carbohydrates

Question 1

what is photosynthesis

Answer 1

the process by which green plants use energy from the sun to change carbon dioxide and water into glucose and oxygen

Question 2

what are the three types of carbohydrates

Answer 2

monosaccharides, disaccharides and polysaccharides

Question 3

what is a monosaccharide

Answer 3

one sugar unit, C6H12O6, examples are fructose, glucose and galactose

Question 4

what are disaccharides

Answer 4

they are formed when two monosaccharides join together with the elimination of water, examples are maltose, sucrose and lactose. the chemical formula is C12H22O11

Question 5

What is a polysaccharide

Answer 5

formed when two or more monosaccharides join together with a loss of a water molecule each time, they may be straight or branched. examples are starch, pectin, gums and glycogen, their chemical formula is n(C6H10O5)

Question 6

What are NSPs?

Answer 6

nonstarch polysaccharides that cannot be digested and absorb large amounts of water

Question 7

what is peristalysis

Answer 7

the muscular movement of food along the gut

Question 8

what are sources of NSPs

Answer 8

wholemeal bread, brown rice and wholemeal pasta

Question 9

what are the properties of sugar

Answer 9

solubility, flavour/sweetness, assists aeration, caramelisation, crystalisation, hydrolysis, inversion, Maillard

Question 10

what is solubility of sugar + culinary app

Answer 10

sugar is soluble in water, a syrup is formed when a large amount if sugar is dissolved in a small amount of water, culinary ap is canned peaches to preserve

Question 11

what is the flavour of sugar + culinary app

Answer 11

sugar is sweet and gives an appetising flavour to food, sweetness is measured on a percentage scale for example fructose is 170%, culinary app: shortbread

Question 12

what is asissts aeration of sugar + culinary app

Answer 12

occurs when sugars are whisked with egg whites, sugar helps to denature the egg protein, culinary app: meringues

Question 13

what is the maillard reaction of sugar + culinary app

Answer 13

non enzymic browning of food due to a reaction between amino acids and sugars under dry heat results in an attractive brown colour and a crust with appetising flavour. culinary app: shortbread

Question 14

what is caramelisation of sugar + culinary app

Answer 14

when sugar is heated it melts and caramelises which occurs over 10 gradual stages, caramelisation occurs at 160 degrees culinary app: creme caramel

Question 15

what is crystallisation of sugar + culinary app

Answer 15

when a liquid has dissolved as much sugar as it can it is saturated, if more sugar is added crystals of sugar form and solidify when cooled. culinary app: fudge

Question 16

what is hydrolysis of sugar

Answer 16

hydrolysis is the addition of a water molecule. disaccharides react with water and enzymes which breaks down sugar to two monosaccharide units

Question 17

what are the properties of starch

Answer 17

flavour, solubility, hygroscopic, dextrinisation, gelatinisation and hydrolysis

Question 17

what is inversion of sugar + culinary app:

Answer 17

inversion occurs when a liquid sucrose solution is heated in the presence of an acid or enzyme to split it into glucose and fructose, this is sweeter than sucrose, culinary app: jam making

Question 18

what is the flavour of starch

Answer 18

not sweet

Question 19

is starch soluble in water

Answer 19

it is insoluble in cold water

Question 20

what is hygroscopic in starch

Answer 20

how starch absorb moisture from the air eg how biscuits soften if not kept air tight

Question 21

what is dextrinisation + culinary app

Answer 21

dextrins are shorter chains of starch, on heaing, dextrins form longer chains and become brown coloured substances call pyrodextrins a culinary app is toasting bread

Question 22

what is gelatinisation of starch + culinary app

Answer 22

as temperature rises, the mixture becomes even more viscous, forming a sol, on cooling this becomes a gel a culinary app is using flour to thicken soups and sauces

Question 23

what is hydrolysis of starch

Answer 23

a chemical breakdown of a molecule by adding water to produce smaller molecules

Question 24

what is dietary fibre

Answer 24

it is insoluble in water and cannot be digested by the body but gives bulk to the diet as it absorbs water as it passes through the intestinal tract and stimulates the removal of waste from the body by peristalsis, this speeds up the passage of food preventing bowel disorders

Question 25

how would you increase fibre intake

Answer 25

reduce sugar intake and refined starch and include whole grains in the diet. choose brown bread, pasta and rice, add bran seeds and nuts and increase fruit and veg intake

Question 26

what are gums + culinary app

Answer 26

they are soluble in water and have the ability to absorb large amounts of water to form a thick gel with a firm texture, culinary app: ice cream

Question 27

what are the properties of pectin + culinary app:

Answer 27

naturally present in plant cells and cell walls of fruit and veg, used as a setting agent in jams and jellies as it has the ability to absorb water to form a gel. it is only present in fruits when they are ripe, pectin can only be extracted with heat and acid, culinary app: jam making

Question 28

what are the effects of dry heat on carbohydrates

Answer 28

dextrinisation, caramelisation and maillard reaction

Question 29

what are the effects of moist heat on carbohydrates

Answer 29

cellulose softens eg cooked vegetables, gelatinisation, inversion, solubility

Question 30

biological functions of carbohydrates

Answer 30

used for heat and energy in the body, spare protein so it can be used for growth and repair, excess carbohydrates are converted to glycogen and stored in the liver and muscle as an energy reserve or stored as adipose tissue to insulate, cellulose/fibre moves food through intestine preventing constipation

Question 31

describe the digestion of carbohydrates

Answer 31

salivary amylase breaks starch into maltose in the mouth, they are physically churned in the stomach, in the intestine, amylase in pancreatic juice breaks starch into maltose. in the intestinal juice: maltase breaks maltose into glucose, sucrase breaks sucrose into glucose and fructose , lactase breaks lactose into glucose and galactose.

Question 33

how are carbohydrates absorbed in the body

Answer 33

monosaccharides are absorbed through the villi of the small intestine into the blood stream and are carried to the liver in the portal vein