부산대학교 도서관

Alpha-amylase activities and activity gel profiles were measured in kiwifruit Actinidia deliciosavar. deliciosa([A. Chev.], C. F. Liang and Ferguson cv. Hayward) during fruit development and postharvest ripening. As fruit developed, alpha-amylase activity increased on a per fruit basis, mirroring the increase in starch content in the fruit. Alpha-amylase activity increased approximately 2-fold between 134 days after anthesis (DAA), (when fruit starch content is at its maximum before beginning to decline) and harvest. During postharvest ripening with and without ethylene treatment at 20 °C, or during postharvest storage at 0 °C, enzyme activity remained similar to harvest values until fruit were ripe and most of the starch converted to sugars. At this point activity decreased 4–5-fold. Several amylolytic bands as well as starch phosphorylase and debranching enzyme were visible in starch activity gels. Starch phosphorylase was lower in ripe fruit, as was the intensity of two amylolytic bands. None of the other amylolytic bands or the deb ranching enzyme changed in response to fruit development or ripening. The same results occurred if gels were incubated at pH 6.1 or pH 8.0. These results are discussed in relation to the initiation of net starch degradation at the commencement of fruit ripening.