Download GCSE Revision Notes Food Technology

GCSE Revision Notes
Food Technology
© irevise.com 2014.
All revision notes have been produced by mockness ltd for irevise.com.
Email: [email protected]
Copyrighted material.
All rights reserved; no part of this publication may be reproduced, stored in a retrieval
system or transmitted, in any form or by any means, electronic, mechanical, photocopying,
recording, reprinting, or otherwise without either the prior written permission of
irevise.com or a license permitting copying in the United Kingdom issued by the copyright
licensing Agency.
1
Contents
Carbohydrates:........................................................................................................................................ 4
Sugars: ................................................................................................................................................. 4
Starch: ................................................................................................................................................. 5
Dietary Fibre/Non-Starch Polysaccharides (NSPs) .................................................................................. 5
Proteins ................................................................................................................................................... 6
Eggs ..................................................................................................................................................... 6
Fats and Oils ............................................................................................................................................ 7
Mono-Unsaturated Fats:..................................................................................................................... 8
Trans-Unsaturated Fats....................................................................................................................... 8
Essential Fatty Acids:........................................................................................................................... 8
Water ...................................................................................................................................................... 8
Vitamins .................................................................................................................................................. 9
Fat Soluble Vitamins ........................................................................................................................... 9
Water-Soluble Vitamins ...................................................................................................................... 9
Minerals ................................................................................................................................................ 10
Additives ............................................................................................................................................... 11
Acids and Alkali ..................................................................................................................................... 11
Food and Energy ................................................................................................................................... 12
Dietary guidelines -RDA .................................................................................................................... 13
Eatwell Plate ..................................................................................................................................... 13
Special Diets .......................................................................................................................................... 14
Health Problems and Diet ..................................................................................................................... 14
Religious Beliefs and Diet Restrictions .................................................................................................. 15
New Food Technologies ........................................................................................................................ 15
Food Contamination ............................................................................................................................. 15
Food Poisoning ...................................................................................................................................... 16
Cooking temperatures .......................................................................................................................... 17
Food Preservation ................................................................................................................................. 17
Labelling ................................................................................................................................................ 18
Food and Society ................................................................................................................................... 18
Environmental Issues ............................................................................................................................ 19
The 6Rs .................................................................................................................................................. 19
2
Packaging .............................................................................................................................................. 20
Packaging materials .......................................................................................................................... 20
Special Packaging .............................................................................................................................. 21
Environmental Effect of Packaging ....................................................................................................... 21
Cooking Terms .................................................................................................................................. 21
Production Methods ......................................................................................................................... 23
One-Off Production........................................................................................................................... 23
Batch Production .............................................................................................................................. 23
Mass Production ............................................................................................................................... 23
Continuous Flow ............................................................................................................................... 23
CAD, CAM and ICT ................................................................................................................................. 23
CAD (Computer Aided Design) .......................................................................................................... 23
CAM (Computer Aided Manufacturing) ............................................................................................ 23
ICT (Information and Communication Technology).......................................................................... 24
3
The human diet is made up of 5 essential groups:





Carbohydrates
Proteins
Fats and Oils
Vitamins
Minerals
Carbohydrates:
Sugars:
Monosaccharides
Single sugar molecules
Digested by cells, releasing energy quickly.
Sweet tasting, often used as sweetener and flavouring
Eg. Glucose and fructose in fruits
Disaccharides
Two sugar molecules bonded together
Digested quite quickly.
Found naturally in many foods, e.g. Lactose in milk, sucrose in sugar cane.
Sugars are broken down into glucose in the body and digested to release energy. However, the body
can also convert glucose into fats as storage. If the body needs more energy, these fats stores can be
converted back into glucose.
Too much sugar in the diet can lead to tooth decay, weight gain and diabetes.
Types of Sugars used in cooking:
Granulated Sugar (Sucrose)
Caster Sugar (Granulated Sugar in finer crystals)
Brown Sugar (Partially refined sucrose sugar
containing molasses byproduct)
Powdered/Icing Sugar (Finer crystals than Caster
sugar)
Uses of Sugars in cooking:
1.
2.
3.
4.
A sweetener in foods
A preservative in jams, preventing spoilage and contamination.
Used as energy source for fermentation in yeast to allow bread dough to rise.
Brown sugar can be used to add colour and flavour to pastries.
4
5. Can be heated and dehydrated to produce caramel
Starch:
Polysaccharide
Long chains of sugar molecules.
Digested slowly, releasing energy over a longer period of time.
E.g. Sugar in potatos
Uses of Starch in cooking:
1. Bulking: Starch molecules bind to water molecules, causing the starch to increase in mass.
E.g. when rice is boiled in water.
2. Gelatinisation: When starch is heated for too long in hot water (^80°C), the bonds between
molecules start to breakdown and reform differently, producing a gel.
3. Thickening: Gelatinisation can be used to thicken sauces by adding corn starch or flour and
heating.
Dietary Fibre/Non-Starch Polysaccharides (NSPs)








