应用体外全仿生模型初步分析2种富硒产品中硒形态及生物可给性

摘要

建立微波消解-高分辨-连续光源石墨炉原子吸收光谱(high resolution-continuum source graphite furnace atomic absorption spectrophotometry,HR-CS GFAAS)法测定富硒蛹虫草和富硒酵母胃、肠全仿生提取液中各形态硒的方法,研究胃、肠消化对富硒产品中硒形态和生物可给性的影响.采用体外全仿生消化技术对富硒蛹虫草和富硒酵母进行预处理,得到胃、肠全仿生提取液;通过0.45 μm微孔滤膜实现可溶态和悬浮态的分离;选择D101大孔树脂分离可溶态中有机态和无机态;分别利用丙酮和无水乙醇沉淀可溶态中蛋白和多糖,得到蛋白结合态和多糖结合态;分别以正辛醇和单层脂质体为细胞膜,模拟富硒产品中硒在人体胃、肠中的分配行为.通过单因素试验,确定最佳测定条件:分析谱线为196.0267 nm,基体改进剂为1 g/L Pd(NO3)2和0.5 g/L Mg(NO3)2混合溶液,添加体积为5 μL,灰化温度为1100 ℃,原子化温度为2200 ℃.在此条件下,测定富硒蛹虫草和富硒酵母中硒含量分别为2.129 μg/g和27.75 μg/g,肠全仿生提取液中除悬浮态其他各形态硒的含量都高于胃全仿生提取液,在肠消化过程中产生的正辛醇醇溶态硒和单层脂质体结合态硒的含量都高于各自水溶态硒.%An effective method was developed for the speciation analysis of selenium in digests of Se-enriched Cordyceps militaris and selenium-enriched yeast prepared using in vitro biomimetic gastrointestinal tract models by microwave digestion-high resolution-continuum source graphite furnace atomic absorption spectrophotometry (HR-CS GFAAS). The aim was to study the influences of gastric and intestinal digestion on the speciation and bioavailability of Se in selenium-enriched food. The gastric and intestinal digests were separated through a 0.45 μm membrane filter into suspended and soluble Se, and inorganic and organic Se from the soluble fraction were further separated using D101 macroporous resin. Moreover, Se-binding protein and polysaccharide were precipitated by acetone and ethanol, respectively. The partition behaviors of Se from Se-enriched food in the stomach and gut were simulated with n-octyl alcohol and monolayer liposome as cell membrane, respectively. The optimal analysis wavelength for Se was 196.026 7 nm. A mixture of 1 g/L Pd(NO3)2and 0.5 g/L Mg(NO3)2(5 μL) was selected as the best matrix modifier, and an ashing temperature of 1 100 ℃ and an atomization temperature of 2 200 ℃ were used.The results showed that Se contents in selenium-enriched Cordyceps militaris and selenium-enriched yeast were determined to be 2.129 and 27.75 μg/g, respectively under these conditions. The contents of all Se forms except suspended Se in the intestinal digest were higher than in the gastric digest. n-Octyl alcohol-soluble Se and monolayer liposome-bound Se were more abundant than water-soluble Se during simulated intestinal digestion.