carbohydrate was replaced with healthy unsaturated fat or
protein. (6)
Vegetables, Fruits, and Cancer
Numerous early studies revealed what appeared to be a strong link between eating fruits and
vegetables and protection against cancer. But because many of these were case-control
studies, where people who already have a certain health outcome (cases) are compared to
people who do not have that outcome (controls), it is possible that the results may have been
skewed by problems inherent in these types of studies; people with illnesses, for example,
often recall past behaviour differently from those without illness, which can lead to potential
inaccuracy in the information that they provide to study investigators.
Cohort studies, which follow large groups of initially healthy individuals for years, generally
provide more reliable information than case-control studies because they don't rely on
information from the past. And data from cohort studies have not consistently shown that a
diet rich in fruits and vegetables prevents cancer in general. For example, in the Nurses'
103
Health Study and the Health Professionals Follow-up Study, over a 14-year period, men and
women with the highest intake of fruits and vegetables (8+ servings a day) were just as likely
to have developed cancer as those who ate the fewest daily servings (under 1.5). (2)
A more likely possibility is that some types of fruits and vegetables may protect against
certain cancers. A massive report by the World Cancer Research Fund and the American
Institute for Cancer Research suggests that non-starchy vegetables—such as lettuce and other
leafy greens, broccoli, bok choy, cabbage, as well as garlic, onions, and the like—and fruits
"probably" protect against several types of cancers, including those of the mouth, throat, voice
box, esophagus, and stomach; fruit probably also protects against lung cancer. (7)
Specific components of fruits and vegetables may also be protective against cancer. For
example, a line of research stemming from a finding from the Health Professionals Follow-up
Study suggests that tomatoes may help protect men against prostate cancer, especially
aggressive forms of it. (8) One of the pigments that give tomatoes their red hue—lycopene—
could be involved in this protective effect. Although several studies other than the Health
Professionals study have also demonstrated a link between tomatoes or lycopene and prostate
cancer, others have not or have found only a weak connection. (9) Taken as a whole,
however, these studies suggest that increased consumption of tomato-based products
(especially cooked tomato products) and other lycopene-containing foods may reduce the
occurrence of prostate cancer. (7) Lycopene is one of several carotenoids (compounds that the
body can turn into vitamin A) found in brightly colored fruits and vegetables, and research
suggests that foods containing carotenoids may protect against lung, mouth, and throat cancer.
(7) But more research is needed before we know the exact relationship between fruits and
vegetables, carotenoids, and cancer.
Harvard School of Public Health. The Nutrition Source – Vegetables and Fruits, 2010.
http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/vegetables-fullstory/index.html (2010-03-10)
104
UNIT 5
SMART PACKAGING
Intelligent Packaging for Fresh Fruit and Vegetables
Fresh-cut produce continues to be one of the fastest growing segments of food retailing and
while conventional film packaging is suitable for lettuce and prepared salads, it cannot cope
with the high respiration rates of pre-cut vegetables and fruit, leading to early product
deterioration. In the USA, novel breatheable polymer films are already in commercial use for
fresh-cut vegetables and fruit. Landec Corporation supplies Intellipac packaging films that are
acrylic side-chain crystallisable polymers tailored to change phase reversibly at various
temperatures from 0-68 °C. As the side-chain components melt, gas permeation increases
dramatically, and by further tailoring the package and materials of construction, it is possible
to fine tune the carbon dioxide to oxygen permeation ratios for particular products. The final
package is ‘smart’ because it automatically regulates oxygen ingress and carbon dioxide
egress by transpiration according to the prevailing temperature. In this way, an optimum
atmosphere is maintained around the product during storage and distribution, extending
freshness and allowing shipping of higher quality products to the consumer.
Self-Heating and Self-Chilling Packaging
Improved convenience is a value-added function that customers are likely to pay extra for
lifestyle change. Self-heating packages, for soup and coffee, for example, and self-cooling
containers for beer and soft drinks have been under active development for more than a
decade, but have yet to achieve commercial status. However, Crown Cork & Seal is
pioneering the development of a self-chilling beverage can in conjunction with Tempra
Technologies and development is nearing completion. The Crown/Tempra technology uses
the latent heat of evaporating water to produce the cooling effect. The water is bound in a gel
layer coating a separate container within the beverage can, and is in close thermal contact
with the beverage. The consumer twists the base of the can to open a valve, exposing the
water to the desiccant held in a separate, evacuated external chamber This initiates
evaporation of the water at room temperature. The unit has been designed to meet a target
specification set by major beverage customers cooling 300 ml of beverage in a 355 ml can by
16.7 °C in three minutes. This performance level has been achieved in laboratory tests and
working samples are currently undergoing focus group trials with customers.
