紫阳富硒茶中硒的赋存形态及浸出率研究

摘要

研究紫阳富硒茶中硒的赋存形态及其浸出率。采用盐酸浸提法提取硒蛋白，硒多糖用[（1∶1酚-二氯甲烷）-异戊醇]（24∶1，mL/mL）法除去蛋白质后进行提取，同法提取硒核酸，去除蛋白质后，酸法提取。采用氢化物发生原子荧光法测定茶叶总硒含量及与蛋白质、多糖、核酸结合的硒含量。结果表明：硒蛋白、硒多糖分别占样品总硒的51.65%和25.23%；浸泡温度，浸泡时间和浸泡次数是影响硒浸出率的主要因素，冲泡水温为95℃时硒浸出率高达46.35%；浸泡3 min时，硒的浸出率为25.80%，达最大值。浸泡次数为3次时，茶汤中硒的含量极微。富硒茶中的硒绝大部分是对人体有益的有机硒，硒蛋白>硒多糖>硒核酸；饮茶时应选择水温95℃下浸泡茶叶，且浸泡3 min，浸泡2次为佳。%The extraction of selenium and combined of selenium in selenium-riched tea were studied. Protein combined of selenium was extracted by hydrochloric acid, polysaccharide combined of selenium and nucleic combined of selenium were extracted by removing protein combined selenium with [(1∶1 phenol-methylene chloride)-isoamyl alcohol](24∶1,mL/mL). The selenium content of tea and nucleic, polysaccharide and pro-tein combined of selenium were determined by atomic fluorescence spectrometry. The results showed that:Se-protein and Se-polysaccharide accounted for about 51.65%and 25.23%of the total selenium, the most impor-tant factors influencing the dissolution rate of selenium from tea was the soaking temperature, the dunking time and frequency. The dissolution rate was 46.35%at 95℃, and soaking three minutes, the dissolution rate of selenium was 25.80%. Content of selenium could not be detected when dunked three times. The selenium ex-tracted from tea is almost organic selenium, selenium-protein>selenium-polysaccharide>selenium-nucleic. Socking tea should be three minutes and no more than two times at 95℃.