Chapter 9 - Food Processing Flashcards
Why is food processed?
- Micro-organisms are killed
- Prevents waste
- Food is easy to transport and store
What are the methods of food preservation?
- Freezing: Very low temperatures are used - Water to Ice
- Drying: Moisture is removed
- Pasteurisation: Milk heated and rapidly cooled to kill bacteria
What is quick freezing?
Quick freezing forms very ver small ice crystals on food which helps keep the food firm when it thaws
What is slow freezing?
Slow freezing forms large crystals in food. When food is thawed, food becomes soft and all nutrients are lost.
What is blast freezing?
Blast freezing is carried out commercially at -30*C. This is the best form of freezing because cell walls are not damaged.
What are the guidelines for freezing?
- Use fresh good-quality food
- Chill food before freezing
- Use the fast freeze section of the freezer
What are the guidelines for packaging for the freezer?
- Should be moisture-proof and vapour-proof
- Seal bags with with wire ties or freezer tape
- É move as much air as possible
What are the guidelines for freezing veg?
- Prepare veg as for cooking
- Chill the veg in cool water
- Open freeze veg that stick together e.g. Peas
What are the guidelines for freezing fruit?
- Freeze ASAP after picking
- Prepare as for cooking
- Label all fruit carefully
What are the guidelines for freezing bread, cakes and pastries?
- Freeze either raw or cooked
- Use breads and scones within a month of freezing
- Ack in freezer bags, seal and label.
What are the guidelines for freezing meats?
- Trim away visible fat
- Separate burgers, chops and steaks using waxed paper
- Remove as much air as possible before freezing
What are the guidelines for freezing stews and casseroles?
- Make the sauce a bit thinner
- Shorten cooking time by 20mins to allow reheating
- Allow headspace for expansion
What are the guidelines for buying frozen foods?
- The temperature of the freezers should be -18*C
- Food should be frozen solid
- Check the expiry date
What are the guidelines for thawing frozen foods?
- Follow the thawing instructions
- Thaw overnight in the fridge, thoroughly
- Do not refreeze unless it is cooked thoroughly first
What are the advantages of using a freezer?
- Bulk buying, which saves money
- Food is available out of season
- Freezing contains colour, flavour & texture
What happens in the process of canning?
Heat destroys micro-organisms and food is kept in airtight cans to protect from contamination from micro-organisms.
What should you do when buying canned foods?
- Avoid bulging, dented or rusted cans (food poisoning)
- Read label to check contents. Fish may be in oil, brine or sauce. Fruit may be in a syrup
- Check expiry date
What happens in the process of drying?
Heat removes the water from food which prevents the growth of micro-organisms (no moisture).
What should you look for when buying dried foods?
- The packet should be intact
- Check expiry date
What happens during the process of irradiation?
Energy waves are passed through food, so micro-organisms are killed. The food keeps for long.
Compare frozen, canned and dried foods.
Frozen: Don’t loose vits & mins; don’t loose colour; flavour retained; don’t become too soft
Canned: Vitamins destroyed; colour lost; some flavour lost; fruit & veg softer
Dried: Vitamins destroyed; some colour lost and change shape; some flavour lost; texture changes
What are additives?
Food additives are substances added to food by manufacturers in order to improve the food in some way.
What are the functions of additives?
- Improve the appearance and flavour of food
- Make food last longer
- Reduce the risk of food poisoning
- Improve the texture of food
- Improve the food value of foods e.g. Nutritive Values
What are E-Numbers?
An E-Number member means that the additive has been tested by experts and has been accepted as safe by the EU. Under EU law, food additives and must be sited on food labels.