Thermochromic Labelling
Give a self-heating or self-cooling container a sensor to tell the consumer it is at the correct
temperature and the package becomes ‘smart’ (such packaging is currently under
development). The most common use of a thermochromic ink dot indicates that the product is
at the correct serving temperature following refrigeration or microwave heating. Plastic
containers of pouring syrup for pancakes can be purchased in the USA that are labelled with a
thermochromic ink dot to indicate that the syrup is at the right temperature following
microwave heating. Similar examples can be found on supermarket shelves with beer bottle
labels that incorporate thermochromic-based designs to inform the consumer when a
refrigerated beer is cold enough to drink.
Packing,S. Smart Packaging-Intelligent Packaging for Food, 2003.
http://www.azom.com/Details.asp?ArticleID=2152 (2010-03-10)
105
UNIT 7
FOOD HYGIENE
As part of the revision of legislation on the hygiene of foodstuffs ("hygiene package"), this
Regulation focuses on defining the food safety objectives to be achieved, leaving the food
operators responsible for adopting the safety measures to be implemented in order to
guarantee food safety.
ACT
Regulation (EC) No 852/2004 of the European Parliament and of the Council of 29 April
2004 on the hygiene of foodstuffs.
SUMMARY
This revision of Community legislation concerns food hygiene rules as contained in Council
Directive 93/43/EEC, with a view to establishing a comprehensive and integrated policy
covering all food from the farm to the point of sale to the consumer.
Scope
This Regulation seeks to ensure the hygiene of foodstuffs at all stages of the production
process, from primary production up to and including sale to the final consumer. It does not
cover issues relating to nutrition or to the composition or quality of foodstuffs.This
Regulation applies to food businesses but not to the primary production of food for private
domestic use or the domestic preparation of foodstuffs for private consumption.
Definitions
'Food hygiene': the measures and conditions necessary to control hazards and ensure fitness
for human consumption of a foodstuff.
'Food safety': the assurance that food will not cause adverse health effects to the final
consumer when it is prepared and eaten.
'Primary production': the production, rearing or growing of primary products up to and
including harvesting, hunting, fishing, milking and all stages of animal production prior to
slaughter.
General and specific provisions
All food business operators shall ensure that all stages for which they are responsible, from
primary production up to and including the offering for sale or supply of foodstuffs to the
final consumer, are carried out in a hygienic way in accordance with this Regulation.
Food business operators carrying out primary production and certain associated activities
shall comply with the general hygiene provisions of part A of Annex I. Derogations may be
granted for small businesses, provided that they do not compromise achievement of the
Regulation's objectives.
These associated activities are:
• the transport, handling and storage of primary products at the place of
production, where their nature has not been substantially altered;
• the transport of live animals, where this is necessary;
107
•
transport, from the place of production to an establishment, of products
of plant origin, fishery products and wild game, where their nature has
not been substantially altered.
In addition, food business operators carrying out activities other than primary production shall
comply with the general hygiene provisions of Annex II.
This Annex sets out the hygiene requirements for:
• food premises, including outside areas and sites;
• transport conditions;
• equipment;
• food waste;
• water supply;
• personal hygiene of persons in contact with food;
• food;
• wrapping and packaging;
• heat treatment, which may be used to process certain foodstuffs;
• training of food workers.
Member States may adapt the requirements laid down in Annex II to accommodate the needs
of food businesses situated in regions suffering from special geographical constraints or
affected by supply difficulties which are serving the local market, or to take account of
traditional methods of production and the size of farms. The objectives of food hygiene shall
not however be compromised.
In addition, all food business operators shall comply with the provisions of Regulation (EC)
No 853/2004 on specific hygiene rules for food of animal origin and, where appropriate,
certain specific rules concerning microbiological criteria for foodstuffs, temperature control
and compliance with the cold chain, sampling and analysis.
