Analysis of chemical compositions and functional component of polysaccharide-protein conjugates in black soybean and sprouts

• Main Authors: MA, YUNG-SHUN, 馬詠舜
• Other Authors: LU, CHUN-PING
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/z59c7r

碩士 === 輔仁大學 === 食品科學系碩士班 === 106 === Previous studies have shown that the antioxidant activities of Tainan No. 3 black soybean polysaccharide (BSPS) were best after seed germination on the fifth and seventh days. The high performance liquid chromatography (HPLC) analysis of BSPS also showed the molecular weight of the F1 fraction degraded with germination time. To clarify the relationship between constituents and antioxidant activities, the chemical composition and structural characteristics of BSPS and F1 in black soybean seeds and sprouts were studied. The BSPS and F1 fraction were isolated from seeds and sprouts respectively, and their protein and phytochemical contents were evaluated. Data showed the protein content decreased during germination and the O-linked glycosylation was demonstrated between carbohydrate and protein after alkaline β-elimination treatment of BSPS and F1. The analysis of glycosidic linkages showed that 1, 6 glycosidic linkage of glucose and 1, 6 glycosidic linkage of galactose were abundant in BSPS. The acidic functional group of F1 was identified by fourier transform infrared spectroscopy (FTIR) analysis in accordance with our previous research showing galacturonic acid was found in F1 polysaccharides. Phytochemical analysis showed that the F1 contained phenolics and flavonoids. The total phenolic content (TPC), the total flavonoid content (TFC), and aglycone forms of isoflavones, including daidzein, glycitein and genistein all increased during germination, but antioxidant activities of reducing power and the Trolox equivalent antioxidant capacity (TEAC) reduced after removing protein moieties of F1. In summary, water-soluble polysaccharides of black soybean seeds and sprouts are polysaccharide-protein conjugates and non-covalently interacted with phytochemicals. Therefore, three components, carbohydrate, protein and phytochemicals in polysaccharides all contribute to the antioxidant capacity. The greatest amounts of phenolic compounds and isoflavones were found on the seventh day of sprouting and have potential to develop functional foods in the future.