Potential Anti-Sarcopenia Effect and Physicochemical and Functional Properties of Rice Protein Hydrolysate Prepared through High-Pressure Processing

Rice protein is a suitable alternative protein source for dairy protein in infant formulas on account of its unique nutrition and hypoallergenicity. Rice protein was isolated through enzymatic hydrolysis (Alcalase, papain, bromelain, Flavourzyme((R))) in combination with high-pressure processing (HPP) (400 MPa for 15 min at 25 degrees C) to enhance its functional properties and broaden its food processing applications. The effect of the HPP-treated rice protein hydrolysate on dexamethasone (DEX)-induced atrophy in C2C12 myotubes was also studied. The length of myotubes was observed under a light microscope, and periodic acid Schiff staining. The results showed that even though enzymatic hydrolysis and HPP treatment affected the color of the resulting rice protein, the protein content (3120.31 +/- 42.15), branched chain amino acid (BCAA) content (15.12 +/- 1.03), peptide content (31.25 +/- 0.55), and amino acid composition of the rice protein were significantly increased. Moreover, the combined enzymatic and HPP treatment effectively overcame the problem of limited solubility and water-holding capacity. Rice protein produced through enzymatic and HPP treatment exhibited a higher free radical scavenging activity and oxygen radical absorbance capacity. It also alleviated DEX-induced muscle atrophy in C2C12 myotubes as indicated by the increase in myotube length. In short, the enzymatic and HPP treatment of rice protein not only overcame limitations, but also produced rice protein with high functionality in terms of antioxidant and therapeutic effects on muscle atrophy. The rice protein hydrolysate produced through enzymatic hydrolysis and HPP treatment showed the potential for use as an ingredient for functional foods in the nutraceutical industry.