Carbohydrates

Question 1

Word equation for photosynthesis

Answer 1

Carbon dioxide + water –> glucose + oxygen

Question 2

Chemical equation for photosynthesis

Answer 2

6Co2+6H2O–>C6H12O6+6O2

Question 3

Structure of a monosaccharide

Answer 3

Simple sugar, one unit, smallest carbohydrate

Question 4

Monosaccharide chemical formula

Answer 4

C6 H12 O6

Question 5

Example and sources of monosaccharides

Answer 5

Glucose - fruit
Fructose- fruit and honey
Galactose - digested milk

Question 6

Disaccharide structure

Answer 6

When two monosaccharides join together

Loss of H2O

Question 7

Chemical formula of a disaccharide

Answer 7

C12 H22 O11

Question 8

Examples and sources of disaccharides

Answer 8

Maltose(glucose + glucose) = barley
Sucrose ( glucose + fructose) = table sugar
Lactose (glucose + galactose) = milk

Question 9

Structure of a polysaccharide

Answer 9

2+ monosaccharides join together

Question 10

Chemical formula of polysaccharide

Answer 10

(C6 H10 O5)n

Question 11

Examples and sources of polysaccharide

Answer 11

Starch -potatoes 
Pectin -fruit 
Glycogen -meat 
Gums -plants and seaweed 
Cellulose dietary fibre -nuts

Question 12

Properties of sugar

Answer 12

Soluble in water 
Sweetness 
Assists aeration 
Maillard reaction 
Caramelisation 
Crystallisation 
Hydrolysis 
Inversion

Question 13

Explain solubility of sugar

Answer 13

A syrup is formed when it is dissolved in water

Culinary use : preservative in food e.g. Canned peach

Question 14

Explain sweetness of sugar

Answer 14

Gives appetising flavour

Culinary use : cupcakes

Question 15

Name the types of sugar

Answer 15

Fructose
Glucose
Sucrose
Lactose

Question 16

What is the sweetness in fructose

Answer 16

170%

Question 17

What is the sweetness in sucrose

Answer 17

100%

Question 18

What is the sweetness in glucose

Answer 18

75%

Question 19

What is the sweetness in lactose

Answer 19

15%

Question 20

Explains assist of sugar in aeration

Answer 20

Sugar helps denature eggs protein causing it to unfold and entrap air bubbles

Culinary use: meringues

Question 21

Explain caramelisation of sugar

Answer 21

On heating sugar melts and caramelises.
Gradual stages between 104-177 degrees
Normally occurs at 160 degrees

Culinary use : caramel squares.

Question 22

Explains crystallisation of sugar

Answer 22

When a liquid has dissolved as much sugar and possible it is saturated. Crystals are formed when the solution solidifies when cools

Culinary use : fudge

Question 23

Explain hydrolysis of sugar

Answer 23

Reverse of condensation reaction.

Water and enzymes splits disaccharides back into monosaccharides

Question 24

Explain inversion of sugar.

Answer 24

When a liquid sucrose solution is heated in the presence of an acid or enzyme is causes the disaccharide to split into glucose and fructose

Culinary use: jam making

Question 25

Properties of starch

Answer 25

``` Solubility Flavour Hygroscopy Gelatinisation Hydrolysis Dextrinisation ```

Question 26

Explain hydrolysis of starch

Answer 26

Occurs during digestion | Water and enzymes split starch(poly) into maltose (dis)

Question 27

Explain dextrinisation of starch

Answer 27

When starch foods are dry heated short chained polysaccharides called dextrins are formed They combine to form pyrodextrins This causes colour change. Culinary use : browning of toast

Question 28

Explain solubility of starch

Answer 28

Insoluble in water

Question 29

Explain starch flavour

Answer 29

Non sweet

Question 30

Explain hygroscopy of starch

Answer 30

Can absorb moisture from air

Question 31

Explain gelatinisation of starch

Answer 31

Hen starch is co,boned with liquid and heated to 55-70 degrees grains swell burst and absorb liquid around them. As temperature increases it becomes more viscous and forms a sol When mixture cools water molecules become trapped resulting in a gel

Question 32

Properties of non starch polysaccharides

Answer 32

Gums Cullulose Pectin

Question 33

Explain the property cellulose

Answer 33

Cellulose / dietary fibre is insoluble in water. Cannot be digested by body passes through intestinal tract and helps stimulate peristalsis

Question 34

Explain gums

Answer 34

Soluble in water Can absorb large amounts of water to form a thick gel Culinary application: ice cream.

Question 35

Explain pectin

Answer 35

``` Naturally present in plant cells and cell walls of fruit and veg Used as a Setting agent Absorbs water to form a gel Only present in ripe fruit Over ripe fruit = pectic acid Under ripe fruit = protopectin For pectin extraction it needs heat and acid Culinary application: jam making ```

Question 36

Effects of dry beta on carbs

Answer 36

Dextrinisation Caramelisation Maillard reaction

Question 37

Effects of moist heat on carb

Answer 37

Syrup form Gelatinisation Cellulose Pectin extraction