India, a place of variations of different agroclimatic regions, rich in diversified horticultural flora. India being the largest producer of fruits and second largest producer of vegetables. But unfortunately the average Indian remains aloof from the basic requirements of fruits and vegetables. As a result of which there is a huge gap between gross production and net availability.
All these is because of the inefficient post harvest management ,a significant portion of production is lost after harvest. Post harvest losses accounts to approximately 25 – 30 % of production. Just to feed the bursting population of india, maximising alone the production and productivity will not be enough. Efficient post harvest handling and processing is mere essential to make available more food (fruits) to the mankind.
Post harvest losses of fruits:
Post harvest losses of fruits can be defined as a loss in quantity or quality or both that occurs after harvest and till the produce reaches to the consumers. There may be physical loss, physiological loss or biological losses.
Physical loss: it occurs due to injury in fruits at the time of harvesting,handling and transportation.
Physiological loss: it occurs due to physiological processes of respiration and transpiration. Transpirational loss of moisture results in shriveled appearance of the commodities.
Biological losses: it occurs due to macrobiological and microbiological agents like bacteria, fungi ,yeast etc.
Post harvest management practices:
Sorting or grading:
Sorting is done in order to discard rotten, damaged, diseased, misshaped and overriped fruits before spreading infection to other healthy commodities.
Grading is a form of grouping the fruits according to the firmness, cleanliness, size, weight, colour, shape and maturity.
The produce is cleaned or washed in order to remove the dirt, dust ,insects, moulds .exception – onion, garlic, okra, mushroom are not washed. For surface decontamination , Chlorinated water(100 ppm) is effective.after this,the fruits are again washed with clean water.
Curing is a means of natural wound healing process. It is a process of forming a corky layer against water loss and infection.
It is a process of application of waxy layer on the skin of the fruits to reduce moisture loss, shrievelling and to extend the storage life. Paraffin wax, carnauba wax and various resins are common types of waxes used. Waxol is a common coating material.
The process of removal of heat from the just harvested fruits particularly during hot weather is called pre cooling. It helps in decreasing the transpiration rate, respiration rate,ripening providing an ease to transport and storage. The methods are room cooling, forced air cooling, hydro cooling, vacuum cooling etc.
Hot water treatment:
It is a process of eradicating or killing the infectious organism on several fruits. For inactivation of infection by Phytopthora sp. In tomato and oranges , Colletotrichum in papaya, mango and crown rot in banana , dip in hot water at 50+- 2degree C for 1-2 minutes. Hot water treatment of mango results in uniform ripening.
Vapour heat treatment:
It is termed as an ecofriendly treatment mostly applicable for fruit flies mostly mango. It is initially expensive and cannot be used much by small and marginal farmers. Total treatment time for mangoes is approximately 195 minutes.
Regulation of ripening:
Ripening of fruits like mango, banana can be regulated or is carried out in special treatment rooms with controlled temperatures with low application of ethylene. Release of ethylene occurs where fruits along with etherel alkaline solution is placed in a closed chamber. Ripening process is delayed and extension of shelf life is done by removing ethylene from storage atmosphere using ethylene absorbent.
Packaging is a process to assemble the produce into convenient units of handling and to protect the produce during distribution , storage and marketting. It is a means of prolonging the storage life. For packaging cushioning materials should be used.(paper shreds, paddy straw, thermocole). Packaging of fresh produce is done with bamboo baskets, sacks, wooden or plastic crates etc. corrugated fibre board(CFB)cartons being polar now a days for transport of fruits as they are of lighter weight and cheaper cost. Aseptic packaging, modified atmospheric packaging and controlled packaging are some new innovations of packaging.
It is a phase of movement of fruits from one place to another, performed by, means of rail,truck,airplane and ship.effective transportation doesnot help if there is no proper handling.in many developed countries pallets are used for trading of horticultural produce.
Fruits have a high degree of perishability so marketting problems are more in fruits. NHB(National horticultural board) provides good market intelligence service for horticultural products.NDDB, HOPCOM are few of marketting organizations for benefit of growers and consumers.
The process of maintaining life processes of fruits upto a required level till it reaches the consumers avoiding market glut is called storage.
Refrigerated storage – storage of perishable commodities at the lowest temperature without any chilling injury is refrigerated storage.it strongly retards moisture loss and spoilage by microorganisms.
Controlled or modified storage- it is a process of adjusting the atmospheric composition of air surrounding the fruits different from that of normal air. it involves reduction in O2 and elevation of CO2 concentrations.
Hypobaric storage- it is a form of storage in which the produce is stored in partial vacuum.it is maintained to the desired low pressure by vacuum pump. It is limited to high value crops.
Zero energy cool chamber- this zero energy cool chamber works on the principle of evaporative cooling using locally available materials like brick, sand and bamboo.as compared to surrounding atmosphere the temperature in the chamber is less.
Post harvest loss is even more serious than that of production loss. It is impossible to deny from complete protection of post harvest losses but it can be minimized to some extent by following some of the modern cultural,harvesting,handling,marketting and processing techniques. Thus it must be kept in mind that operationalization of improved post harvest technologies must be intensively developed in our country through technology refinement, industrial liasion so that we don’t face any productive losses and people can acquire nutrients from fruits to the most , as per requirements.
Name of the books – 1. Post harvest management of horticultural crops. – Edited by M.A. MIR, G.M. BEIGH, HAFIZA AHSAN QUAZI NISSAR AHMAD, H.R.NAIK,A.H. RATHER.
2. Basics of horticulture. Editor – K.V Peter. Chapter no. 11. Post harvest management of fruits and vegetables, page no 497-506.
Champ ,b.r ,highley ,E and Johnson ,G.I 1993. Post harvest handling of tropical fruits .proceedings of International conference held at Chiang mai,Thailand 19-13 july 1993.
Mitra ,S.K .1997. postharvest physiology and storage of tropical and subtropical fruits CAB international new york.
Salunkhe, D.K and Desai ,B.B 1984 post harvest biotechnology of fruits. Vol1 & 2 .CRC press, florida.
Rao , S.D .V 2004 pre storage treatment for minimisation of post harvest losses in fruits . training manual on minimisation of post harvest losses in fruits organised by IIHR, bangalore.