Question

what is food preservation?explain any tow methods

Answer 1

Food preservation, any of a number of methods by which food is kept from spoilage after harvest or slaughter. ... Among the oldest methods of preservation are drying, refrigeration, and fermentation. Modern methods include canning, pasteurization, freezing, irradiation, and the addition of chemicals

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Answer 2

Answer:

Food preservation prevents the growth of microorganisms (such as yeasts) , or other microorganisms (although some methods work by introducing benign bacteria or fungi to the food) , and slowly the oxidation of fats that cause rancidity.

1. Addition of sugar: In this method sugar is added and then food is heated. This method is used for the preparation of jams, jellies and marmalades. Fruits like apples, mangoes, strawberries, etc are preserved by this method.
2. Addition of salt: Common salt has antimicrobial activity. Salt is added to food to control the growth of fungus and microorganisms. When salt is added bacterial cell loses water due to osmosis. Due to this, the cell either remains dormant or remains. This helps in storage of food. This method of preservation of food by addition of salt is called salting. It is used for preservation of fish products, meat and for the preparation of pickles of lemon, chillies, raw mangoes, etc. It is also used in the preservation of amla, beans, tamarind etc.