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Effects of simulated gastrointestinal digestion on the physicochemical properties, erythrocyte haemolysis inhibitory ability and chemical antioxidant activity of mulberry leaf protein and its hydrolysates
Author(s) -
Sun Chongzhen,
Wu Wenjia,
Yin Zhina,
Fan Liuhui,
Ma Yurong,
Lai Furao,
Wu Hui
Publication year - 2018
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.13584
Subject(s) - antioxidant , chemistry , abts , dpph , digestion (alchemy) , hydrolysate , trolox , haemolysis , pepsin , food science , biochemistry , glutathione , hydrolysis , enzyme , chromatography , biology , immunology
Summary Proteins and peptides must be degraded and modified in the gastrointestinal ( GI ) tract prior to absorption; this process changes their physicochemical and biological properties. Mulberry leaf protein ( MP ) and its hydrolysates ( HMP ) have favourable antioxidant activities. To investigate, in vitro and separately, the effects of GI digestion and intestinal digestion on the stability of MP and HMP , we monitored the changes in secondary structures, amino acids, molecular weights and antioxidant activities. We found that MP was more hydrolysed by pepsin than by pancreatin, unlike HMP . The final digests of MP and HMP were mainly composed of polypeptides (0.5–6.5 kDa) and oligopeptides (<0.5 kDa), respectively. The GI digestion influenced MP and HMP differently; GI digestion increased the antioxidant efficiency of MP and decreased that of HMP . For the intestinal digests, the antioxidant activities of MP and HMP also differed. The 1,1‐diphenyl‐2‐picrylhydrazyl ( DPPH ) and 2,2′‐azinobis (3‐ethylbenzothiazoline‐6‐sulphonic acid) diammonium salt ( ABTS ) radical quenching abilities of MP and HMP at 1 mg mL −1 were comparable to or exceeded that of L ‐glutathione ( GSH ) and 6‐hydroxy‐2,5,7,8‐tetramethychroman‐2‐carboxylic acid (trolox). Meanwhile, the erythrocyte haemolysis rates of MP , HMP and their GI products at 0.05–1.0 mg mL −1 were significantly lower than that of the 2,2′‐azobis (isobutyramidine) dihydrochloride ( AAPH ) control. Both MP and HMP can be used as natural antioxidants and may promote digestive health.