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

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 2.0 kGy 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 2.0 kGy caused browning of the peel, making the fruit unacceptable. Irradiation at 1.0 kGy 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.

► Gamma radiation affected biochemical and quality attributes of banana.
► Degradation of starch correlated negatively with gamma radiation dose.
► Banana irradiation at 1.0 kGy delayed ripening with minimal biochemical changes.
► Serotonin degraded at a faster rate during ripening of irradiated banana compared to control.
► Spermidine levels increased on the first 7 days of storage in irradiated samples.