Abstract: This study was designed to optimize the enzymatic preparation of hypoglycemic peptides from red deer (Cervus elaphus) antlers. Alcalase, flavourzyme, neutral protease and trypsin were comparatively evaluated based on α-glucosidase inhibitory activity of hydrolysates to select two suitable enzymes for sequential hydrolysis of red deer antlers. The sequences of two hydrolysis steps were compared for better hypoglycemic activity in vitro and the hydrolysis conditions were optimized based on degree of hydrolysis (DH), α-glucosidase inhibitory activity and protein recovery with one-factor-at-atime method and orthogonal array design. The results showed that alcalase and flavourzyme were found to be more suitable and sequential use of alcalase followed by flavourzyme was optimal for higher percentage inhibition of α-glucosidase activity, DH and protein recovery, reaching 21.11%, 19.88% and 39.12%, respectively. The optimal hydrolysis conditions were obtained as follows. Red deer antlers were hydrolyzed firstly with 5 000 U/g alcalase at an initial pH of 8.0 and 60 ℃ with a substrate concentration of 12% for 3 h, and then with 6 000 U/g flavourzyme for 1 h at 45 ℃ with a substrate concentration of 5% after pH adjustment to 6.5. The final hydrolysate exhibited concentration-dependent α-glucosidase inhibitory activity, with a percentage inhibition of 94.09% at 3 mg/mL and IC50 value of 1.82 mg/mL. It was concluded that alcalase-flavourzyme hydrolysis would provide an efficient way to prepare hypoglycemic peptides from red deer antlers.

Key words: Cervus elaphus antler, enzymatic hydrolysis, hypoglycemic peptide