The HACCP system
Food business operators (other than at the level of primary production) shall apply the
principles of the system of hazard analysis and critical control points (HACCP) introduced by
the Codex Alimentarius (code of international food standards drawn up by the United Nations
Food and Agriculture Organisation).
These principles prescribe a certain number of requirements to be met throughout the cycle of
production, processing and distribution in order to permit, via hazard analysis, identification
of the critical points which need to be kept under control in order to guarantee food safety:
• identify any hazards that must be prevented, eliminated or reduced to
acceptable levels;
• identify the critical control points at the step or steps at which control is
essential;
• establish critical limits beyond which intervention is necessary;
• establish and implement effective monitoring procedures at critical
control points;
• establish corrective actions when monitoring indicates that a critical
control point is not under control;
• implement own-check procedures to verify whether the measures
adopted are working effectively;
• keep records to demonstrate the effective application of these measures
and to facilitate official controls by the competent authority.
Guides to good practice and guides to the application of HACCP
108
Member States shall encourage the development of national guides to good practice by food
business operators, which shall include guidance on compliance with the general rules of
hygiene and the HACCP principles. Member States shall assess such national guides to ensure
that their contents are practicable, that they have been developed having regard to the general
principles of food hygiene of the Codex Alimentarius and that all interested parties have been
consulted. Those national guides deemed to comply with these requirements shall be
forwarded to the Commission.
Where a Member State or the Commission considers that there is a need for uniform
Community guides, the Commission shall consider the case for such guides. The Standing
Committees set up to assist the Commission shall ensure that the contents of these guides are
practicable, that they have been developed having regard to the general principles of food
hygiene of the Codex Alimentarius and of national guides, and that all interested parties have
been consulted.
Regulation (EC) No 852/2004 of the European Parliament and of the Council of 29 April
2004 on the hygiene of foodstuffs, 2010.
http://europa.eu/legislation_summaries/food_safety/veterinary_checks_and_food_hygiene/f84
001_en.htm (2010-03-01)
109
UNIT 8
CARBOHYDRATE METABOLISM
Many aspects of biochemistry and physiology have to do with the breakdown and synthesis of
simple sugars, oligosaccharides, and polysaccharides, and with the transport of sugars across
cell membranes and tissues. The breakdown or dissimilation of simple sugars, particularly
glucose, is one of the principal sources of energy for living organisms. The dissimilation may
be anaerobic, as in fermentations, or aerobic, that is, respiratory. In both types of metabolism,
the breakdown is accompanied by the formation of energy-rich bonds, chiefly the
pyrophosphate bond of the coenzyme adenosine triphosphate (ATP), which serves as a
coupling agent between different metabolic processes. In higher animals, glucose is the
carbohydrate constituent of blood, which carries it to the tissues of the body. In higher plants,
the disaccharide sucrose is often stored and transported by the tissues. Certain
polysaccharides, especially starch and glycogen, are stored as endogenous food reserves in the
cells of plants, animals, and microorganisms. Others, such as cellulose, chitin, and bacterial
polysaccharides, serve as structural components of cell walls. As constituents of plant and
animal tissues, various carbohydrates become available to those organisms which depend on
other living or dead organisms for their source of nutrients. Hence, all naturally occurring
carbohydrates can be dissimilated by some animals or microorganisms.
Certain carbohydrates cannot be used as nutrients by humans. For example, cellulose cannot
be digested by humans or other mammals and is a useful food only for those, such as the
ruminants, that harbour cellulose-decomposing microorganisms in their digestive tracts. The
principal dietary carbohydrates available to humans are the simple sugars glucose and
fructose, the disaccharides sucrose and lactose, and the polysaccharides glycogen and starch.
Lactose is the carbohydrate constituent of milk and hence one of the main sources of food
during infancy. The disaccharides and polysaccharides that cannot be absorbed directly from
the intestine are first digested and hydrolyzed by enzymes, glycosidases, secreted into the
alimentary canal. The simple sugars reach the intestine or are produced there through the
digestion of oligosaccharides. They are absorbed by the intestinal mucosa and transported
across the tissue into the bloodstream. This process involves the accumulation of sugar
against a concentration gradient and requires active metabolism of the mucosal tissue as a
source of energy. The sugars are absorbed from the blood by the liver and are stored there as
glycogen. The liver glycogen serves as a constant source of glucose in the bloodstream. The
mechanisms of transport of sugars across cell membranes and tissues are not yet understood,
but they appear to be highly specific for different sugars and to depend on enzymelike
components of the cells.
