Page 12 - Horticulture Practical Guide

Spoilage of Fruits and Vegetables and Different Methods of

Preservation

The spoilage in fruits and vegetables is natural and occurs mainly due to the following reasons:-

(i) Activities of enzymes present in the fruits and vegetables
(ii) Growth of micro organisms.
Enzymes are complex chemical substances, present in all living organisms and tissues. These can
be permanently inactivated by extra heat (High temperature)
Micro-organisms are minute organisms, which are invisible to the naked eyes but can be seen through
microscope and are present in all normal surroundings. The important micro-organisms which are
responsible for the spoilage of fruits and vegetables are bacteria, yeast and moulds.

To check the activities of enzymes and the multiplication of these micro-organisms or to make them
inactive or functionless, following methods are adopted which are called as methods of preservation.
1) By application of heat i.e. (i) Pasteurization or (ii) sterilization.
2) By drying or dehydration.

3) By low temperature or by freezing
4) By use of
(I) permitted chemical preservatives viz (a) Sodium Benzoate (b) Potassium Meta-Bisulphite(KMS)
(ii) Acetic Acid (iii) Salt (iv) Sugar (v) Carbonation and (vi) Oil & spices.

Main Points to be Considered During

Processing of Fruit and Vegetables

1. Select fresh sound fruit and vegetables without damages and blemishes. These will yield good
quality products.

2. Before processing, wash the fruit and vegetables with running tap water to remove any adhering.
3. Avoid metal containers like copper, brass, iron etc. during processing, to avoid reaction of these
metals with fruit acids. Stainless steel, wooden or aluminum containers/equipments can be used.
4. Use chemical preservatives as recommended.

5. Only permitted edible food colours should be used, if necessary, and should be added towards the
end of the process. The maximum limit of any permitted colour to any fruit product should not
exceed 0.2gm per kg of the nal fruit products for consumption.

6. Only clean sterilized and dry bottles/Jars should be used as containers.
7. Use peeler instead of knife to remove skin of fruit/vegetables as it helps to remove a very thin layer
of skin.
8. Use enough water for cooking.
9. Cook vegetables covered on a low lame to reduce losses of nutrients.

3