Purification and identification of xanthine oxidase inhibitory peptides from enzymatic hydrolysate of α-lactalbumin and bovine colostrum casein.

The development of food-derived Xanthine Oxidase (XO) inhibitors is critical to the treatment of hyperuricemia and oxidative stress-related disease. Few studies report on milk protein hydrolysates' XO inhibitory activity, with the mechanism of their interaction remaining elusive. Here, different commercial enzymes were used to hydrolyze α-lactalbumin and bovine colostrum casein. The two proteins hydrolyzed by alkaline protease exhibited the most potent XO inhibitory activity (bovine casein: IC50 = 0.13 mg mL-1; α-lactalbumin: IC50 = 0.28 mg mL-1). Eight potential XO inhibitory peptides including VYPFPGPI, GPVRGPFPIIV, VYPFPGPIPN, VYPFPGPIHN, QLKRFSFRSFIWR, LVYPFPGPIHN, AVFPSIVGR, and GFININSLR (IC50 of 4.67-8.02 mM) were purified and identified from alkaline protease hydrolysates by using gel filtration, LC-MS/MS and PeptideRanker. The most important role of inhibiting activity of peptides is linked to hydrophobic interactions and hydrogen bonding based on the results of molecular docking and molecular dynamics simulation. The enzymatic hydrolysate of α-lactalbumin and bovine colostrum casein could be a competitive candidates for hyperuricemia-resisting functional food.

Low-fat ice cream model system: impact of incorporation of alcalase hydrolyzed zein.

Research on fat substitutes with low calories and good flavor is important to reduce the fat content in food. In this paper, the selection of fat substitutes and the preparation of low-fat ice cream were carried out through looking at the emulsion properties of the enzymatic hydrolysis of zein. The results showed that the emulsifying activity of zein after enzymatic hydrolysis for 10 min was 66.76 m2 g-1, and the emulsifying stability was 78.51 min, showing the best emulsifying properties. Enzymatic hydrolysis of zein can effectively reduce the degree of lipid oxidation. The protein digestibility in intestinal juice was also significantly improved, and the release rate of free fatty acids in the emulsion reached more than 80%. The viscosity, shear stress, elastic modulus, electronic nose and electronic tongue of ice cream with 10% oil substitute were close to those of full-fat ice cream. It is expected to provide a basis for the development of functional foods.