Effects of selenomethionine on the in vitro digestibility of myofibrillar protein of pearl gentian grouper

In this study, the effects of selenomethionine on the in vitro digestibility of myofibrillar protein (MP) of pearl gentian grouper were studied by using a static in vitro digestion model to simulate gastric and intestinal digestion. The results showed as follows: after simulated gastric and intestinal digestion, the selenium content of high-level selenomethionine group (Y2 group) (0.130 mg/kg, 0.072 mg/kg) was significantly higher than that of control group (C group) and low-level selenomethionine group (Y1 group) (P < 0.05). However, the carbonyl content (2.02 nmol/mg, 2.59 nmol/mg), dityrosine content (3962 a. u. , 4062 a. u.), thiobarbituric acid (TBA) value (0.31 mg/kg, 0.32 mg/kg), and particle size (365 nm, 357 nm) of Y2 group were significantly lower than those in C group and Y1 group (P < 0.05). Besides, the UV absorption peaks and endogenous fluorescence intensities of the Y2 group were higher. The results showed that high-level selenomethionine delayed MP′s oxidation and denaturation process,and better maintained the structure of MP during digestion. The in vitro digestibility (62.19%, 67.25%) and the degree of hydrolysis (0.31 mmol/g, 0.34 mmol/g)of the Y1 group were significantly higher than those of the C group and Y2 group (P < 0.05). In conclusion, the supplementation of selenomethionine not only improves the antioxidant capacity of MP but also improves its in vitro digestibility, indicating that selenomethionine has potential application in improving the nutritional quality and stability of fish protein.