Abstract:

This research was designed to prepare antioxidant peptides derived from goat brain protein. The protein
content and amino acids composition of defatted goat brain were determined. The molecular mass distribution of protein
hydrolysates by neutral protease from Bacillus subtilis at different times was analyzed by sodium dodecyl sulfatepolyacrylamide
gel electrophoresis (SDS-PAGE), and goat brain protein hydrolysates were separated and purified by
Sephadex G-25 gel filtration chromatography and Sephadex G-15 gel filtration chromatography. The antioxidant activity of
the resulting fractions was evaluated by DPPH, hydroxyl radical, superoxide anion radical, and nitrite radical scavenging
assays. The results showed that the protein content of defatted goat brain was 60.55% and contained seven essential amino acids
among which glutamic acid and aspartic acid were the most predominant. The molecular mass of the hydrolysates was below
10 kD. After purification by Sephadex G-25 gel filtration chromatography, the six fractions of the hydrolysates were obtained and
F4 fraction showed the strongest antioxidant activity. F4 was further purified into three fractions by Sephadex G-15 gel filtration
chromatography, including F4-2 showing the strongest antioxidant activity. The IC50 values of F4-2 for scavenging DPPH,
hydroxyl radical, superoxide anion radical, and nitrite radicals were 1.64, 2.47, 7.98 and 5.14 mg/mL respectively.

Key words: goat brain protein, peptides, separation and purification, antioxidant activity