Antioxidant Activity Of The Hydrolysates Of Cheese Whey

Whey is the by-product of cheese industry. With its great nutritious components, especially whey proteins, whey is one of the most significant materials in producing of bioactive peptides. Hydrolysis of whey proteins and fermentation with lactobacillus are new methods for making antioxidative peptides. It is valuable to study on the development and application of anti-oxidative peptides derived from milk proteins.Cheese whey came from our laboratory. The optimum hydrolysis condition of Alcalase was studied, and technological condition was optimized with orthogonal experiment. The optimized hydrolysis parameters included:pH9.0, temperature50℃,[E/S]4%. After2hour operation, the degree of hydrolysis of the peptides solution was25.42%. And the antioxidant activity in a liposome system with thiobarbituric acid-reactive substances (TBARS) as the indicator, reducing power, superoxide and hydroxyl free radical scavenging activity of the various hydrolysates were evaluated. In addition, the antioxidative activity was studied for of Lactobacillus helveticus fermented whey.Ultrafiltration and Sephadex G-50were used to separate the bioactive fictions with great anti-oxidative property. The results showed that the anti-oxidative activity of hydrolysate of Alaclase2.4L was improved after ultrafiltration. Moreover, peptides of4000-6000Da contributed mostly to the anti-oxidative property of cheese whey. In addition, the quantity of the antioxidants was increased after ultrafiltration, measured with flux of membrane, the optimized parameters of ultrafiltration included:room temperature, time120min, pressure0.25MPa and pH9.0.Alcalase hydrolysated product was separated by Sephadex G-50, then two purified fractions were gained, and the second one had the higher antioxidative activity, that was40.12%. So the second apex should be collected in the hydrolysate of Alcalase2.4L. Also, hydrolysate of Papain was separated by Sephadex, and four apices were showed. The forth one had the highest antioxidative activity, that was34.79%.The in vitro and in vivo antioxidative activities of hydrolysates of cheese whey were investigated, and great antioxidative activity of them was demonstrated. Hydrolysed whey increased the activities of SOD in serum and liver, and the activities of GSH-Px was increased by hydrolysate of Alaclase2.4L. Hydrolysed whey had no effect on MDA level in the serum and liver of mice.