Complex polysaccharide molecules.
Found in fruit, vegetables, nuts, seeds and whole grains.
Can be soluble (Dissolve in water) or insoluble (Doesn’t dissolve in water).
Soluble fibre dissolves in water as it passes through the intestines, where it can be
metabolised by bacteria to produce important by-products.
Insoluble fibre absorbs water and provides bulking, helping food to move through your
digestive system. It is not metabolised as it travels through the intestines.
A diet rich in fibre is essential for maintaining health intestines, preventing constipation and
other bowel disorders.
Fibre can also decrease appetite and slow the digestion of sugars, helping to regulate blood
sugar levels, especially in people with diabetes.
However, as fibre works with water in the intestines, if not enough water is consumed with
food, dietary fibre can also cause constipation
5
Proteins
Proteins are vital molecules needed for growth and repair of cells.
They consist of chains of different amino acids. Your body breaks down these long chains and
reforms new chains that are needed in the body.
There are lots of different kinds of amino acids, and your body is able to make some of them
naturally. However, there are others that you have to get through eating certain high-protein foods.
These are called essential amino acids.
Protein-rich foods include; Beef, lamb, pork, chicken, fish, beans, nuts, peas etc.
Red
Meats
Beef
White
Meats
Chicken
Lamb
Pork
Turkey
Seafood
Oily Fish
White
Fish
Shellfish
Alternative Sources of Protein
Beans
Peas
Nuts
Tofu (From soya beans)
Quorn© (Mycoprotein, protein taken from fungus, and egg whites)
TVP (Textured Vegetable Protein, also from soya beans)
High Biological Value Proteins: Food source that contains all the essential amino acids for humans.
Normally animal sources like meat, poultry, fish, eggs and dairy products.
Low Biological Value Proteins: Food source that only contains some of the essential amino acids for
humans. Normally plant sources like legumes, grains, nuts, seeds and vegetables.
Eggs
Eggs are a good source of protein, vitamins and minerals
Functions of eggs in Cooking;
1.
2.
3.
4.
Binding- Eg. Burgers contains eggs to keep the meat together during grilling.
Coating – Egg washes are used to stick breadcrumbs to chicken pieces etc.
Glazing- Pastries can be glazed with egg to give a shiney appearance.
Emulsification- Eggs contain the protein lecithin, which helps to maintain emulsions, i.e. oil
and water mixtures and stop them from separating out.
5. Aeration – egg white traps air when beaten, as the protein expands.
6. Thickening- Egg whites coagulate at 60°C and yolks at 70°C, thickening the mixtures. E.g.
quiche.
6
Eggs and poultry are also a carrier of salmonella, a type of bacteria that causes food poisoning. To
prevent infection, poultry products must be cooked and stored properly, to kill the bacteria. Young
children, the elderly and pregnant women must pay particular care.
Fats and Oils
1.
2.
3.
4.
Butter
-Made by churning cream
Margarine
-Emulsions of vegetable oil
Lard
-Animal Fat, normally from pigs.
Suet
-Animal fat, specifically from area around kidneys and loins,
normally from cows or sheep.
5. Vegetable Oils
-Oils extracted from plants
6. Low-Fat Spreads
-Vegetable oils that have been hydrogenated, making them more
solid.
Uses of fats and oils in cooking





Greasing-Prevents food sticking to utensils and burning
Deep fat and shallow fat frying
Flavouring
Shortening-Solid fats are mixed with flour to make ‘short’ , crumbly pastry
Making emulsions with water based ingredients, e.g. mayonnaise.
Fats and Oils in the body





