Biochemical studies on changes in quality of post-harvest fruits during storage, 3

Changes in metabolism related to gluconeogenesis during the process of chilling-injury in banana fruit were investigated using L-aspartic acid-14C (U) and L-serine-14C (U) solely as a substrate.In the fruits stored at 6°C for 6 to 9 days, incorporations of radioactivities into the sugar fraction after incubation with labelled amino acids were significantly higher than those of healthy fruit stored at 20°C, especially in the case of serine as a substrate.During the storage at 20°C after storage at 6°C for 9 days, incorporation of both amino acids into the sugar fraction decreased gradually, while the incorporation into the organic acid fraction rather increased.A drastic increase in incorporation of serine into ethanol fraction was noted in the chillinginjured fruit at 7 days after the storage at 20°C, and the pulp become to soften. At this time, activities of 3-phosphoglycerate dehydrogenase and serine dehydratase, which were concerned with serine metabolism, were 2 times as high as those of fruit stored at 6°C.From these results, metabolic pathway in chilling-injured banana fruits during the process of after-ripening was discussed.