Optimization of the antioxiant peptides production from goat milk casein hydrolyzed by alcalase and papain using respons surface methodology

Abstract

Antioxidant peptides are widely used in many fields due to their biological activities
such as anti-cancer, anti-induction and anti-aging. However, little information is
available concerning the peptides production by enzymatic hydrolysis of casein from
goat milk. In this study, response surface methodology (RSM) was applied to optimize
the conditions of the hydrolysis of goat milk casein by proteases (alcalase in
combination with papain) to increase the antioxidant activity of the peptides. The
results showed that the optimal hydrolysis conditions were as follows: temperature of
61°C, enzyme/substrate ratio (E/S) of 5.6%, and protease ratio (papain: alcalase) of
1.8:1. Under the optimal conditions, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical
scavenging activity significantly increased (1.17 folds compared to un-optimized
conditions). Furthermore, Fe2+ chelating ability and superoxide radical scavenging
activity increased 1.02 folds and 1.14 folds, respectively. The antioxidant activity was
significantly improved after optimization and provided a basis for the study of the
antioxidant effects of hydrolysed goat milk casein.