A novel antioxidative peptide derived from chicken blood corpuscle hydrolysate.

Chicken blood contains copious amounts of edible protein, which is currently underutilized. In this study, chicken blood corpuscle was hydrolyzed using two proteases (papain and flavourzyme) and its hydrolysis conditions were optimized by means of response surface methodology (RSM). The optimal conditions based on obtaining a hydrolysate with maximum antioxidant activity were E/S 2.0%, temperature 50°C, and time 6.0h. Under the above conditions, the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, superoxide anion scavenging activity and reducing power of papain and flavourzyme hydrolysate (PFH) were 94.99±0.31%, 57.39±2.82%, and 1.83±0.06, respectively. Additionally, PFH showed not only a stable DPPH scavenging activity in the pH ranges of 1 to 7, but also a good tolerance to magnesium (Mg2+), potassium (K+) and calcium (Ca2+). We also found that PFH retained at least 95% of antioxidant capacity under simulated gastrointestinal digestion. Subsequently, PFH was purified sequentially by ultrafiltration, anion exchange chromatography, gel filtration chromatography, and high-performance liquid chromatography (HPLC). Finally, the sequence of the peptide with the highest antioxidant activity was identified to be AEDKKLIQ (943.5Da) using LC-ESI-MS/MS. Further, this peptide showed free radicals scavenging ability and reducing power as well as that of GSH (P>0.05), further evidencing its potential used as an antioxidative ingredient.