Antioxidant activity, functional properties and bioaccessibility of whey protein hydrolysates

The main objective of this study was to produce the functionally improved whey protein hydrolysate with high bioaccessible antioxidant activity. The hydrolysate with highest antioxidant activity, mainly composed of hydrophilic antioxidant peptides and suitable for preventing oxidation in polar food matrices, was produced by tryptic hydrolysis conducted at 37 degrees C and an enzyme/substrate (E/S) ratio of 0.5%. The hydrolysate exerted significantly improved antioxidant activity (80.0%), digestibility (95.9%) and bioaccessibility (124.6%) compared to the native whey proteins (32.1%, 87.1% and 106.3%, respectively) as widely used food supplement. The high bioaccessibility indicates the preservation of hydrolysate bioactivity during the process of gastrointestinal digestion, as a particular challenge in its application.