Topic 2: Part B Flashcards
Food processing
conversion of raw plant and animal tissue into convenient and practical forms for consumption
Basic principles of food processing to achieve preservation include
- moisture removal
- heat treatment
Moisture removal
removing biological active water in an attempt to stop microorganism growth
Heat treatment
pasteurization, blanching, canning, baking, cooking, sterilization
Low temp treatment
cold storage
Acidity control
controlling pH of the food by adding an acidulate
Traditional non thermal processing
through chemical additives or food processing
Non thermal processing innovations
irradiation, high pressure
Food processing aids
specific food additives like gums, natural colouring agents, enzymes and sweeteners
Food spoils because of
microbiological, chemical, physical or enzyme induced decay
Decrease in food losses is achieved mainly by..
food preservation and food additives
Food preservation is the use of specific processing techniques to…
reduce spoilage microorganisms in food to improve safety and shelf life
Biologically active water in tissues is one of the;;
primary causes of food spoilage.
Food with a high aw.. and foods with low aw..
- deteriorate quickly,
- can be stored for extended periods
Other major causes of spoilage
- biological changes: growth of microorganisms
- chemical changes: oxidation or enzyme reactions
- physical changes: separation of water and oil that can occur in foods like mayo/yougurt as they age
3 main classes of food preservation
- chemical: addition of salt, sugar or chemical preservation
- biological: fermentation
- physical: drying, heating, cooling, irradiation
Chemical food preservation
addition of sugar, salt, or chemical preservatives to reduce food spoilage. salt and other preservatives such as potassium sorbet lower the water activity in foods.
Preservatives
additives that maintain the freshness of a food
Biological food preservation
fermentation lowers the pH of the food product, resulting in taste changes. encourages growth of friendly bacteria which can inhibit growth of pathogenic bacteria.
Salt or vinegar may be added to control…
bacterial growth during fermentation
Fermentation
preservation technique that involves bacteria or yeast acting on the carbohydrates of a food
Physical
- drying
- thermal processing
- cooling
- irradiation
Drying
involved removal of water form the food. the food is preserved because of microorganisms cannot survive in dry habitat. in ancient times drying was done predominantly by sun
4 ways of drying
- oven/plate drying
- spray drying
- drum drying
- freeze drying