Download Student Module_1-2_Carbohydrates

The
Carbohydrates:
Sugar, Starch
and Fiber
Module 1.2
Carbohydrate (Carbs or CHO)
• Carbohydrate-obtained almost exclusively
from plants (fruits, vegetables, grains)
– Milk is the only animal-derived food with
significant carbohydrate.
• Organic Compound: made of the elements
carbon, hydrogen, and oxygen.
– classified organic due to carbon content
– compound - has more than one element in
its structure.
• Produced by photosynthesis: converts light
energy into chemical energy
– C6H1206 + 6O2 = 6C02 + 6H2O + energy
• Chloroplasts composed of proteins with green chlorophyll pigment which
absorbs sun’s energy
• Provides 4 Calories/gram.
• The preferred fuel for the body; especially brain and nervous system.
• It is high performance fuel; produces ATP at the fastest rate.
• Should consume 45-65% of caloric intake from carbohydrate
• Dietary recommendation for fiber 1.4 gram per 100 caloric intake
Carbohydrate Basics
 Simple Carbohydrates
Sugars
1. Monosaccharides –single sugar unit
2. Disaccharides – two sugar units
 Complex Carbohydrate
Oligosaccharides and polysaccarides
Types
1. Starch
2. Glycogen –storage form of glucose
3. Fiber - indigestible
Categories of Carbohydrate
Simple- sugars
Complex : two forms
• Monosaccarides
– Glucose
• blood sugar
– Fructose
• fruit sugar, honey
– Galactose
• milk sugars
Polysaccharides: Starch
• ALPHA linked glucose molecules in
starch are broken apart by enzyme
alpha-amylase to produce energy.
– The glucose units that are
released are absorbed into the
blood stream.
Fiber: indigestible
• BETA linked glucose molecules
cannot be broken apart by human
enzymes; no energy is produced.
– The glucose units not released;
thus fiber is not absorbed.
– Cellulose is the most common
type of fiber
• Disaccarides
– Sucrose - table sugar
• glucose + fructose
– Lactose - milk sugar
• galactose + glucose
– Maltose - grain sugar
• glucose + glucose
Monosaccharides
α-D-Glucose
β-D-Fructose
β-D-Galactose
Disaccharides
α-Sucrose
Glucose + fructose
α-Maltose
Glucose + glucose
β -Lactose
Glucose + galactose
Complex Carbohydrate
Starch : plant polysaccharide composed of hundreds of
repeating units of glucose, digestible by human beings
Forms
 Amylose Unbranched chains
of glucose Constitutes
about 20% of starch
 Amylopectin –
branched chains of
glucose used as a
thickener; enzymes
digest more rapidly.
Constitutes 80% of
starch
 Starch is a composite
of both types
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Polysaccharides
Carbohydrate Food Sources
• Grains, Cereals, & Legumes: Pasta, bread, cold/hot cereal,
rice, oats, kidney beans, etc.
• Fruits & Vegetables
– Starchy Vegetables: Corn, potato, peas, acorn squash, etc.
Plant Carbohydrate Sources
– Simple carbohydrates: Fruit, table sugar, sweets & sugar
sweetened cereals.
– Complex carbohydrates: Vegetables, starchy vegetables,
grains, legumes, & whole grain cereals.
– Milk (& milk products yogurt & cheese) contain lactose.
– Honey contains glucose, fructose & small amounts of other
sugars.
Animal Carbohydrate Food Sources
– Animal foods usually provide mostly protein & fat.
– Milk & milk products also provide protein & varying amounts
of fat
CHO Enzymatic Action
• An enzyme is a protein that acts as a catalyst in a
biological reaction.
• Enzyme Amylase digest CHO such as sugars / starch.
• CHO digestion begins in the mouth stops in the stomach
(pH 2.0) where amylase is inactivated or destroyed in when
pH falls below 6.5.
• Digestion completed in the small intestine with the help of
the intestinal enzymes (maltase, lactase) Pancreatic
amylase joins maltase and lactase to continue the
digestion of carbohydrates in the small intestine where pH
increases to 6.5.
• Amylase breaks down starches into a disaccharide. Most
starch is broken down to the disaccharide maltose then
into single sugars, such as glucose.
Carbohydrate Digestion
Plant
Carbohydrate
Sources
http://www.time-to-run.com/nutrition/wp-content/uploads/carbo.590.jpg
Animal
Carbohydrate
Food Sources
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Alcohol: CH3CH2O
• A clear, colorless volatile liquid (boils @ 172 degrees much lower
than water.)
• Shares similar properties as water therefore travels through the
body like water. Easily moves across cell walls into tissues/cells
• Alcohol is a small molecule that requires no digestive process
to be absorbed.
• Acts as a sedative and central nervous system depressant.
• Fats and lipophylic substances easily dissolve
in alcohol. Used to extract flavors and
transport medications
• A non-nutrient that is not stored in the body.
• Alcohol forms the glycerol backbone in
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fatty acids.
8/MDA2008/MDA2009/alcoholicbeverages
2.jpg
• Supplies energy (7 calories/ 1 gram).
• One serving per day may reduce heart disease risk but increases
cancer risk.
Alcohol Absorption / Metabolism
 Alcohol is a small molecule that requires no digestive process to
be absorbed.
• About 20% of alcohol is absorbed in the stomach and
about 80% is absorbed in the small intestine.
• Body expels 10% of alcohol through perspiration,
lungs, and urine
• 90% to be metabolized by the liver.
 A average healthy person’s liver can eliminate .25 oz 0.5 oz. of alcohol PER HOUR.
 This leaves the remaining alcohol to continue circulation
throughout the body until it is consumed affecting the brain
and every tissues, organ and cell.
Process:
1.Alcohol + alcohol dehydrogenase → acetaldehyde (carcinogen)
2.acetaldehyde → acetate
3.acetate → carbon dioxide (CO2) and water
Absorption/Metabolism Influences
Rate of alcohol metabolism affected by:
• AMOUNT of alcohol dehydrogenase available
• FOOD - Fat delays stomach emptying so the alcohol reaches the
intestines slower. Alcohol on an empty stomach can reach the
absorption within 5 minutes.
• GENDER Male/female drink ratio = 2:1
 female less water; smaller body size; smaller livers
 Women absorb 30% more alcohol
 Enzymes – alcohol dehydrogenase is 40% less active in
women’s stomachs
• Blood alcohol concentrations - % of alcohol in the blood.
• Legal limit = 0.08% (0.08% or one tenth of one percent - 1%)
means that there are 0.08 g of alcohol for every dL of blood.
• BAC 0.35% = unconsciousness threshold
• BAC 0.40% = coma
• BAC 0.45% = death