Optimization of the process of enzymatic hydrolysis of keratin-containing stock aimed at obtaining hydrolysates of high biological value has been performed. The increasing of the stock/water weight ratio, the amount of the alkaline protease preparation from Acremonium chrysogenium added and the temperature of the reaction mixture resulted in an increase in the yield and antioxidant capacity of hydrolysis products. The molecular masses of soluble products obtained under optimal hydrolysis conditions ranged from 3.55 to 3.60 kDa. High antioxidant capacity, 100% bioavailability and a well-balanced amino acid composition was characteristic of the hydrolysis products.