Solubilization of starch by treatment of ann granules with alpha amylase an enzymatic method for determination of ruptured and damaged granules in ann samples part i
Kugimiya, M.; Hirata, T.
Journal of Japanese Society of Food Science and Technology 34(9): 581-585
Dried plain Adzuki Ann granules prepared from Adzuki bean (Vigna angularis) and samples prepared by grinding an aqueous suspension of the dried Adzuki Ann granules by a homogenizer were used as models of intact and ruptured Ann granules respectively. This paper describes a method to determine the proportion of ruptured granules in a standard Ann sample containing intact and ruptured granules in various ratios, by measuring the percentage of starch solubilized by .alpha.-amylase. The dried sample (24 mg) suspended in a buffer (pH 5.9) was allowed to react with .alpha.-amylase (1 unit) at 35.degree.C for 30 min. The suspension was then placed in a boiling water bath for 10 min, cooled and centrifuged, and the amount of starch solubilized was measured. The amount of starch solubilized by the treatment with HCl (0.25 N) instead of .alpha.-amylase was regarded as the total amount of starch in the sample. The percentage of starch solubilized by the .alpha.-amylase treatment was defined as the ratio of the amount of starch solubilized by the .alpha.-amylase treatment to that by the HCl treatment. It was found that the percentage of starch solubilized by the .alpha.-amylase treatment was about 2% for the intact granules and about 98% for the ruptured granules and increased linearly with a increasing proportion of ruptured granules in the standard Ann sample. The results suggest that the percentage of starch solubilized by the .alpha.-amylase treatment might be applied to the determination of ruptured and damaged granules in Ann samples.