Food Tingz

Question 1

Heating lipids

Answer 1

Smoke point: 200 fats 250 oils - decompose and glycerol separates from fatty acid + broken down to a role in (blue smoke)

Flash point: 310 data 325 oils extreme overheating vapour emmited, spontaneously ignite

Melting point: solids melt 30-40

Question 2

Dextrinisation

Answer 2

Heated
Short chained polysaccharides (de grind) -> long chained pyrodextrins
= brown colour change (toast)

Question 3

Gelatinisation

Answer 3

Starch and liquid and heat at 55-70
Grains swell, burst, absorb liquid
Increases viscosity, Sol at 85
Gel= cools and water becomes trapped 
Eg. Roux

Question 4

Gel formation

Answer 4

Collagen + heat = gelatine, absorbs water when heated

Chains uncoil and water traps = sol eg. Cheesecake

Question 5

Hydrogenated

Answer 5

Hydrogen gas in presence of nickel catalyst is forced through double bond of unsat oil -> solid saturated fat eg. Margarine

Question 6

Emulsions/emulsifiers

Answer 6

A colloidal solution formed when two immiscabke liquids are forced to mix together eg. Water in oil
Permanent or not
Hydrophilic head phobic tail eg. Leicithin

Question 7

Protein denaturing

Answer 7

Change in nature of protein (eg unfolding chains irreversible shape change) caused by physical/chemical changes resulting in hardening/setting

Heat: unfold&bond=coagulate
Chemical: change pH
Mechanical: partial coagulation from unfolding
Enzymes: changes protein structure

Question 8

Spoilage of fish

Answer 8

Oxidative rancidity: oil in oily fish react with oxygen and combines with carbon in fatty acids = rancid smell

Enzymes: nationally present, deteriorate, low temp slows

Bacterial: little glycogen from struggle converts to lactic acid so deteriorates rapidly + nitrogen compound smell

Question 9

Stabilisers

Answer 9

Long chained molecules maintain emulsions by separating droplets and prevents coalesion eg. ICECREAM