In order to select fruits fit for preservation purposes, knowledge of ripening process in fruits is essential. During ripening of fruit, fruit develops to its full size, the pulpy edible tissue becomes soft and tender, the colour of fruit changes, and the starch content changes to sugar giving a mild sweet flavour and full characteristic aroma of the fruit develops. Changes beyond this point cause spoilage and deterioration of texture and flavour.
Efficient selection of fruit involves consideration of size, grade and variety. Size and grade of fruit are major determinants of the economic value of preserved food product i.e. net edible portion of fruit available for use in making a preserved product. Fruits of lower grade are less expensive but the waste may compensate the price advantage. Each fruit has different varieties and each variety has its special characteristics. For example- some varieties are good for preservation while some are good only for eating. Fruit price is not always indicative of quality or its nutritive value.
Climacteric fruits are those which ripen after being picked whereas non-climacteric ones do not. Climacteric fruits include apricots, bananas, kiwi, peaches, pears, plums, watermelon, mangoes, figs and tomatoes etc. and these can be purchased when unripe. But non- climacteric fruits like apples, cherries, grapefruit, grapes, oranges, pineapple and strawberries etc. should be purchased when fully ripe.
- The quality of fresh fruits can be judged reasonably well by their external appearance. In purchasing fruits, it is necessary to learn to judge the appropriate size and colour for the kind and variety of fruit, as these are indicators of the high quality of the fruit and its maturity.
- Most fresh vegetables and fruits retain their freshness for a short time under ideal conditions of storage. Nutritive value of fruits and vegetables decreases over a period after harvest therefore, one should try to buy those that are fresh.
- Good quality fruits are the ones that are just ripe, crisp, fine and free from bruises. They should not show any signs of spoilage like presence of mould, wilting and limpness, discolouration and mushy texture, presence of insects and worms, overmature vegetables and damaged or bruised skin etc.
- One should select the fruit at its peak of maturity for its sweet preserved preparations. Fruits are selected in unripe state when salty preserved products are to be made.
- Fruits in season are generally cheaper than when not in season and are of better quality than the fruit sold out of season. It is therefore advisable to buy fruits which are in season, as the quality is high and the price low.
- Since the fruits deteriorate more rapidly after they have ripened, one should purchase the fruit in bulk only when he has adequate facilities for storage (preserving) of the surplus fruit. Few fruits like apples can be kept for long period of time but the duration involved in transportation from the place of growing to market should also be kept in mind.
- Bananas: should not have black spots on the skin and be free from bruises and slightly hard when purchased. They should be then allowed to ripen at room temperature, as fully ripe fruit is easily bruised even as you carry it home from the market. Shelf-life of green bananas is very short after ripening. Ripe fruit does not store well in the refrigerator, as the sugar to starch conversion is favoured at low temperature. Best eating quality of bananas has been reached when the solid yellow colour is specked with brown.
- Apples: Good apples are firm, crisp, well coloured and heavy. Each variety has its own characteristic colour and shape. Apples become mealy, have less flavour and taste, when stored too long. Hence, it is advisable to buy apples only in season. Small, tart fruits are suitable for making jelly, sauce and similar preserved foods.
- Grapes: should be plump, shiny, well coloured, firmly attached to stem, free from discolouration and bruises. They should not leak as it is sign of spoilage.
- Citrus fruits: include oranges, sweet limes (mausambi), grape fruits, lemons, etc. These are sorted according to size and the price decreases with the size. These are sold per dozen or per basket, and in some markets lemons are sold by weight. Citrus fruits which are bright and thin skinned, firm, rich in colour and heavy in relation to size are preferred, as these are likely to contain more juice. Dull, dry skin and spongy texture indicate aging and deteriorated eating quality. Also avoid decay, shown by cuts or skin punctures, soft spots, mould on the surface and punctures of the skin , and discoloured, weakened areas of skin around the stem end or button.
- Pears: should be selected when it is firm and already begun to soften to be reasonably sure that they will ripen satisfactorily. They should not be wilted or shrivelled with dull-appearing skin and slight weakening of the flesh near the stem, which indicates immaturity and such pears will not ripen. Also avoid spots on the sides or blossom ends of the pear, which means that corky tissue may be underneath.
- Pineapple: Select pineapple with bright golden yellow, orange-yellow, or reddish brown colour, depending on the variety, which is spread to 15 or 20 per cent of the fruit and are firm, plump, and heavy for their size, with fragrant aroma, and a very slight separation of the eyes or pips. The larger the fruit, the greater the proportion of edible flesh. They should be free from discoloured or soft spots, bruises and mouldiness.
- Plums and prunes: should be selected with a good colour for the variety, in a fairly firm to slightly soft stage of ripeness.
- Peaches: which are fairly firm, not too soft, having skin colour yellowish or at least creamy between the red areas should be selected.