The Correlation Between In Vitro Antioxidant Activity and Immunomodulatory Activity of Enzymatic Hydrolysates from Selenium‐Enriched Rice Protein

The antioxidant and immunomodulatory activities of selenium-enriched rice protein hydrolysates (Se-PH) were evaluated by a cellular antioxidant activity test and macrophage proliferation and phagocytosis assays, respectively. The results showed that trypsin hydrolysate provided the highest proliferation rate of 60.91% at a concentration of 100 µg/mL. Moreover, a remarkable rise in the phagocytosis rates for trypsin hydrolysate (64.1%) and pepsin–trypsin hydrolysate (54.5%) was observed when the sample concentrations were increased to 50 µg/mL. A positive correlation was found between the phagocytic ability of macrophages and both the selenium concentration and the degree of hydrolysis of Se-PH, and the correlation coefficients Robtained were 0.792 and 0.930 (P< 0.05), respectively. The capacity of Se-PH to inhibit the oxidation of dichlorodihydrofluorescein had a significant negative correlation with the phagocytic ability of macrophages (R= –0.840, P< 0.05). In conclusion, a positive correlation was found between the antioxidant activity and the immunomodulatory activity of Se-PH, which could be used as potential functional food additives for improving human health. In recent years, Se-enriched rice has been widely studied due to its high value of nutrition and health. However, byproducts of Se-enriched rice such as rice bran or broken rice, which are commonly fed to livestock, have not yet been fully utilized. Therefore, it is of great interest to extract Se-containing proteins and prepare Se-peptides with various biological activities from Se-enriched rice by-products. The results of this study indicate that the antioxidant activity and immune activity of Se-PH, which could be potential functional food additives for human health in the food industry.