Abstract:

In order to achieve an in-depth development of konjac fly powder, the technology for preparation of angiotensin- I-converting enzyme (ACE) inhibitory peptides by hydrolyzing this resource was studied. The optimum protease and the optimum hydrolysis conditions were determined for maximizing ACE inhibitory activity in vitro of konjac fly powder hydrolysate. Results showed that alkaline protease was the optimum protease to hydrolyze konjac fly powder protein. The optimum conditions for alkaline protease-catalyzed enzymolysis were as follows: substrate concentration 2.25%, temperature 50 ℃, enzyme concentration 3500 U/(g substrate), and pH 8.0 for a hydrolysis duration of 270 min. Under the optimum conditions, the ACE inhibitory ratio of konjac peptides with a yield of 12.70% was 95.69%. After freeze drying, konjac peptides powder with yellowy color and an IC50 of 0.80 mg/mL was obtained, which comprised 52.67% peptides and 62.30% protein. In conclusion, the developed enzymolysis technology is feasible for the preparation of ACE inhibitory peptides with high biological activity from konjac fly powder.

Key words: konjac fly powder, hydrolysis, ACE inhibitory ratio, yield