Preparation and stability of angiotensin-I-converting enzyme (ACE) inhibitory peptides from protein hydrolysate of Wuyi rock tea residues

Wuyi rock tea residues, generated after brewing or aroma extraction, are rich in nutrients. This study aimed to prepare ACE inhibitory peptides from the protein hydrolysate of Wuyi rock tea residues and investigate their stability. The optimal proteolysis conditions for neutral protease were optimized as: a substrate concentration of 2% (w/v), pH 7.0, hydrolysis temperature of 45°C, enzymatic digestion time of 3 h, and enzyme dosage of 6800 U/g. Under these conditions, the ACE inhibition rate of protein hydrolysate of Wuyi rock tea residues reached 70.47 ± 0.29% at a concentration of 0.5 mg/mL. Additionally, the prepared ACE inhibitory peptides demonstrated excellent stability against acid, base, heat, and certain metal ions. These findings suggest that the proteins extracted from Wuyi rock tea residues can serve as a promising source to produce highly active ACE inhibitory peptides. These peptides could be utilized in the development of nutraceuticals, functional foods, and pharmaceuticals.