Carbohydrates Flashcards
Elements
Carbon
Hydrogen
Oxygen
Classification
Monosaccharide
- Simple unit of sugar containing one single sugar unit
Disaccharide
- formed when two monosaccharides join resulting in loss of water molecule
Polysaccharide
- formed when three or more monosaccharides join resulting in loss of water molecule at each new link
Monosaccharide Chemical formula
C6 h12 o6
Examples of monosaccharides
Glucose- Fruit
fructose- fruit and honey
Galactose- Digested milk
Draw the chemical structure of a monosaccharide
Check book page 18
Disaccharide chemical formula
C12 h12 o11
Examples of disaccharides
Maltose = glucose + glucose barely Sucrose = glucose + fructose table sugar Lactose = glucose + galactose milk
Polysaccharide chemical formula
(C6 h10 05)n
Examples of polysaccharides
Starch = cereals and potatoes pectin = fruit and nuts glycogen = meat gums = plants and seaweed cellulose = skins of fruit and vegetables
Properties of sugar
Chasmics Crystallisation Hydrolysis Assists aeration Solubility Mailard reaction Inversion Caramelisation Sweetness
Solubility
soluble in water
Eg sugar in hot tea
Sweetness
Sweet
-Fructose in ripe strawberry is sweeter than lactose milk
Assists aeration
Helps denture protein in egg white allowing it to trap air and form a phone
Mailard reaction
Amino acid + sugar + dry heat = browning example toast
caramelisation
When sugar is heated on its own (dry heat) it melts and forms Carmel 177°C and eventually burns carbonises
Properties of starch
Solubility Flavour Gelatinisation Hydrolysis Dextrinisation Hygroscopic
Flavour of starch
Not sweet
Solubility of starch
Insoluble in cold water
Gelatinisation
Starch grains (in flour) are heated (78°C) in liquid they swell and burst thickening liquid Example soup or roux sauce
Hygroscopic
Starch has ability to absorb moisture from air
- busicuits go soft if not stored in sealed container
Dextrinisation
Dry heat is applied to starch short chained polysaccharides (dextrins) are changed to pyrodextrins causing browning eg toast
Hydrolysis
During Digestion when water and enzymes split starch (polysaccharides) into maltose (disaccharides)
Effect of dry heat
- mailard reaction (sugar) eg roast beef
- caramelisation (sugar) eg creme Carmel
- dextrinisation (starch) eg toast
Effects of moist heat
- syrup formation (sugar) eg syrup in canned peaches
- gelatinisation (starch) eg white sauce
Digestion
Mouth
=saliva - salivary amylase - starch - maltose
Pancreas
=pancreatic juice - amylase - starch - maltose
Small intestine
= intestinal juice - maltase - maltose - glucose
- sucrase - sucrose - glucose + fructose
- lactase - lactose - glucose + galactose