Source of energy for the body. Dietary fats and oils can also be stored in the body as fat for
use if energy is needed later.
Fat stores insulate the body, helping to maintain constant body temperature
Source of Fat-Soluble Vitamins e.g. Vitamins A, D, K, E.
Fats contain fatty acids, which play important roles in cell activities and are a vital
component of cell membranes in the body.
Fats contain cholesterol, which is also important in forming cell membranes and is essential
for producing hormones in the body.
o However, too much cholesterol can lead to heart disease
Saturated vs. Unsaturated Fats
Saturated Fats:
Usually found in animal sources.
7
Solid/Semi-Solid at room temperature
Contains high levels of cholesterol, increasing risk of heart disease
and heart attack.
Mono-Unsaturated Fats: Usually found in vegetable sources.
Liquid at room temperature, i.e. oils.
Generally a much healthier alternative to saturated fats.
Trans-Unsaturated Fats: Unsaturated fats, however, their structure is very similar to
saturated fats.
Generally not found naturally, produced artificially.
Can also have negative effects on health, e.g. heart disease.
Essential Fatty Acids:
Most fatty acids can be synthesised in the body, but there are some
that that only be got through dietary sources, called Essential Fatty
Acids.
Includes omega-3 and omega-6 fatty acids.
Found in foods including seeds, nuts and fish.
Essential in diet and important for cell activities.
Water
Water is the most essential part of the human diet. People can go weeks without food, but only a
few days without water.
Around 60% of the body is water.
It plays some role in almost every chemical reaction that occurs in the body.
People should drink about 2 litres of water a day.
Water can enter the body through drinks, but also in the food we eat, especially in fruit and
vegetables.
The body constantly loses water, nutrients and electrolytes through excretion, e.g. sweating,
urination and breathing etc. so it is essential that these are constantly replaced to prevent
dehydration.
8
Dehydration can lead to fatigue, dizziness, headaches, darker urine with less volume, drops in blood
pressure and fainting. If not treated immediately, dehydration can lead to kidney failure and death.
When treating dehydration, the body must also replace the lost nutrients and electrolytes.
Therefore, a lot of people rehydrate with sports drinks, which contain these molecules.
Vitamins
Fat Soluble Vitamins
Vitamin A:
Main dietary source is retinol, which can be obtained from liver, dairy products and
fish oils.
Another source is beta-carotene, from vegetables like carrots, pumpkin, and sweet
potato.
Vitamin A is important for good vision and eyesight.
Deficiency is vitamin A can lead to night blindness, dry eyes and possibly complete
blindness.
Vitamin D:
Can be found in oily fish and eggs in diet. However, vitamin D can be synthesised by
skin cells following exposure to sunlight.
Vitamin D is helps the body absorb minerals like calcium.
Vitamin D deficiency results in lack of absorption of calcium, resulting in dental
problems, weak bones and skeletal deformities like osteomalicia or rickets in
children.
Water-Soluble Vitamins
Vitamin B Complex:
Group of eight different vitamins; B1, B2, B3, B5, B6, B7, B9, B12.
Good sources of B vitamins include; whole grains, turkey, tuna, liver and
beans.
Thiamine (B1) has an important role in the breakdown of carbohydrates and
is also important for the central nervous system.
9
Riboflavin (B2) works with enzymes is many metabolic reactions in cells,
such as helping to generate energy from carbohydrates and fats.
Niacin (B3) also helps to generate energy from carbohydrates.
Folic Acid (B9) is important for the development of the baby during
pregnancy and helps to prevent spina bifida.
Vitamin C:
Found in citrus fruits, like oranges and lemons.
Vitamin C is important in healing scars, maintains healthy gums and connective
tissues and helps the immune system.
Vitamin C deficiency is called scurvy. It causes connective tissue in gums to
breakdown, and loss of teeth.
Minerals
Calcium:
Found in dairy products, nuts, broccoli and soya beans.
Essential for strong teeth and bones, also important in nerve signalling.
Deficency in calcium can lead to weak bones and problems like osteoporosis
later in life.
Iron:
Found in red meats, green leafy vegetables and nuts.
Important component in red blood cells.
Deficiency can result in anaemia.
Sodium (Salt (NaCl)):
Normally in the form of salt (NaCl) in foods.
Found in salt water fish and pork.
Important in regulating water levels in the blood, also plays an important
role in nerve signalling.
Too much salt can lead to high blood pressure and other heart problems.
Phosphorus:
Found in dairy products, meat, soya and fish.
Important in healthy bones and teeth.
Deficiency can cause muscle weakness and breakdown, as well as bone pain.
10
Flouride:
Chemical added to drinking water.
Promotes healthy teeth and prevents cavities.
Deficiency leads to increase in cavities.
Additives
Additives are substances added to food to improve its characteristics.
There are both natural and artificial additives.
Additives that are safe to use are given an E number.
1. Colourings: Added to change the colour of foods e.g. artificial additive tartazine which gives
foods a yellow colour, and natural caramel to give a brown colour.
2. Flavourings and Sweeteners: Added to improve the taste
o Natural herbs and spices like parsley and curry powder.
o Salt can be used to make food more savoury.
o Sugar and artificial sweeteners, like Splenda to sweeten foods.
o Monosodium Glutamate (MSG) is a flavouring that occurs naturally in the
productions of fish sauces, but can also be produced artificially as a food additive to
give a savoury flavour.
3. Emulsifiers: Used to maintain oil in water mixtures, e.g. lecithin in eggs used to stabilise
mayonnaise.
4. Gelling Agents: Causes substances to thicken, forming gels. Gelatine from animal bone, is a
natural gelling agent used to make jelly desserts, and seaweed extracts, like agar, can also be
used.
5. Raising agents: Commonly used in baking to add air to dough. Naturally occurring baker’s
yeast can be used to raise dough, as well as baking soda and sodium bicarbonate. Both
methods produce carbon dioxide when heated, the gas then expands allowing the dough to
rise.
6. Preservatives: Added to food to prevent spoilage. Salt is added to meat, sugar is added to
jams and vinegar can be used to pickle foods, all of which are natural preservatives.
7. Food fortification: Substances added to foods after processing to restore or give them
important dietary nutrients, e.g. iodine is added to table salt, and fluoride is sometimes
added to drinking water.
8. Anti-Caking Agents: Chemicals added to powdered food products to prevent clumping.
Acids and Alkali
Adding acids and alkali can have several functions in food;
o
Acids are used as preservatives to stop microbe growth, but can also be used as flavouring.
 Lemon juice and vinegar are used to flavour salad dressings, and also stops spoiling
of fruit and vegetables.
 Lemon juice also inhibits enzymes in fruit, preventing their natural decolouration
and decay.
 Vinegar is also used to pickle foods like eggs, and preserve them, and also to
marinate meats and tenderise them.
11

