食品和饲料成分中含硫氨基酸的氧化和水解测定：协同研究。

Oxidation and hydrolysis determination of sulfur amino acids in food and feed ingredients: collaborative study.

作者信息

MacDonald J L, Krueger M W, Keller J H

出版信息

J Assoc Off Anal Chem. 1985 Sep-Oct;68(5):826-9.

Abstract

Samples of 6 food and feed ingredients and a purified protein, beta-lactoglobulin, were analyzed by 7 laboratories to determine the concentrations of cysteine as cysteic acid and methionine as methionine sulfone. Samples were oxidized by reaction with performic acid before hydrolysis with 6N HCl. The free amino acids were then separated and measured by ion-exchange chromatography on dedicated amino acid analyzers. Each laboratory was provided with a detailed method as well as sealed vials containing solutions of standards. For the determination of cysteine as cysteic acid, the coefficients of variation between laboratories for duplicate samples ranged from 7.13 to 10.8% for the 6 ingredients. For the determination of methionine as methionine sulfone, the coefficients of variation between laboratories for duplicate samples ranged from 1.18 to 12.8% for the 6 ingredients. Cysteine and methionine recoveries were determined by analysis of beta-lactoglobulin and were based on expected levels of each amino acid from amino acid sequence data. The mean recovery of cysteine was 95% with a range of 91-101%. The mean recovery of methionine was 101% with a range of 98-106%. This method has been adopted official first action.

摘要

6种食品和饲料成分样品以及一种纯化蛋白β-乳球蛋白，由7个实验室进行分析，以测定半胱氨酸（以半胱磺酸形式）和蛋氨酸（以甲硫氨酸砜形式）的浓度。样品在用6N盐酸水解前，先与过甲酸反应进行氧化。然后通过专用氨基酸分析仪上的离子交换色谱法分离并测量游离氨基酸。为每个实验室提供了详细方法以及装有标准溶液的密封小瓶。对于以半胱磺酸形式测定半胱氨酸，6种成分的重复样品在各实验室之间的变异系数范围为7.13%至10.8%。对于以甲硫氨酸砜形式测定蛋氨酸，6种成分的重复样品在各实验室之间的变异系数范围为1.18%至12.8%。半胱氨酸和蛋氨酸的回收率通过对β-乳球蛋白的分析来确定，并基于氨基酸序列数据中每种氨基酸的预期水平。半胱氨酸的平均回收率为95%，范围为91%至101%。蛋氨酸的平均回收率为101%，范围为98%至106%。此方法已被采用为官方首次行动方法。