QIN Xiuyuan1, LIU Wenying1, ZHANG Jingbo2, ZHU Shaoxin2, LU Jun1, GU Ruizeng1, CAI Muyi1*, ZHANG Chunle2*
1(Beijing Engineering Research Center of Protein and Functional Peptides, China National Research Institute ofFood and Fermentation Industries Co., Ltd, Beijing 100015, China); 2(Guangdong Sino Nutri-food Biological Technology Co., Ltd, Dongguan 523122, China)
Abstract: Selenium-chelating pea oligopeptides were prepared by using pea oligopeptide and sodium selenite as raw materials. The basic physical and chemical properties of selenium-chelating pea oligopeptides including moisture content, acid soluble protein, total nitrogen and molecular weight distribution were analyzed. Taking the molecular weight and selenium content as indicators, the effects of temperature, pH and in vitro simulated gastrointestinal digestion were investigated. The results showed that the moisture content, acid soluble protein content, total nitrogen content and the molecular weight of the product were (14.17±1.12)%, (23.22±0.12)%, (23.87±0.30)%, and below 1 000 Da, respectively. At the temperature of 25-100 ℃, the change of the proportion of molecular weight less than 1 000 Da was under 2%, and the variation of selenium content is not significant. At the pH =3-11, the molecular weight of less than 1 000 Da ratio does not exceed 3%. Although the selenium content has a certain change, it is still above 78%. After digested with pepsin, trypsin and the two enzymes together, the molecular weight was more than 90%, and the selenium content was not significant. This shows that selenium-chelating pea oligopeptide have a certain thermal stability, pH stability and digestion stability.