chapter 13 - reactions in food during preparation and cooking

Question 1

what are the reactions in carbohydrate

Answer 1

gelatinisation
dextrinisation
caramelisation

Question 2

what are the reactions in protein

Answer 2

maillard browning
denaturation 
foaming
coagulation 
gluten development

Question 3

what are the reactions in fats

Answer 3

shortening

emulsion

Question 4

what are the reactions in fruit

Answer 4

enzymatic browning

Question 5

explain gelatinisation

Answer 5

when starch granules (amylose and amylopectin) are heated in the presence of water
it absorbs the water and swells
upon further heating, thick consistency is obtained
resulting in soft texture fr e.g. rice becomes fluffy after steaming

Question 6

explain dextrinisation

Answer 6

when starch is exposed to dry heat at high temperatures
long-chain starch molecules break down into dextrins
result in a toasty and nutty flavour

Question 7

explain caramelisation

Answer 7

where simple sugar turns brown when heated to a high temp
during this process, the sugar turns from thick, light brown syrup to a soft dark brown mass
it contributes to a caramel flavour (sweet, bitter and nutty)

Question 8

explain maillard browning

Answer 8

is the reaction between sugars (glucose and fructose) and proteins at a high temp. forms = maillard browning
result in desirable brown colour and aromatic smell

Question 9

explain denaturation

Answer 9

when proteins are subjected to
heat agitation or extreme pH changes
causes protein strands to uncoil (changes the physical appearance and texture of food) and lose their original structure

Question 10

explain foaming

Answer 10

when air is trapped in liquid or solid

when an egg is beaten, protein strands denature + wrap and the air bubbles = volume increases

Question 11

explain coagulation

Answer 11

is the solidifying or curdling of protein rich food
occurs when heat or acid is applied onto protein-rich food
protein strands uncoil, further heating results in a network being formed
this changes protein from liquid to semi-solid or solid-state

Question 12

explain gluten development

Answer 12

when wheat flour - wheat proteins (gliadin and glutenin) and water are subsequently kneaded,
it rearranges the gluten to form a network of dough upon further mixing

Question 13

explain shortening

Answer 13

when water is added to wheat flour,
it reduces contact between water and flour
= fewer gluten networks are formed

Question 14

explain emulsion

Answer 14

by combining 2 liquids that mix

an emulsifier needed to stabilise fr e.g. water and oil mixture

Question 15

explain enzymatic browning

Answer 15

when the flesh of the fruit is exposed to oxygen in the air
the brown discolouration is formed
vitamins are also destroyed through oxidation

Question 16

explain how to prevent enzymatic browning

Answer 16

cut fruit and vegetable just before use or consumption

keep fruit in a chiller, in cling wrap

Question 17

what is the function of raising agents

Answer 17

are used to increase the volume of cakes

Question 18

name the chemical raising agent

Answer 18

baking powder or soda

Question 19

name the physical raising agent

Answer 19

air and steam (from water)

Question 20

why do we need to sift flour

Answer 20

to remove lumps from flour incorporate air

Question 21

what are the common methods of cake making

Answer 21

rubbing in
creaming
whisking

Question 22

what is the method of pastry making

Answer 22

shortcrust making

Question 23

what are the methods of batter making

Answer 23

thin batter

thick batter

Question 24

what are the methods of sauce making

Answer 24

roux sauce

blended sauce

Question 25

what are the 6 common ingredients used in baking and food preparation

Answer 25

``` flour liquid (water/ mil etc) fat egg raising agent sugar ```

Question 26

what is the function of flour in pastry making

Answer 26

form structure via gluten formation

Question 27

what is the function of flour in batter making

Answer 27

form structure via gelatinisation

Question 28

what is the function of flour in cake making

Answer 28

browning due to dextrinisation

Question 29

what is the function of liquid in pastry making

Answer 29

physical raising agent (steam)

Question 30

what is the function of liquid in batter making

Answer 30

binding agent for dry ingrediants

Question 31

what is the function of liquid in cake making

Answer 31

solvent for dissolving soluble ingredients

Question 32

what are the function of fat

Answer 32

contributes colour and flavour provides tender texture traps air during creaming

Question 33

what are the functions of egg

Answer 33

emulsifier binding agent - cake, biscuits & batter foaming - sponge cake

Question 34

what are the functions of sugar

Answer 34

