The techniques for post-harvest handling of fruits and vegetables are divided in following sub-heads: 1. Harvesting of Fruits and Vegetables 2. Pre-Cooling 3. Waxing 4. Sizing/Grading 5. Packaging 6. Storage of Fruits and Vegetables 7. Transportation Methods 8. Safe Technique for Ripening of Fruit
Technique # 1. Harvesting of Fruits and Vegetables:
The parameters to judge the maturity of fruits and vegetables for harvesting are as under:
i. Color:
Color charts are used for determining the maturity of tomato, mango, peach, plum etc. For example, tomato for local market can be harvested when red ripe, for medium distance markets at pink stage and for distant markets at breaker stage.
ii. Firmness:
The degree of softness (firmness) can be measured/estimated with instrument known as Penetrometer. For determining the firmness of fruit, it is inserted inside the fruit with desirable force. The firmness of fruit decreases with ripening of fruits.
iii. Size and Shape:
Size and shape is a useful index for determining the harvest maturity of most of the fruits and vegetables. For example fullness of cheeks and roundness of shoulder are important maturity index for determining maturity of mangoes etc. Sizing rings with holes for specific sized produce can be easily be made from a thin piece of wood or strong plastic.
iv. TSS (Total Soluble Solids):
A hand held refractometer is used to measure TSS percentage in a small sample of fruit juice. A few drops of fruit juice are put inside refractometer to measure the sweetness of fruit. This instrument is a useful tool and can be used at the time of harvesting of fruits.
v. TSS/Add Ratio:
Knowing the sugar content alone is not enough to measure maturity and quality of citrus fruits and grapes. In these fruit, the ratio of sugar to acid content is a much better predictor for harvesting of high quality produce.
vi. Days from Full Bloom to Harvest:
Time period between full bloom and fruit maturity is quite constant in some crops like pear, mango, apple, and pomegranate. Therefore this parameter can be used for judging the harvesting period of these fruit. In some vegetable crops, time period from sowing/transplanting to maturity also serves as an indicator of harvesting and is practiced in some crops like watermelon, okra, bell pepper etc.
Do’s and dont’s for harvesting high quality produce:
i. Use sharp knives and clippers for harvesting of produce
ii. The fruit should never be harvested by pulling. It will lead to injury and disease infection at the point of attachment of fruit.
iii. Use cloth bags to collect the harvested fruit.
iv. The tripod ladder should be used for harvesting the fruit from high trees.
v. Harvesters should be trained to recognize the proper maturity stage for the produce such as size, shape, color and firmness etc.
Technique # 2. Pre-Cooling:
The harvested produce should immediately be cooled. It will help in increasing the shelf life of horticultural products. Depending upon the type of commodity to be pre-cooled, use appropriate cooling method such as room cooling, forced-air cooling and hydro-cooling.
Technique # 3. Waxing:
There is loss of water from the harvested produce during marketing, which affect the natural gloss and quality of the commodity. Therefore, in order to reduce this loss, the food grade wax should be applied on fruit and vegetable.
The application of wax coating has proved useful in capsicum, tomato, citrus (kinnow), apple and pear etc. The waxes approved by Food Safety Standard Authority of India (FSSAI) are Shellac wax, Carnauba wax and Bees wax.
Technique # 4. Sizing/Grading:
The produce should be graded after harvesting. The grading should be done as per the requirement of different markets. The produce can be graded according to its size, weight, colour etc. Selling of produce after doing necessary grading can fetch better profit to the farmers. At commercial scale, the fruits and vegetables are graded with the help of mechanical graders.
Technique # 5. Packaging:
Packaging of fruit and vegetable play an important role for their safe transportation.
The techniques for packaging of produce are as under:
i. Wooden Boxes:
Wooden boxes are used for distant transportation of fruit and vegetables such as apple, peach, plum, tomato. The paper shreds or pieces of cardboard paper should be used in these boxes during transportation in order to avoid bruising of produce.
ii.Wooden Basket:
These baskets are used for packaging of cauliflower, capsicum and leafy vegetables etc. for local marketing.
iii. Jute Sacks:
Jute sacks are usually used for packaging and marketing of potato and onion etc.
iv. Plastic Crates:
Plastic crates are used for packaging, storage and marketing of Kinnow, tomato, grapes etc.
v. Corrugated Fiber Board (CFB) Boxes:
These boxes are used for packaging of high value produce such as apple, mango, grapes, Kinnow, peach, plum, litchi etc. for safe transportation to distant markets (Fig 10.1).
vi. Shrink and Ding Film Packaging:
The fruit and vegetable are packed in paper tray and wrapped with shrink or cling film. The produce packed with this technique remains visible to the consumers. This technique also maintains the quality of packed produce. High value fruit and vegetable such as kinnow, tomato, capsicum, seedless cucumber etc. can be packed in shrink or cling film and marketed in retail markets for earning better profit (Fig 10.2).
Technique # 6. Storage of Fruits and Vegetables:
The produce should not be sold in the market when there is glut. The produce should be stored and once the glut is over, it should be sold. This way a good profit can be earned. The apple and potato can be stored for longer period of time.
The storage conditions for storage of Kinnow, potato and onion are as under:
Technique # 7. Transportation:
Carelessness at the time of transportation can lead to loss of produce. Vehicles can be padded or lined with a thick layer of straw in order to avoid the losses of produce during transportation. Heavy weight produce should not be loaded over soft produce.
Technique # 8. Safe Technique for Ripening of Fruit:
Generally, banana, papaya etc. are commercially ripened with harmful chemical “calcium carbide” which is known as masala. The consumption of such ripened fruit is harmful for health and sometimes may lead to blister in mouth and ulcer in stomach.
Therefore, the use of this chemical for ripening of fruit is banned by Government of India. At home scale, the fruit can be ripened by wrapping in the newspapers. The wrapped fruit should be packed in baskets and kept in ventilated rooms. The fruit are ripened and ready to eat in 4-5 days.
Ripening of Fruit with Ethylene Gas:
Ripening of fruit with ethylene gas is an internationally acceptable technique. In this technique the fruit are exposed to ethylene gas (100-150 ppm) in an enclosed chamber for 24 hours for triggering the ripening process. The temperature of the chamber is maintained at 15-25°C and relative humidity at 90-95%. The ethylene generator is used to produce the ethylene gas.