Food Components

Question 1

Water Activity (aw) - A measure of the amount of _______ ____ in foods to: ___________ or _________
and ranges from __ to __
aw<0.85 -> __
adding solute to water _______

Answer 1

available water

be used by microorganisms causing spoilage or
migrate within a food and degrade quality

0 to 1.00

inhibits food spoilage

lowers water activity because water molecules are orientated around the solute and less available for microbial growth

Question 2

Composition of water
2H+O = H2O

Each water molecule is electrically ________ - ____
Positively charged end ___
Negatively charged end ___
Hydrogen bonds

Answer 2

unsymmetrical - polar

hydrogen

oxygen

Question 3

1 kilocalorie = ______

Specific heat = ______

The specific heat of water = _____

Because of hydrogen bonding, it takes _____ more energy to heat than any other substance

Answer 3

the amount of water required to raise 1 kilogram of water 1 degree

the amount of heat required to raise the temperature of 1 gram of a substance 1 degree

1.00

water

Question 4

Freezing point of water:

Heat of solidification:

In water this occurs ______

Answer 4

32 degrees f/ 0 degrees C

The temp at which a liquid converts to a solid

When > or = to 80 calories of heat are lost per gram of water

Question 5

Melting point of water: ____________

Returning ___ calories of heat to a gram of ice will cause it to reach its melting point

Answer 5

The temp at which a solid turns to a liquid

80

Question 6

Boiling point of water - heated liquid begins to boil and changes to a gas at ____

Heat of vaporisation: ____

___ calories of energy are needed to boil and vaporise __ of water

The boiling point of water decreases with _____
The boiling point of water increases when we increase the _________

Answer 6

212 degrees f/100 degrees C

The amount of heat required to convert liquid to a gas

540
1g

Elevation
Atmospheric pressure

Question 7

Solution: completely homogenous mixture of a _____ dissolved in a ______

Colloid solution: dispersion in which the particles are ____ nm to ___ microm in diameter and therefore too ____ to go into a solution but not ____ enough to precipitate out of the continuous phase

Suspension: dispersion in which the particles are _______ than the ___ microm diameter and remain suspended in the continuous phase

Answer 7

solute
solvent

2
1
large
large

larger
1

Question 8

Acid-base reactions (availability of __ and __)

Salt formation (__ + __ -> ___)

Hydrolysis (_____ -> _____)

Condensation (_____ -> _______)

CO2 release (____+ ___ & ____)

Answer 8

H+ & OH-

Na+ + Cl- -> NaCl

corn starch -> corn syrup

monosaccharides -> disaccharides

baking soda + acid & water

Question 9

Carbohydrate functions

Answer 9

Sweetness
Colour/Browning
Texture/Volume
Alcohol source
Preservation

Question 10

Relative sweetness of monosaccharides and disaccharides

Glucose -
Fructose -
Galactose -
Maltose -
Sucrose -
Lactose -

Answer 10

50
150-180
26
40
100
20-40

Question 11

Functions of Proteins in foods

Answer 11

Hydration
Browning
Denaturation/Coagulation
Enzymatic reactions
Buffering
Thickening

Question 12

Functions of Lipids in foods

Answer 12

Heat Transfer
Tenderness
Emulsification
Texture
Flavour

Question 13

Vitamins:
- _____ molecules
- ______ complex molecules
- provide ____ to food
- cooking process impact ______
- Vitamin _ used as an additive

Answer 13

organic
large
colour
retention
C

Question 14

Minerals:
- ________
- ____ ____ has multiple roles in food preparation:
____, ______ & ______
- iron, calcium and sulphur also have specific food chemistry implications

Answer 14

inorganic
sodium chloride
- flavour
- food preservation
- role in food processing e.g. cheese and bread

Question 15

Carotenoids - ____
Chlorophyll - _____
Flavonoids - _____

Answer 15

carotene, lycopene and xanthophyll
a & b
anthocyanins, anthoxanthins and betalains

Question 16

Carotenoids:
______ affects the colour of plant foods

exposure to ____ also causes _____ of pigments and a resulting loss in colour

vegetables containing b-carotene should not be _____

Answer 16

heat

oxygen
oxidation

overheated

Question 17

Chlorophyll:
- pigment responsible for ____ colour of plants
- essential for _______
- _________ enhances the _____ colour by removing the air bubbles which may cloud the colour
- not very ____ need to: keep heating times ____ and heat food _____ initially to allow for the escape of _____ organic acids
- dull olive brown when overcooked comes from the ____ coming into contact with the _______ as the membranes are disrupted

Answer 17

green

photosynthesis

blanching
green

stable
short
uncovered
volatile

acid
chloroplasts

Question 18

Pigment that is responsible for the colour of the following:
cauliflower
kale
tomatoes
pineapple
beetroot
pumpkin
zucchini

Answer 18

• anthoxanthin
• chlorophyll
• lycopene
• xanthophyll
• betalains
• carotene
• anythocyanins

Question 19

what factors will reduce the water activity of food?

Answer 19

Addition of sugar
Addition of salt
Sun-drying
Baking

Question 20

what food chemistry reactions involves water as a key function

Answer 20

hydrolysis
salt formation
condensation
carbon dioxide release from baking soda

Question 21

which of the following factors will lead to an increase in the boiling point of water?
addition of sugar
boiling water at a higher elevation
addition of more heat
use of a slow cooker

Answer 21

addition of water