α-アミラーゼのα米溶解作用に及ぼす有機酸および塩の効果 : 清酒もろみにおける蒸し米の溶解機構(第1報)

概要

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Alphanized rice (steamed and dehydrated with alcohol) was digested with Aspergillus oryzae α-amylase in various organic acids (0.02M, pH 4.0) at 15℃. The digestion rate of alphanized rice differed remarkable depending on the organic acid : the rice was digested well in citrate buffer but not in lactate buffer. An inverse correlation was found between the dissociation constant(pK) of organic acid and the rice digestion rate. As the ionic strengh of the buffer solution was raised, the rice digestion rate and the concentration of free α-amylase in the solution increased. The rice digestion rate and the α-amylase adsorption to the rice were also affected by concentration of the organic acid as well as the pH. In the case of lactate buffer, α-amylase was completely adsorbed to the rice at pH 3.0-4.5. In the case of citrate burrer, the rice was well digested at the low concentration of 0.01M, whereas the rice digestion did not occur until above 0.1M in the case of lactate buffer. In conclusion, it was found that adsorption of α-amylase onto alphanized rice and rice digestion by α-amylase depended on the pK of organic acid used for buffer solution depended on the pH and ionic strength.
社団法人日本生物工学会の論文
1979-07-25