Properties of Lipids - Rancidity Flashcards
What is rancidity?
It is the term used to describe lipids when they ‘go off’ which results in an unpleasant odour and taste
How many types of rancidity is there?
There are two types
What are the two different types of rancidity?
Oxidative rancidity
Hydrolytic rancidity
How do you prevent rancidity in fats?
Store fats in the fridge
How do you prevent hydrolytic rancidity in oils?
Store oils in a cool dark place
How do manufacturers prevent rancidity?
They use an anti-oxidant to prevent fatty acids from going rancid
Where are antioxidants naturally found?
In vitamins A, C and E
Where are antioxidants artificially found
In BHA and BHT
Antioxidants are added into what types of foods to prevent rancidity?
(5)
Biscuits Cooking fats Dairy spreads Stock cubes Oil
What is oxidative rancidity?
This is a form of rancidity that occurs when oxygen (O2) is forced through the double bond of an unsaturated fatty acid
Give an example of where oxidative rancidity
Oil solidifying on a pan
What is hydrolytic rancidity?
A form of rancidity which occurs when enzymes and bacteria react with the lipid
What effect does hydrolytic rancidity have on a lipid?
It results in the breakdown of the triglyceride with the glycerol separating from the fatty acids which results in an altered flavour
Hydrolytic rancidity occurs in what types of fatty acids/
Saturated and unsaturated fatty acids
Give an example of where hydrolytic rancidity occurs?
Occurs most commonly in freezers as enzymes are not destroyed
