Abstract:

Protein hydrolysates were prepared by enzymatic hydrolysis of duck meat for different times with protamex,
flavourzyme, trypsin and sequential hydrolysis using trypsin followed by protamex or flavourzyme, respectively, and
investigated for antioxidant activities as a function of hydrolysis time and protease type. The antioxidant activities were
evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and superoxide anion radical scavenging capabilities as well
as reducing power. The results showed that the DPPH radical scavenging activity of each hydrolysate was positively dependent
on hydrolysis time, while the hydroxyl and superoxide anion radical scavenging activities and reducing power first increased
and then decreased (P < 0.05). The protamex hydrolysate exhibited the strongest radical scavenging activities, which could
scavenge (75.70 ± 1.54)% of DPPH radical, (59.41 ± 1.24)% of hydroxyl radical and (98.50 ± 4.51)% of superoxide anion
radical, while the hydrolysate prepared with trypsin plus flavourzyme displayed the highest reducing power (0.330 ± 0.017).
Therefore, the antioxidant activities of duck meat hydrolysates were determined by the hydrolysis time and protease types.
Protamex was the best candidate for preparation of antioxidant peptides derived from duck meat.

Key words: duck meat, hydrolysis time, protease, antioxidant activity