o
o
Vinegar is also added to meringue to partially degrade the proteins in the eggs,
improving the texture.
 Lactic acid from milk can go on to produce cheese and yogurt.
Alkalis, like bicarbonate soda can be used to raise dough. However, only small amounts are
used as alkalis have an unfavourable taste, and often flavouring is added.
Corn flour, an alkali, can be used to thicken mixtures like soups and sauces.
Disadvantages of Additives
1. Artificial food additives can be harmful. Some countries have banned certain food additives.
2. Some natural additives, like sugar and salt can also be harmful to health.
3. Some additives can cause allergic reactions.
Food and Energy
The body digests foods like foods to get energy. This energy can then be used in many different ways
in the body.
Mechanical-Energy is used by muscle cells to allow movement.
Chemical-Energy is used by the cells to carry out metabolic reactions.
Heat-Energy is used to maintain constant body temperature.
Electrical- Energy used to carry electrical messages through nerve cells.
The body’s energy requirement is measured in ‘Calories’.
People’s daily energy requirement varies depending on certain factors;




Gender- Men need 2500 calories a day, whereas women need only 2000.
Age- Babies need certain nutrients as they are growing and developing.
Level of physical activity- People who lead an active lifestyle and do a lot of physical
activities require much more calories to replace those lost in exercise etc., compared to
people who are inactive.
Pregnancy- When women are pregnant, their dietary requirements changes drastically, as
their body needs more energy, vitamins and nutrients as the baby develops.
o Pregnant women should also avoid fish high in mercury, undercooked meats and
sushi as well as unpasteurised milk products, like soft cheeses.
o They should also take 0.4mg of folic acid per day.
The body normally gets its energy from carbohydrates or fats.
Fats have twice the amount of calories than carbohydrates.
However, if the body is in starvation, i.e. the body hasn’t digested enough food and needs more
energy; cells can start to breakdown proteins to get energy.
12
Dietary guidelines -RDA
Women
Calories (Kcals)
Men
2000
2500
Total fat
70g
95g
Saturated fat
20g
30g
Unsaturated fats
50g
60g
Carbohydrates
300g
300g
45g
At least 5
portions
55g
At least 5
portions
7g max
(2.8g
sodium)
6–8
glasses
(1.2 litres
Protein
Fruit and Veg
Salt (sodium)
5g max (2g
sodium)
Water
6–8
glasses
(1.2 litres)
RDA-Recommended Daily Amounts.
This is the amount of each food you
should be eating, along with vitamins
and minerals for a healthy diet.
Eatwell Plate
Recommendations given by the UK government for a healthy diet, showing the proportions of the
different food groups.





