酿造酱油氨基酸态氮含量和级别的快速检测

建立快速检测酿造酱油中氨基酸态氮含量和级别的方法。以GB 18186—2000《酿造酱油》中的相关数据为依据，以国产酱油为样品，以天然食用色素为呈色剂，根据等物质的量的反应原则，设定检测各级酱油产品所需的NaOH浓度和物质的量。结果表明：紫薯食用色素为红色、橙红色和橙灰色时，酱油为合格产品。该法操作简单、便捷，判断直观、准确、实用，取样后数分钟内即可获得检测结果，与GB 2009.235—2016《食品中氨基酸态氮的测定》对照测定氨基酸态氮的结果完全吻合。

Rapid Determination of Amino Acid Nitrogen Content of Brewed Soy Sauce for Grade Identification

A new method for quickly detecting the content of amino acid nitrogen in brewed soy sauce has been established for grade identification. Several Chinese brands of soy sauce were tested using natural food colorants as chromogenic agents according to the national standard GB 18186-2000 Fermented Soy Sauce. According to the law of conservation of mass, the concentration of NaOH and the amount of substances needed to detect all grades of soy sauce products were systematically investigated. The results showed that the purple sweet potato colorant exhibited red, orange-red or orange-gray colors for qualified soy sauce. The developed method was simple, convenient, intuitive, accurate, and practical, and took a few minutes to give results consistent with those from the national standard method GB 2009.235-2016 Detection of Amino Acid Nitrogen in Food.