Starch Transformation During Banana Ripening: The Amylase and Glucosidase Behavior

Banana starch disappearance during ripening originated at the central portion of the fruit radiating, afterwards, to the surface; the amylose/ amylopectin ratio remained constant during the process. The amylo-plast was investigated by light and scanning electron microscopy. The surface of starch granules was smooth, and the unique modification obsenred during ripening was the reduction of the granule dimensions; at advanced ripening stages, some striations were detected on the surface of both small and large granules. Several amylolytic enzymes were followed during banana ripening. Seven amylases were detected at all stages, presumably three a- and four p-amylases and, like glu-cosidases, their activity increased at the climacteric phase; only p-amylase activity increased before the onset of the respiratory peak. For the first time a-l, 6-glucosidase activity was detected in banana