富硒大豆中蛋白提取工艺优化及HPLC-MS联用测定硒代蛋氨酸

根据Box-Behnken试验设计原理和响应面分析法确定了富硒大豆中硒蛋白提取的最佳工艺；在此条件下，获取可溶性硒蛋白中的硒代氨基酸，并采用高效液相色谱-质谱联用技术对富硒大豆可溶性蛋白中的硒代蛋氨酸进行定性定量分析。结果表明，液料比11∶1（mL/g）、提取温度 44 ℃、提取时间96 min时，可溶性硒蛋白的提取率可达到76.03%。对4 种自行种植的富硒大豆中可溶性蛋白分析可知：硒-L-蛋氨酸中硒含量与可溶性蛋白中硒含量、富硒大豆中总硒量呈正相关；实验范围内硒代蛋氨酸相对于可溶性蛋白中硒含量最高可达28.46%；说明富硒大豆中不仅含有硒代蛋氨酸，还存在其他形态的硒代氨基酸，有待于进一步研究探索。对大豆进行富硒种植，不仅能提高大豆中含硒总量，而且能通过大豆的生物代谢将其转化成安全无毒营养的有机硒。

Optimization of Protein Extraction from Selenium-Enriched Soybean and Determination of Selenomethionine by Liquid Chromatography Coupled with Mass Spectrometry

Based on single factor experiments, the extraction process for selenium-enriched soybean protein was optimized
through Box-Behnken central composite design and response surface methodology. Selenoamino acids were obtained from soluble
protein under the optimized extraction conditions. Selenomethionine was qualitatively and quantitatively analyzed by liquid
chromatography coupled with mass spectrometry. The optimal conditions for extraction were determined as the follows: liquid/
material ratio, 11:1; extraction temperature, 44 ℃; and extraction time, 96 min. The yield of soluble selenium-containing protein
under these conditions was 76.03%. Analysis of soluble proteins from four soybeans enriched with four different levels of selenium
indicated that the content of selenium in selenomethionine accounted for 28.46% of the total selenium. Thus, other selenoamino
acids also existed besides selenomethionine. Soybeans were able to not only absorb and accumulate selenium, but also to transform
inorganic selenium into organic selenium compounds with higher bioavailability and less toxicity. This study provides a scientific
approach for developing selenium-enriched functional organic food based on soybeans.