Large portion of fruit and vegetables. Experts recommend 5 portions of fruit and vegetables
a day (80g in each).
Large portion of starcy foods, like bread, rice, potatos and pasta.
Medium amounts of protein from meats, eggs, beans, etc.
Medium amount of dairy products.
Small amounts of sugary/high fat food and drinks
13
Special Diets
Vegetarianism
Vegan: Diet with no animal-derived products e.g. meat, eggs, dairy, honey etc.
Lacto-ovo Vegetarian: Diet that allows dairy products and eggs, but not meats.
Lacto Vegetarian: Diet that allows dairy products, but not eggs, meat, etc.
Ovo Vegetarian: Diet that allows eggs, but not meats or dairy products, etc.
Health Problems and Diet
Diabetes: Diabetes (Type I and Type II) is a disease where sugar isn’t digested properly in the body,
resulting in high blood sugar levels. Treatment generally consists of drastically reducing the amount
of sugars in the diet, increase in exercise and possibly taking insulin injections
CHD (coronary heart disease): CHD occurs when blood vessels around the heart, called coronary
arteries, become blocked with plaques of cholesterol and fatty acids, potentially causing heart
attacks and even death. Treatments consists of placing stents in the vessels to open the blockages,
increasing exercise, and also eliminating foods rich in cholesterol, trans-unsaturated, saturated and
hydrogenated fatty acids.
Obesity: Obesity is caused by an increase in body fat levels normally caused by inactivity and poor
diet. High amount of fat can cause heart problems, diabetes and put pressure on other organs. Diets
low in fat and sugars is, and high in vegetables and lean meats is suggested in conjunction with
increases in exercise.
Nut Allergies: Allergies occur when the body recognises some foods, i.e. nuts, as harmful causing a
rapid immune response. People with nut allergies must eliminate all nut and nut-derived products
from their diet.
Celiac Disease: Autoimmune disease cause by body having a reaction with the protein gluten,
present in grains like wheat, barley and rye, resulting in digestive discomfort. Treatment involves
eliminating gluten foods from diet.
Gluten is commonly found in breads and other baked goods, as it is present in flour. Gluten gives
dough its elasticity and helps the bread to rise during baking.
Lactose Intolerance: Dietary disorder where the body is unable to properly digest lactose, a sugar
found in cow’s milk and its products. Also causes digestive discomfort, cramps, diahorrea and
vomiting. Treatment involves eliminating foods containing lactose from the diet.
14
Religious Beliefs and Diet Restrictions
Hinduism: People who follow Hinduism generally have a strict vegetarian diet. Some eat meat from
animals that have been slaughtered according to special laws, but almost all avoid beef.
Islam: People who follow Islam also have to adhere to dietary laws. All meat has to be Halal, i.e.
slaughtered according to special guidelines. Consumption of any pork is forbidden.
Judaism: People who follow Judaism must eat only kosher foods. Animals have to be slaughtered in
a special way for their meat to be kosher. Some meats, like pork, are banned. Followers also cannot
mix meat and milk in the same meal.
New Food Technologies
GM Foods: Genetically modified foods. These are foods that have had a gene from another organism
inserted into their cells to give them a favourable characteristic. Examples include golden rice, where
genes for vitamin A were inserted into a strain of white rice to combat vitamin A deficicency in
countries with rice as a main food source. Another example is pesticide resistant grain plants.
GM foods can grow quicker, thrive in poor environments, produce higher yields and have better
nutritional values. However, their long-term health effects are unknown, so some countries have
banned the sale of GM foods.
Food fortification: Foods that have had extra vitamins and minerals added to improve their
nutrional value., e.g. iodine is added to table salt, and fluoride is sometimes added to drinking water.
Biotechnology: This is the use of microorganisms to make products that are beneficial to humans.
An example of this is modifying E.coli to produce the enzyme chymosin to make cheeses, instead of
the traditional method of getting chymosin from animals stomachs.
Modified Starches: When starch is treated physically, biologically or chemically, etc. to give it new,
favourable properties. Examples include; Pre-gelatinized starch which can form gels without heating,
modified starch which can act as an emulsifying agent.
Food Contamination
Physical Contamination-When food is contaminated with objects, like unremoved packaging, hair
from worker etc., during cooking.
Chemical Contamination-When food is contaminated with chemicals during harvesting, storage, etc.
Biological Contamination-When food is contaminated with microorganisms.
15
Special precautions are taken to reduce the risk of contaminations in food, like having workers wear
protective clothing, storing food away from harmful chemicals and controlling storage and cooking
temperatures to inhibit microorganisms.
Food Poisoning
Food poisoning occurs when food contaminated with large numbers of harmful micro-organisms is
ingested.
Symptoms include fever, vomiting, stomach cramps and diarrhoea.
Bacteria, like Salmonella on poultry and eggs, are the main cause of food poisoning.
Bacteria thrive in moist, warm conditions (37°C) where food and nutrients are readily available.
Some foods are more prone to food poisoning than others;
Meats
Dairy Products
Poultry and Eggs
Fish and other Seafood
Cooked rice, pasta, etc..
Foods that are naturally dry or have been preserved have a much lower chance of causing food
poisoning.
To avoid food contamination;









