09 November 2011

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Understanding Food Preservation

Understanding Food Preservation

Foods get spoilt mainly due to the presence of micro organisms, enzymes (present in foods), insects, worms, and rats.

What is Food Preservation?

Preserve means
1. to prevent from decomposition or chemical change

2. to protect from decay or dissolution

3. to prepare (food), as by freezing, drying, or salting, so that it will resist decomposition

4. keep safe - food, vegetables

5. retain quality

6. prevent decomposition or fermentation

Now let us apply this to the Food Preservation –

Food Preservation can be defined as
A process by which certain foods like fruits and vegetables are pre-vented from getting spoilt for a long period of time.
The color, taste and nutritive value of the food is also preserved.

Meaning of Spoilt –
spoilt - (of food ) not in an edible or usable condition; "

The definition says preventing
foods from getting spoilt. When you keep fruits, vegetables or left over food in the
refrigerator or in a cool place, will this be called food preservation?

No it’s not Food Preservation. By using above methods we can keep the fruits only for few days.

Food Preservation means keeping the food safe and good condition for the long period of times.

The definition of food preservation states that the preserved food should retain their
colour and taste.

This means that the colour and taste of food which is present at the time of preservation should not change.

Let us take the example of preserving grapes as raisins. Raisins are prepared by sun drying grapes. During the drying process the grapes change colour from green to brown, and taste, sweeter. However, once they are dried and stored, they do not change colour or taste.

Why to Preserve Food?

1. To save excess produce

2. To Get the taste all over the year as many fruits are seasonal like Mango

3. Once we Preserve the food that food can be enjoyed by everyone in the world if he is ready to pay – Can be Enjoyed by citizens of any country even if that fruit is not grown in that city

4. Makes Transportation Easy

5. Makes Storage Easy

How to Preserve Methi?

1. Wash methi and remove the stems.

2. Put on a cloth in the sun, cover it.

3. Cool to room temperature and store in air tight tins

Making Potato chips –

1. Wash and peel potatoes. Cut in thin round slices.

2. Put in boiling water for 3-4 minutes.

3. Make a solution in cold water with 4 tsp salt, ¾ tsp potassium metabisulphite
(for 4 kg potato).

4. Put the blanched potato chips in this solution for 10 minutes.

5. Spread each chip separately on a plate in the sun. Cover with a thin cloth.

6. When dry, cool and store in air tight containers

What are preservatives?

Any substance that is added to foods to make it last for a longer time is called a

There are two types of preservatives:-

(1) Natural Preservatives: Salt, sugar, lemon juice, vinegar, oil and spices are natural

(2) Chemical preservatives: Potassium metabisulphate, citric acid and sodium ben-zoate are chemical preservatives.

Salt is used as a preservative in pickles, chatni, sauce, canned food, etc. Salt is
rubbed on fish which helps to preserve it

Vinegar is used to preserve onions, tomato ketchup; lemon juice is used in pickles;
citric acid is used in squashes.

When you plan to preserve food –
Use Clean utensils and containers with air tight lid.
Preserving Pickle - Final Layer should be Oil so there will be no air contact

Using Frozen Vegetables –

1. Take out the frozen packet from the freezer one and a half hours or two hours
before use and let it thaw to room temperature. Put peas in a sieve and keep
under tap water for a few minutes. Drain and use.

2. Frozen vegetables can be stored up to six months in a freezer.

The food once brought out of the freezer and up to room temperature should not
be refrozen.

Reality views by sm –

Wednesday, November 09, 2011

Tags – Food Preservation


Kirti November 10, 2011  

The best preservation technique is from our very own desi DRDO.
Cook food, prepare juices in an 100% bacteria free environment. Pack it in bacteria free metallic foils without any scope for air to enter.That's all.

Amrit November 10, 2011  

An excellent post

sm,  November 10, 2011  


Usha November 28, 2011  

sm, Very nice informative post on food preservation...reminded me of time when we used to do home made sun dried potato chips in big batches to last for one full year. Now building terrace is all empty year round..nobody store any thing.
Freezing food needs delicate handling and wrong refrigeration will never ensure safe food.
Recently Indian grocery stores have more frozen and packed cooked food which is not always safe to eat because it travels all the way from India and is likely to miss refrigeration at some point but consumption is going up because it is cheap and some traditional dishes do taste very good.
Here in USA people seriously preserve excess produce and cooked food. Super market frozen veggies are more fresher,vibrant and come in variety..they bring lot of ease in cooking.
Thanks for this post.