D-アラボアスコルビン酸存在下におけるL-アスコルビン酸の分解について(第2報) : 嫌気条件下における検討

概要

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Anaerobic decomposition of L-ascorbic acid in the presence of D-araboascorbic acid in aqueous solution was studied. Separation and determination of L-ascorbic acid and D-araboascorbic acid in their mixed aqueous solution were carried out by gas-liquid chromato-graphy. Anaerobic decomposition of L-ascorbic acid alone and D-araboascorbic acid alone was examined at various temperatures (40°, 50°, 65°) and pH values (pH 1.0-6.0). The pH-rate profile of the two compounds clearly showed a maximum at pH=pK_1 and the optimum pH for the stability was found to be pH 6.0. The shape of the pH-rate profile of L-ascorbic acid varied with temperature, but that of D-araboascorbic acid varied little with temperature. The present experimental data on anaerobic decomposition of L-ascorbic acid at 40°, 50°, and 65° were in good agreement with the theoretical values calculated from the equation proposed by Higuchi. From kinetics, it seemed reasonable to assume, also in the case of D-araboascorbic acid, the formation of a complex between undissociated araboascorbic acid and monohydrogen araboascorbate. The decomposition of L-ascorbic acid in the presence of D-araboascorbic acid was faster than that of L-ascorbic acid alone. The stabilizing effect of D-araboascorbic acid for the decomposition of L-ascorbic acid was not observed in the anaerobic aqueous solution.
公益社団法人日本薬学会の論文
1971-04-25