``` it browns due to caramelisation and maillard browning maintains moistness provides sweetness provide tender texture trapping air during creaming and foaming ```

Question 35

why do we sift four

Answer 35

to remove lumps from the flour | to incorporate air

Question 36

in the rubbing in method, why do we cut cold fat into small pieces

Answer 36

to make rubbing in process faster and easier

Question 37

In the rubbing in method, why do we rub fat into the mixture

Answer 37

to prevent fat from melting as the fingertip is the coolest part of the finger

Question 38

in creaming method, why do mix the mixture using an electric whisk

Answer 38

to trap air bubbles in the mixture

Question 39

in creaming and whisking method, why do we gently fold the sifted flour into the mixture with a spatula

Answer 39

to prevent knocking out the air bubbles | to allow even distribution of the ingredients

Question 40

what will happen to the cake if you set the temperatures too high

Answer 40

the cake will crack

Question 41

what is the cause of a sunken cake

Answer 41

adding too much baking powder or liquid

Question 42

what is the cause of a cake with uneven air cells

Answer 42

incorporating too much air into the cake mixture

Question 43

what are the cause of a dense and close texture cake

Answer 43

adding too much flour to the cake mixture setting the oven temp too low incorporating insufficient air into the cake mixture

Question 44

what happens if you add too much liquid to the biscuit mixture

Answer 44

it will become a wet and sticky dough | undesirable spreading of biscuits

Question 45

what happens if you bake the biscuits for too long

Answer 45

result in a hard and dry biscuits

Question 46

what happens if you add too much flour to the biscuit mixture

Answer 46

result in a hard and dry biscuits

Question 47

what happens if the butter melt in the biscuits dough before baking

Answer 47

undesirable spreading of biscuits

Question 48

in shortcrust pastry, why do we wrap the dough in cling wrap and let it rest in the refrigerator

Answer 48

to prevent loss of moisture

Question 49

why do you lightly floured the surface before rolling out the dough

Answer 49

to prevent the dough from sticking to the surface

Question 50

in shortcrust pastry, why do we prick the base of the dough in the baking tin using a fork

Answer 50

to allow steam to escape so as to prevent uneven surface

Question 51

what happens if you forgot to prick the dough before baking in shortcrust pastry

Answer 51

results in an unevenly risen pastry

Question 52

what happens if you do not allow the dough to rest sufficiently in shortcrust pastry

Answer 52

result in an unevenly risen pastry a shrunken pastry a tough and hard pastry

Question 53

what happens if you over handle the dough in shortcrust pastry

Answer 53

result in a shrunken pastry a tough and hard pastry

Question 54

what happens if you use too much flour when rolling out the dough

Answer 54

result in a tough and hard pastry

Question 55

what happens if you add too much liquid into the mixture

Answer 55

result in a tough and hard pastry

Question 56

in thin batter making, wy do we whisk the mixture while pouring in the remaining liquid

Answer 56

to allow the incorporation of air | to create a smooth and to prevent lump formation

Question 57

what causes a runny coating batter

Answer 57

adding to much liquid into the batter

Question 58

why does the fried battered food have a soggy texture

Answer 58

did not drain the oil from the food after cooking | not ensuring the oil is hot enough during frying

Question 59

what causes a raw food within the cooked batter

Answer 59

not frying long enough | using oil at a high temp during frying

Question 60

what causes a lumpy batter

Answer 60

not whisking the batter long enough | adding hot liquid into the flour

Question 61

why do we add sauce to a dish

Answer 61

impart flavour to the dish add colours to the dish contributes to the variety of textures in some dishes complement the richness of meat dishes