Make sure all your food is in date and not damaged or already opened before cooking.
Store items correctly and use before they go out of date.
Wash your hands thoroughly before starting.
Wash all kitchen equipment and wear hygienic clothes, e.g. aprons, hairnets.
Use separate knives, chopping boards, etc. for raw meats and other produce, to avoid crosscontamination.
Don’t mixed cooked and raw food.
Always store raw products at the bottom of the fridge, so contaminants can’t drop onto
other foods.
Make sure meat is cooked all the way through.
Dump any leftovers or cover directly after use and store in the fridge/freezer.
Use by Date: Often displayed on perishable foods, like meats. Food must be consumed before this
date to avoid illness.
16
Best before Date: Often displayed on foods that can be stored for longer periods of time, such as
tinned or dried foods. This date is a measure of the quality of the food rather than the safety after
you eat it. Most foods are safe to be eaten after this date, except eggs, as they can carry salmonella.
Cooking temperatures
Food has to be cooked at temperature above 72°C to kill bacterial cells that cause food poisoning.
Food has to be stored at or below 4°C in the fridge to slow bacterial growth.
Food has to be stored at -18°C or lower in the freezer to stop bacterial growth.
Between 5-63°C is the danger zone for bacterial growth.
Temperature probes are used to measure the temperature inside of foods by sticking it directly in
the middle of the meats.
Food Preservation

Hot
o
o
o
o
o


Cold
o
o
o
Pasteurisation-Liquids heated to 72°C, then sealed and cooled to slow microbe
growth.
Sterilisation- Boiling liquid and then sealing container to kill all bacteria.
UHT (Ultra-Heat Treatment)-Heating liquids to high temperatures for a short
amount of time (1-2secs) to kill all microbes, then sealing in containers and cooled,
extending the shelf-life. Commonly used for milk.
Canning- Foods are heated to high temperatures, then sealed in metal tins and
allowed to cool.
Blanching-Fruit and vegetables are placed in boiling water, destroying ripening
enzymes, then taken out and frozen to keep their colour and prevent them going
brown.
Chilling-Placing food in the fridge at 4°C to slow microbe growth.
Freezing-Freezing the food by placing it in a freezer at -18°C to stop microbe growth.
Freeze drying- Cook-chill/freeze-Cooking the food, then placing in the fridge/freezer
to preserve.
Dry
o

Sun drying-Placing the food in direct sunlight, so moisture evaporates and microbes
are killed.
o Spray drying-Making a powder from a liquid by drying rapidly with hot gas.
o AFD (accelerated freeze drying)- Freezing the food, then drying it in vacuum. The
pressure in the vacuum turns the ice water into water vapour.
Chemical
o Preservatives
 Sugar-Sugar dehydrates the microbial cells when in high concentrations, like
in jams, etc., killing them
 Salt-Salt also dehydrates microbial cells, destroying them.
 Vinegar/Pickling-Acidic conditions inhibit microbe cell activities, killing them.
17
o
o
 Lemon Juice- Acidic conditions inhibit microbe cell activities, killing them.
Fermentation-Fermentation produces by products like acids and alcohols, which are
toxic to microbes.
Irradiation-UV light destroys microbial cells on the surface of foods.
Labelling
Informs the consumer about the properties of the food they are buying. Labelling must display the
following information:








Name of the food
o Description if needed
o Any special treatment or processing, for example, smoked, pasteurised.
List of all ingredients and additives
Instructions for use, cooking, storage
Date mark (use, sell by and best before)
Weight, volume etc. of product
Name and address of manufacturer
Place of origin
Any special details
o Ingredients that could cause allergies, e.g. nuts.
o Whether it was produced organically or genetically modified etc.
o Any other significant process or treatments during production.
Labels can also sometimes include;






