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FOOD PRESERVATION ( food technology)
1. SUBMITTED BY :
SAURABH VERMA
MSc.(biotechnology)
SEMESTER – IV
B.B.A.U., LKO(U.P.)
SUBMITTED TO :
Dr.MONICA SHARMA
Asst. PROFESSOR
B.B.A.U. , LKO(U.P.)
2. WHAT IS FOOD PRESERVATION ?
Retaining food over a period of time without
being contaminated by pathogenic organisms
or chemicals and without losing its colour,
texture, flavour and nutritious value.
Besides making the food lasts
longer, preservation also prevents
food wastage.
3. WHY DO WE NEED TO PRESERVE FOOD ?
So that surplus foods from good harvests
can be stored and then used in time of shortage
.
So that we can enjoy seasonal fruits and
vegetables all year round.
To enable it to be transported long distances
without it decaying.
To allow it to be stored in the home for long
period without getting rotten .
5. Bottling and canning are processes of
preserving food by heating and then
sealing it in an airtight container.
The food is boiled to kill
microorganisms and then sealed to
prevent other microorganisms from
getting in.
6. Pickling food in vinegar or other
acids, makes it difficult for
microorganisms to live. Commonly
pickled food include
onions, parkias, soya beans and
chillies.
7. Sugar can also be used in pickling
fruits such as nutmegs, mangoes and
cherries.
The concentrated sugar solution used
draws water from the fruit thus
preventing the growth of
Microorganisms .
8. Salting is an age-old way of
preserving food. The salt draws
out moisture and prevents
microorganisms from growing. In
this process, food such as fresh
fish are gutted, washed and
coarse salt is rubbed into it.
9. A lot of our local foods are
preserved by salting process.
10. Foods are prepared and then packed into a pouch
or foil wrapper and the air is sucked out, forming a
vacuum inside the pack.
Removing air takes away oxygen and moisture
which bacteria require in order to survive and
multiply.
11. Some vacuum packs can be stored at ambient
temperatures e.g. coffee and have a medium shelf
life. Others stored at chill temperatures e.g. smoked
fish, cheese and cured meats. These have a short
shelf life.
Organoleptic qualities are often well maintained
using this method.
12. Waxing of fruit and vegetables is also common.
Apples, oranges, eggplants and tomatoes are
dipped into liqiud wax to prevent growth of
fungi and loss of moisture.
Waxed fruit need to be washed thoroughly or
peeled before eating.
13. Smoking is the process of drying food with
smoke for a long period of time. This
method is mainly used for fish, meat and
fruit such as banana.
The drying effects of smoke and the
chemicals produced from the smoke help
to preserve the food.
14.
15. Pasteurization means heating food to
a certain temperature for some time
followed by rapid cooling. Heating
at such high enough temperature
kills most bacteria. However, it does
not affect the taste and nutritional
value of the food.
16. Fresh milk, yoghurt drink and juices are
pasteurized to make them last longer.
17. A lot of food is preserved by drying
under the sun.
Drying removes most water from food.
Most bacteria die or become
inactive when the food is dried.
18. Cooling and freezing are the most
common forms of food
preservation.
Cooling slows down the action of
microorganisms, thus it takes
longer to spoil. It allows fruit from
different parts of the world to
appear on our supermarket shelves.
19. Food like meat, fruit and vegetables are kept
in the refrigerator.
21. 1.Exposing food to gamma rays,x-rays,to improve shelf life and safety
2.When food is irradiated ,the radiation energy break the bonds in the
Dna molecule of microbes . Thus the organism dies or unable to reproduce.
3.Frozen foods takes larger radiation dose to kill microbes.
4.The effectiveness of the process depends on the organisms senstivity
To irradiation.