Post-harvest biotechnology of fruits with special reference to banana— Perspective and scope

Fruits, being highly nutritive, are important component of human diet but they possess very short post-harvest shelf life. As ripen, they become very soft and more prone to injuries, which makes them highly perishable. In India, over 30% of the annual produce is wasted due to spoilage. Hence, there is an urgent need to develop technologies to overcome postharvest losses of fruits. Physiologists and biochemists attempted to extend the shelf life of fruits by different means though the results were not very satisfying. It was demonstrated recently that a judicious dose of γ-irradiation (0.1-0.5 kGy) could enhance the shelf life to fruits by about a week to a fortnight, which could help in minimising the spoilage during storage and transportation. However, stringent quality controls have to be strictly followed to get the best results. Studies revealed that γ-irradiation brings alterations/changes in metabolic pathways, which delay the production of essential precursors and energy required for ripening of fruits. Another strategy, to enhance the shelf life of fruits, could be adopted through regulation of endogenous ethylene production. Most recent studies have shown that it could be achieved by such genetically modified (GM) crops where gene expression of key enzymes responsible for ripening, like PG-ase, EFE and ACC-synthase, by means of antisense RNAs. However, adoption of this technology has so far been deterred due to apprehensions of safety issues associated with GM crops. An alternate method for prevention of spoilage of fruits as well as sustaining the interests in farmers could be the value addition of fruit commodities. This could be achieved by improving the conventional methods as well as development of non-conventional products of commercial interest. Nuclear Agriculture and Biotechnology Division, BARC has developed processes for the production of juice and powder from ripe banana, the largest produced and maximum wasted fruit, by creating an in-built mechanism to inactivate the pectin forming enzymes. With this process, over 60-80 % of the total moisture of the fruit is extracted out as juice. The commercially available variety, ‘Harichal’ (Mumbai kela) could give juice 550-640 ml /kg pulp. It is also demonstrated that a number of products of commercial significance, like banana nectar, carbonated juice and wine, from banana juice and biscuits, cakes, milkshakes, etc. from banana powder could be developed.