A STUDY OF THE PHYSIOLOGICAL-CHANGES AND THE NUTRITIONAL QUALITIES OFIRRADIATED APPLES AND THE EFFECT OF IRRADIATION ON APPLES STORED AT ROOM-TEMPERATURE

The effects of gamma-irradiation on the metabolism and nutritional qua lities of Gold Delicious apples and on the lethality of verticillate p athogenic fungi have been studied. The storage effect of irradiation o n apples at room temperature has been observed. The results showed tha t the respiratory intensity of irradiated apple at 0.3-0.5 kGy was nea r or lower than that of unirradiated apple after 15 days irradiation. The amount of ethylene release was obviously inhibited when fruits wer e irradiated with 0.3-0.7 kGy. The flesh firmness of apple irradiated with 0.3-0.9 kGy was higher than that of unirradiated apple with the i ncreasing of storage time. The negative correlations between the flesh firmness and the activities of pectinesterase (PE). polygalacturonase (PG) were observed when the dosage was lower than 1.5 kGy. The 2.0 kG y irradiation damaged the ultrastructure of cells, induced the softeni ng of apple. when apples were irradiated with 0.7-2.0 kGy, the content s of 4 important volatile components of apple would be decreased. Howe ver, the dosage mentioned above had no effects on the pure chemicals. The studies showed that there was no significant effect of irradiation with 0.3-2.0 kGy on the nutritional qualities of apples and this dosa ge range could effectively control the verticillate pathogenic fungi. The result of storage experiments showed that the rotting fruits were obviously decreased by 0.3-0.9 kGy irradiation.