Nutritional claim, e.g. low in fat, along with RDA details
Serving suggestion/Average portions
Opening instructions
Environmental issues, e.g. packaging disposal
Additional claims
o Free range, etc.
Information for retailer and manufacturer
o Bar codes
o Batch numbers
o Display until date
Food and Society
Food plays a large part in every society, and people often raise ethical issues about how their food is
produced. These include;
Factory Farming: Controversial method of farming where large numbers of livestock are kept in
small industrial factories to reduce costs. The animals are confined and unable to move around as
18
normal, often developing health and mental problems. The large numbers also means infectious
diseases can travel quickly through the farm.
Free-range: These are products that have come from animals (e.g. eggs from chickens) that have
been allowed to graze openly, compared to be enclosed like in factory farms.
GM Foods: Food that have been genetically modified to give them favourable properties. Long term
health or environmental effects of these foods are unknown.
Fair Trade: Much of our food originates in developing countries, where the labour is much cheaper.
Fair trade products insure that the people producing the food are paid a fair wage in their country.
Organic: Organic produce are foods that have been produced without the use of any chemicals, like
fertilisers or pesticides.
Farm Assured: Farm assured products can be traced back to the farm where they came from. It also
ensures that the farmer follows all the safety and hygiene guidelines, as well as animal welfare
guidelines set out by the local farming authority.
Generally, foods that are ethically produced are more expensive.
Environmental Issues
The production of food can also raise a number of environmental issues;
Producing food requires large amount of energy, and often uses up finite resources, i.e. resources
like fossil fuels that will run out eventually.
Factories can release excess greenhouse gases, like carbon dioxide, into the atmosphere,
contributing to global warming.
Farms can also release by-products (pollutants) into the local environment, causing adverse effects.
Some foods themselves are scarce, e.g. some species of fish. Therefore over harvesting of these
animals can cause adverse effects in the ecosystem.
Food Miles: The distance between the places of food production to place of sale. The more food
miles, the more energy required to transport the products, the worse the environmental effect.
Sustainability: Managing natural resources to ensure production has no harmful effects on the
environment, and the same resources can be continued to be used by future generations.
Pollution: The addition of harmful chemicals into the environment, causing harmful changes.
Waste Disposal: Food can be biodegraded in the environment. However, it is more difficult to break
down the packaging that comes with it. Packaging that can’t be reused or recycled is placed in
landfills.
The 6Rs
People can use the 6R’s to reduce their environmental impact.
19
Reduce: Reduce the amount of materials used in the product.
Reuse: Reuse some of the materials from other used products, or reuse your product again, e.g.
plastic water bottles.
Recycle: Breakdown the materials in the product, and reform them into something new, e.g. glass
crushed to sand and remade into more glass.
Repair: Repair broken machinery instead of buying new machines and dumping the old ones in
landfill.
Refuse: Don’t accept processes that aren’t the most beneficial for the environment.
Rethink: See if you can think of a better way to solve problems, while not harming the environment.
Packaging
Function of Packaging







