Effect of gamma irradiation on the postharvest physiology of five banana varieties grown in India

Abstract

Gamma irradiation to 20-40 krad inhibits the ripening changes in preclimacteric bananas without affecting the fruit quality. Both fruit maturity at harvest and post-irradiation storage temperature markedly influence the response to irradiation. The optimum dose and the maximum tolerable dose varied among the five varieties screened. Ability of the banana fruit to withstand higher doses of gamma irradiation depends on the physiological status of the fruit at time of irradiation. Irrespective of varietal differences, irradiation of preclimacteric bananas to doses above 50 krad resulted in severe skin discoloration and fruit splitting. Irradiation under anoxia did not markedly reduce the radiation injury, suggesting that factors other than ozone formed during irradiation in air may contribute the radiation damage. Fruits on the climacteric could tolerate up to 200 krad but no effect on ripening rate was observed. Ethylene or 2,4-D could reverse irradiation-induced inhibition of ripening in bananas. Irradiation seems to decrease the sensitivity of banana fruit to the ripening action of exogenously added ethylene.