Determination of Amino Acidity in Japanese Sake Based on the Voltammetric Measurement of Surplus Acid by Quinone Reduction (Supporting Information)

In this paper, we propose voltammetry for determining amino acidity in Japanese sake. The measurement principle of this voltammetric method is based on a concept of acid-base back titration and a decrease of cathodic prepeak current of 3,5-di-tert-butyl-1,2-benzoquinone (DBBQ) caused by surplus HCl, which is obtained by the neutralization between excess HCl and amino acids in Japanese sake. In the comparisons of amino acidities in Japanese sakes (n = 10) obtained by this voltammetric method and the official titration, called the ethanol additional method, the correlation coefficient (r) was 0.946, indicating that the amino acidities in Japanese sakes by both methods were essentially the same.

本研究提出一种用于测定日本清酒氨基酸酸度的伏安法（voltammetry）。该方法的测量原理基于酸碱返滴定思路，以及过量盐酸与日本清酒中氨基酸发生中和反应后剩余盐酸所引发的3,5-二叔丁基-1,2-苯醌（3,5-di-tert-butyl-1,2-benzoquinone，DBBQ）阴极预峰电流降低。针对n=10份日本清酒样品，将本伏安法测得的氨基酸酸度与官方采用的乙醇添加滴定法结果进行对比，二者的相关系数（r）为0.946，表明两种方法测得的日本清酒氨基酸酸度基本一致。