Food preservation Technology ppt
Food preservation Technology
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Food preservation is the process of treating and handling food to stop or greatly slow down spoilage (loss of quality, edibility or nutritive value) caused or accelerated by micro-organisms. Some methods, however, use benign Bacteria, yeast and fungi to add specific qualities and to preserve food (e.g., cheese, wine). Maintaining or creating nutritional value, texture and flavor is important in preserving its value as food. This is culturally dependent, as what qualifies as food fit for humans in one culture may not qualify in another culture.Preservation usually involves preventing the growth of bacteria, fungi, and other micro-organism, as well as retarding the oxidation of fat which cause rancidity. It also includes processes to inhibit natural ageing and discoloration that can occur during food preparation such as the enzymatic browning reaction in apples after they are cut. Some preservation methods require the food to be sealed after treatment to prevent recontamination with microbes; others, such as drying, allow food to be stored without any special containment for long periods.
Common methods of applying these processes include drying, spray drying, freeze drying, freezing, vacuum-packing, canning, and preserving in syrup, sugar crystallization, food irradiation and adding preservatives or inert gases such as carbon dioxide. Other methods that not only help to preserve food, but also add flavor, include pickling, salting, smoking preserving in syrup or alcohol, sugar crystallization and curing. Food preservation is the process of treating and handling food in a way that preserves its edibility and nutrition value. The main effort is to stop or greatly slow down spoilage to preventfoodborne illness (e.g. salting, cooling, cooking). However some methods utilize benign bacteria, yeasts or fungi to add specific qualities and to preserve food (e.g. cheese, wine). While maintaining or creating nutritional value, texture and flavor is important in preserving its value as food; Preservation usually involves preventing the growth of bacteria, fungi and other micro-organisms, as well as retarding the oxidation of fats which cause rancidity.
Food And Milk-:
1895, Lawes and Gilbert
Production In their comprehensive paper relating to the feeding of animals published in 1895, Lawes and Gilbert discussed amongst other questions that of milk production, and directed attention to the great difference in the demands made on the food-on the one hand for the production of meat (that is, of animal increase), and on the other for the production of milk . Not only, however, do cows of different breeds yield different quantities of milk, and milk of characteristically different composition, but individual animals of the same breed have very different milk-yielding capacity; and whatever the capacity of a cow may be, she has a maximum yield at one period of her lactation, which is followed by a gradual decline . Hence, in comparing the amounts of constituents stored up in the fattening increase of an ox with the amounts of the same constituents removed in the milk of a cow, it is necessary to assume a wide range of difference in the yield of milk .
Wash, and snap tender green beans (string if necessary). You can dry them whole, but it takes a lot longer, and I am impatient! Blanche the beans for 4 to 8 minutes, depending on the size of the beans. I usually end up with a mixture of different sizes, so I generally go with about 6 minutes of steam blanching. Cool the beans in a sink full of cold water for about 2 minutes, then spread them on a towel and pat them dry. Arrange them on your dehydrator trays in a single layer, and dry at 145 degrees for the first hour, then reduce the heat to 125 degrees until they are done. They will be brittle and crisp when dry. Depending on the size of the bean, mine usually take 8-16 hours to dry.
Whole Plant Method
When our growing season is short, I only get one or two pickings off the plants before it turns too hot for them to continue making. When this happens, I generally pull up the plants, beans still attached, and hang the whole plant, upside down, outside, until the beans are dry.
**A note about blanching: Being hard-headed, I thought, in the past, that blanching took a lot of time, and probably wasn't all that necessary. Ha! I ended up with a tougher end-product.