1. PRESERVATION OF FOOD
Food is preserved to prevent natural and microbiological decay!
Today food is preserved for these reasons:
1.to add variety to the diet
2.to make use of food when it is cheap and store for later
3.to vary the diet by preserving food in different ways
4.to save money, we do not need to buy extra food
Aims of preservation
Besides preventing decay, preservation also aims to retain these qualities:
Ø flavour
Ø texture
Ø color of food
Ø appearance
Ø nutritional value
removal of moisture
(germs need it to live) removal of air
(germs need it to live)
Methods of preservation
addition of a chemical preservative
reduction of temperature antioxidants
by refrigerator: reduce activity sodium chloride
by freezing: being dormant sulphur dioxide
acid-sugar
heating
sterilization
pasteurization
Ultra Heated Treatment (UHT)
Canning - bottling