UNIT 2 : Oxidation of Food Flashcards
When can the oxidation of food occur?
When food is exposed to the oxygen in the air
What happens to food when it is oxidised?
Deterioration of flavour Loss of colour Rancidity Loss of nutritional value Health risks from the toxic oxidation products
What is produced when the fat decomposes and reacts with oxygen?
Chemicals called peroxides are produced
What is used to prevent the formation of peroxides and stop food from “going off”?
Anti-oxidants
How do some anti-oxidants work?
By reacting with the oxygen itself
What types of food are at most risk of oxidation?
Foods containing fats and oils
What are free radicals?
A highly reactive species of molecule containing an unpaired electron
What part of the carbon chain does the oxygen attack?
The double bonds
What is left behind after the oxidation of food?
Free radicals
How do free radicals damage food?
The removal of an electron
How do anti-oxidants work?
They “mop-up” any free radicals to protect the food stuffs
What is the difference between free radicals and anti-oxidants in terms of electron shell?
Free radicals have a missing electron
Anti-oxidants have a full electron arrangement (no missing electrons)
What is the difference between free radicals and anti-oxidants in terms of size of the molecule?
Free radical molecules are very small
Anti-oxidants are much larger
What is significant about the difference in size between free radicals and anti-oxidants?
Even though, when an anti-oxidant donates an electron it becomes unstable, its instability is much less serious than that of a free radical as it is much larger
How does a free radical become stable?
An anti-oxidant donates an electron
