Starch degradation in buttercup squash (Cucurbita maxima).
Irving, D.E., Shingleton, G.J. and Hurst, P.L
Journal of the American Society for Horticultural Science. Volume 124, Number 6, Nov 1999. pp. 587-590.
1999
บทคัดย่อ
Extractable activities of alpha-amylase, beta-amylase, and starch phosphorylase were investigated in order to understand the mechanism of starch degradation in buttercup squash (Cucurbita maxima Duchesne ex Lam. 'Delica') with the ultimate goal of improving the conversion of starch into sweet sugars. During rapid starch synthesis (0 to 30 days after flowering), extractable activities of alpha-amylase and beta-amylase were low, but those of starch phosphorylase increased. After harvest, during ripening at 12 degrees C, or in fruit left in the field, activities of alpha-amylase and beta-amylase increased. Starch contained 20% to 25% amylose soon after starch synthesis was initiated and until 49 days after harvest irrespective of whether the crop remained in the field or in storage at 12 degrees C. Maltose concentrations were low prior to harvest, but levels increased during fruit ripening. Data suggest starch breakdown is hydrolytic in buttercup squash, with alpha-amylase being the primary enzyme responsible for initiating starch breakdown.