The effects of mulberry polyphenols on the digestibility and absorption properties of pork myofibrillar protein in vitro

The objective of the present study was to explore the effect of mulberry polyphenols on the digestibility and absorption properties of myofibrillar protein (MP) in vitro. MP was extracted from the Longissimus et thoracis muscle of 18 different pig carcasses and the MP-mulberry polyphenols complex was prepared. The antioxidant activity of digestive juice, degradation of both MP and polyphenols, and the metabolism of MP and the MP-polyphenols complex by intestinal microbial activity during digestion and fermentation in vitro were compared. The results showed that mulberry polyphenols significantly affect the digestibility of MP and the antioxidant activity of digestive juices during digestion (P < 0.05). After the modification of the polyphenols, the hydrolysis of MP increased from 55.4% to 64.0%, and the molecular weight of protein digestion product significantly decreased (P < 0.05). The scavenging rates of 2, 2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl in the final digestive juice were 350.1 μmol Trolox/mg protein and 34.0%, respectively, which were 0.34 and 0.47-fold higher than those of the control (P < 0.05). Furthermore, the release and degradation of phenolic compounds mainly occurred during intestinal digestion, and polyphenols that reached the colon after digestion, through the fermentation of intestinal microorganisms in vitro, enriched Lactobacillus and promoted the production of short-chain fatty acids which has obvious potential to improve intestinal health.