FOOD SCIENCE ›› 2018, Vol. 39 ›› Issue (4): 225-232.doi: 10.7506/spkx1002-6630-201804034

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Speciation Analysis and Bioavailability Assessment of Selenium in Two Selenium-Enriched Foods by in Vitro Biomimetic Gastrointestinal Tract Models

CHEN Shanglong1,2, LIU Enqi1,2, CHEN Anhui1,2, LIU Hui1,2, WU Yonghua1,2, QIN Xu1   

  1. (1. College of Food (Biological) Engineering, Xuzhou University of Technology, Xuzhou 221018, China; 2. Jiangsu Key Construction Laboratory of Food Resources Development and Quality Safe, Xuzhou University of Technology, Xuzhou 221018, China)
  • Online:2018-02-25 Published:2018-02-02

Abstract: 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)2 and 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.

Key words: in vitro biomimetic gastrointestinal tract models, selenium-enriched, speciation analysis, bioavailability assessment, high resolution-continuum source graphite furnace atomic absorption spectrophotometry (HR-CS GFAAS)

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