Abstract:

Egg white proteins and soybean proteins were hydrolyzed by alcalase and/or pepsin, and the hydrolysate Ⅰ(A-P) H
from egg white proteins and Ⅱ PH from soybean proteins with higher antioxidant activities were obtained. Ultrafiltration and
resin separation of these two hydrolysates were carried out, respectively, and the fraction ⅠFs from Ⅰ(A-P)H and ⅡFs from
ⅡPH with stronger activities were obtained. The hydrolysates Ⅰ(A-P)H and ⅡPH as well as the fractions ⅠFs and ⅡFs were
combined, and the synergistic antioxidant effect of the mixtures was analyzed through three antioxidant evaluation systems
including total reduce power, DPPH radical and hydroxyl radical scavenging activities as well as Chou-Talalay combination
index (CI). The results showed that CIreducing power, CIDPPH radical and CI·OH values of the mixture of Ⅰ(A-P)H and ⅡPH were
0.404, 0.827 and 0.557, respectively. Moreover, CIreducing power, CIDPPH radical and CI·OH values of the mixture of fractions ⅠFs and
ⅡFs were 0.344, 0.383 and 0.808, respectively. Compared with the combined enzymatic hydrolysates, the CIreducing power and
CIDPPH radical of the mixture of their fractions were reduced by 14.85% and 53.69%, respectively. The results demonstrated
that the hydrolysates Ⅰ(A-P)H and ⅡPH as well as the fractions ⅠFs and ⅡFs possess remarkable synergistic antioxidant
effects, and ultrafiltration and resin separation can effectively enhance antioxidant abilities of the hydrolysates and their
synergistic effects.

Key words: egg white protein, soybean protein, synergistic effect, antioxidant activity