Optimization of the extraction process of ACE inhibitory peptides from distillery waste and their antioxidant activity

ObjectiveThis study aimed to handle distillery waste effectively, research and develop high-value components within distillery waste, and explore its potential application approaches.MethodsProteins were extracted from distillery waste throuth the ultrasonic-assisted alkali extraction and acid precipitation method. Angiotensin-converting enzyme (ACE) inhibitory peptides were prepared by enzymatic hydrolysis of the crude protein of distillery waste using a compound enzyme. The extraction process conditions of ACE inhibitory peptides were optimized by single factor experiments and response surface experiments, and their antioxidant activity was investigated.ResultsThe optimal conditions for preparing ACE-inhibitory peptided by compound enzymatic hydrolysis were as follows: the ratio of enzyme (Vpapainase∶Vneutral protease) was 3∶1, and the hydrolysis was contacted at 55.41 ℃ and pH 7.72, for 2.38 h. Under the control of these conditions, the hydrolysis degree of ACE-inhibitory peptide was 66.62%; the highest ACE inhibitory activity (79.05%) was obtained after 3 h of enzymatic hydrolysis. The scavenging rates of the purified and extracted ACE inhibitory peptides against DPPH and ABTS free radicals were 2.078% and 3.226%, respectively, and the total antioxidant capacities were 1.161 μmol/mL and 1.255 mmol.ConclusionThe process of extracting ACE inhibitory peptide from distillery waste using the compound enzymatic hydrolysis method is feasible.