Effect of gamma radiation on the ripening and levels of bioactive amines in bananas cv. Prata

Abstract

Green Prata bananas at the full three-quarter stage were exposed to gamma radiation at doses of 0.0 (control), 1.0, 1.5 and 2.0kGy and stored at 16±1°C and 85% relative humidity. Samples were collected periodically and analyzed for peel color, pulp-to-peel ratio and levels of starch, soluble sugars and bioactive amines. Degradation of starch and formation of fructose and glucose followed first- and zero-order kinetics, respectively. Higher irradiation doses caused increased inhibitory effect on starch degradation and glucose formation. However, doses of 1.5 and 2.0kGy caused browning of the peel, making the fruit unacceptable. Irradiation at 1.0kGy was the most promising dose: it did not affect peel color, the pulp-to-peel ratio or the levels of the amines spermidine, serotonin and putrescine. However, it slowed down starch degradation and the formation and accumulation of fructose and glucose, delaying the ripening of the fruit for 7 days.