The degradation of monosaccharides may follow one of several types of metabolic pathways.
In the phosphorylative pathways, the sugar is first converted to a phosphate ester
(phosphorylated) in a reaction with ATP. The phosphorylated sugar is then split into smaller
units, either before or after oxidation. In the non-phosphorylative pathways, the sugar is
usually oxidized to the corresponding aldonic acid. This may subsequently be broken down
either with or without phosphorylation of the intermediate products. Among the principal
intermediates in carbohydrate metabolism are glyceraldehyde-3-phosphate and pyruvic acid.
The end products of metabolism depend on the organism and, to some extent, on the
environmental conditions. Besides cell material the products may include carbon dioxide
(CO2), alcohols, organic acids, and hydrogen gas. In the so-called complete oxidations, CO2 is
110
the only excreted end product. In incomplete oxidations, characteristic of the vinegar bacteria
and of certain fungi, oxidized end products such as gluconic, ketogluconic, citric, or fumaric
acids may accumulate. Organic end products are invariably found in fermentations. The
amount of biosynthesis and mechanical work that an organism can do at the expense of a
given amount of sugar is many times greater in respiration than in fermentation.
The principal phosphorylative pathway involved in fermentations is known as the glycolytic,
hexose diphosphate, or Embden-Meyerhof pathway (see illustration). This sequence of
reactions is the basis of the lactic acid fermentation of mammalian muscle and of the
alcoholic fermentation of yeast. For every molecule of glucose fermented through the
glycolytic sequence, two molecules of ATP are used for phosphorylation, while four are
produced. Thus, fermentation results in the net gain of two energy-rich phosphate bonds as
ATP at the expense of inorganic phosphate esterified. The excess ATP is converted back to
ADP and inorganic phosphate through coupled reactions useful to the organism, such as the
mechanical work done by the contraction of muscle or biosynthetic reactions associated with
growth.lycolysis in lactic acid fermentation
The oxidative or respiratory metabolism of sugars differs in several respects from
fermentative dissimilation. First, the oxidative steps, that is, the reoxidation of NADH, are
linked to the reduction of molecular oxygen. Second, the pyruvic acid produced through
glycolytic or other mechanisms is further oxidized, usually to CO2 and H2O. Third, in most
aerobic organisms, alternative pathways either supplement or completely replace the
glycolytic sequence of reactions for the oxidation of sugars. Where pyruvic acid appears as a
metabolic intermediate, it is generally oxidatively decarboxylated to yield CO2 and the twocarbon acetyl fragment which combines with coenzyme A. The acetyl group is then further
oxidized via the Krebs cycle. The principal alternative pathways by which sugars are
dissimilated involve the oxidation of glucose-6-phosphate to the lactone of 6phosphogluconic acid and are known as the hexose monophosphate pathways.
The metabolism of simple sugars other than glucose usually involves the conversion of the
sugar to one of the intermediates of the phosphorylative pathways described for glucose
metabolism. For example, fructose may be phosphorylated to fructose-6-phosphate, which
can then be degraded via the glycolytic pathway or converted to glucose-6-phosphate and
oxidized through the hexose monophosphate pathway.
The dissimilation and biosynthesis of the oligosaccharides are effected through the enzymatic
cleavage or formation of glycosidic bonds between simple monosaccharide constituents of the
complex carbohydrates. The principal types of enzyme which split or synthesize glycosidic
bonds are the hydrolases or glycosidases, phosphorylases, and transglycosylases. The
enzymes are generally highly specific with respect to the glycosidic portion, or moiety, and
the type of linkage of the substrates which they attack. The essential function of all three
types of enzymes is the transfer of the glycosyl moiety of the substrate to an appropriate
glycosyl acceptor. The phosphorylases catalyze the reversible phosphorolysis of certain
disaccharides, polysaccharides, and nucleosides by transferring the glycosyl moieties to
inorganic phosphate. The breakdown of glycogen and starch by the enzymes known as
amylophophorylases is an example of biologically important phosphorolytic reactions.
The Free Dictionary. Carbohydrate Metabolism, 2010.
http://encyclopedia2.thefreedictionary.com/Carbohydrate+metabolism (2010-03-23)
111