Hi, I am current stuck on an assignment that is related to the comparison of the food preservation process canning and freezing. We have to write on the reasons for preserving, causes of food spoilage, principles behind food preservation techniques and description of the preservation processes.
Any help would be gladly appreciated!
Cheers!
Hey Cutiepie! I'm sorry for the delayed response - I was out at a camp with minimal internet access!
As for your assignment - do you know which food item you are doing it on yet? If you must do a vegetable, I would recommend peas. Otherwise, pears are also a pretty diverse option.
You would be a lot better off in this topic if you memorised your reasons for preservation, causes of spoilage and principles. It seems like a lot right now, although if you start memorising now you should be fine for the HSC examinations!
Here is a brief outline:
Reasons:
- Keep safe for human consumption (main)
- Avoid wastage
- Retain nutritional value of food
- Make perishable foods available year round (main)
- Achieve economic viability for producers by reducing seasonal fluctuations
Causes: 5 - MUST LEARN THESE!!!
- Physical: transportation and distribution/storage conditions; bruised fruit, freezer burn
- Chemical: chemical breakdown; rancidity in milk
- Enzymatic: ripening; softening of bananas
- Environmental: will cause physical + chemical changes; rats chewing through packaging, direct light causing colour changes
- Microbial: yeast, mould, bacteria, fungi in food or environment; mouldy cheese
Principles: 5 - MUST LEARN THESE!!!
- Water availability
- Temperature (remember to avoid the danger zone of 5-60 degrees Celsius)
- pH levels
- Oxygen levels
- Addition of chemicals
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So in terms of canning (both conventional and aseptic) peas, for instance:
Principles:
- Air tight sealed container excludes air, and prevents micro-organisms from re-entering the environment
- Heating of the food and container will destroy most micro-organisms and enzymes
>involves both cooking and vacuum packing
Looking at temperature directly:
- Cans and food heated to extremely high temps to kill micro organisms
- Cooled quickly to (a) prevent overcooking (which may reduce aesthetic appeal, texture, and nutritional content); (b) ensure that the food does not hover in the danger zone
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Just a quick and disorganised overview to help to job your mind. I don't have your criteria, so I'm not entirely sure as to the depth that you need to go into or analyse - but I would imagine that you would be engaged in some kind of discussion between the two principles. Feel free to shoot anymore questions our way!