Hygiene, i.e. protect the product from contamination
Increase shelf life
To show information in the labelling
Keep contents together
To allow for easier storage
To attract people to buy the product
Packaging must be safe and not react with the food
Packaging materials
Material
Plastic
Paper and
cardboard
Glass
Metal and
foil
Advantages
Lightweight
Can have different thicknesses, rigid or
flexible
Transparent
Some plastics can be reused
Disadvantages
Some plastics cannot be recycled
Takes a long time to biodegrade in the
environment
Lightweight
Biodegradable
Recyclable
Flexible
Cheap
Rigid
Transparent
Recyclable
Can be used in hot and cold temperatures
Can have different thicknesses, rigid or
flexible
Can be used in hot and cold temperatures
Some metals can be recycled
Not very strong or rigid
Not always waterproof
Fragile
Expensive
Heavy
Some metals cannot be recycled
Metals can react with foods. E.g.
20
Special Packaging
MAP (modified atmosphere packaging) -Commonly used with perishable foods (breads, meats, etc.)
-Food placed in packaging. The container is filled with
mixture of gases, like nitrogen and carbon dioxide, slow
down oxygen depended degradation and don’t allow
microbial growth, preventing spoilage. The packaging is then
sealed.
-This greatly extends shelf life until seal is broken.
Vacuum Packing
-Also used in packaging of perishable foods.
-Food is placed in packaging, and all the air is removed, creating a vacuum,
and then the packaging is sealed. The lack of oxygen prevents degradation
reactions and microbial growth, therefore increasing shelf life.
-However, once the seal is broken, the food can go off as normal.
Tamper-evident Seals
-These are seals added to food containers to indicate whether the packaging
has been opened or tampered with between production and purchase.
-Commonly seen on metal lids of sauce jars.
Environmental Effect of Packaging
Most of the food sold to people needs some sort of packaging.
It takes a lot of energy to make the packaging from raw materials, then more to prepare the finished
product and transport it to the market. This produces a lot of greenhouse gases and uses finite
resources.
A lot of this packaging used with food cannot be recycled, and is put in landfills.
In landfill, it can take hundreds of years for some materials, like plastics, to degrade.
Clearly, food packaging has a negative effect on the environment.
Because of this, many more companies are using sustainable packaging with recyclable and
biodegradable materials, to reduce their carbon footprint (i.e. their impact on the environment).
Cooking Terms
Aeration-Adding air bubbles to a dense mixture to make it lighter and fluffier.
Binding- Keeping all ingredients together in a mixture and preventing separation
21
Browning- The process of food becoming brown through chemical reactions. E.g. enzymatic
browning of fruit exposed to air, browning of meat to remove excess fats
Bulking- Substances that increase the mass of the food while cooking without affecting the taste, e.g.
starch.
Caramelisation- Browning sugar by heating it at high temperatures, making caramel.
Coagulation- Changing a liquid into a more solid masses, e.g. milk turning into curd.
Coating/Enrobing- Covering the surface of a food in a liquid or powder.
Colouring- Adding a substance to change the colour of a mixture.
Dextrinisation- When starch turns brown when heated, e.g. bread going to toast.
Elasticity- The ability a mixture has to stretch and stay intact.
Emulsification- Producing an emulsion, a mixture of oil in water.
Enriching- Can mean to add vitamins, minerals etc. to foods to improve its nutritional values. But, it
can also
mean adding cream or butter to a mixture to thicken it.
Fermentation- When yeast breakdown sugars to produce ethanol and carbon dioxide.
Finishing Techniques- Processes carried out to improve the appearance, taste, etc. of the finished
product.
Flavouring- Substance added to mixtures to improve the flavour.
Foaming- Aerating liquids to form lighter liquids with a lighter texture.
Fortification- The addition of vitamins, minerals, etc. into foods to improve their nutritional values.
Glazing- Coating foods in a solution to give a glossy finish, e.g. sugar-water mixtures give a sweet
tasting glaze.
Palatability- How well a food tastes.
Plasticity- How easy a mixture, e.g. bread dough, can be moulded into shapes.
Sealing- Frying meats quickly on a hot pan to retain the flavour.
Setting- The ability of a mixture to solidify into a permanent shape.
Shaping- The ability of a mixture to be moulded into shape.
Shortening- Mixing in solid fat into flour to give a crumbly pastry.
Tenderising- The breakdown of fibres in meats like beef, to make them less tough and more
palatable. Meat can be tenderised by mechanically breaking the fibres by pounding it with a mallet
or slow cooking the meat, or also by marinating in acids, like vinegar.
Thickening/Gelatinisation- The addition of a thickening/gelling agent into a liquid mixture to make it
less fluid. If allowed to cool fully, the mixture can become a gel.
22
Production Methods
One-Off Production
o
o
o
o
Produces a single, unique product.
Doesn’t use much machinery.
Requires skilled workers to make product.
Generally high quality, but also high cost to make and time consuming.
Batch Production
o
o
o
o
o
o
o
Large amounts of the same product are made at once.
Work is done by both workers and machines.
Doesn’t require skilled workers.
Much quicker than one-off production.
Cheaper than one-off production as some of the processes are automated.
Machines have to be cleaned and sterilized after each batch.
Whole batch has to be changed to change one product.
Mass Production
o
o
o
o
Making large amounts of standard products.
Often done on production lines, so products are made quickly.
Mix of workers and machines.
Whole production line has to be changed to change product.
Continuous Flow
o
o
o
o
o
o
o
24/7 production line.
A single product is made continuously, without regularly changing the batch.
Work is done by mostly machines, low labour costs and no human error.
As products are constantly made, very cheap.
Machines are expensive.
If any problems arise, all production must stop to fix the problem.
Only one product can be made at once.
CAD, CAM and ICT
CAD (Computer Aided Design)
o
o
o
o
o
This is where computer programs are used to design the product.
Models can be seen on the computer, and then dimensions can be changed to match the
design.
Packaging designs can also be made on modified easily with CAD.
Much more accurate and cheaper than drawing by hand.
Requires a skills worker to use the program correctly.
CAM (Computer Aided Manufacturing)
o
o
o
This is where computers are part of the manufacturing process, controlling the machines
that manufacture the product.
CAM is more accurate and efficient than traditional production methods.
Lower production costs as less staff needed.
23
o
o
Products made are identical
Safer and more hygienic.
ICT (Information and Communication Technology)
o
o
Computers are used in some form in almost every company.
Programs can be used to monitor amounts of ingredients, take stock of products, manage
accounts etc.
24