Recovery of a Protein Hydrolysate from Baby Clam (<i>Corbiculidae</i> sp.) Meat with Angiotensin I-Converting Enzyme Inhibition Activity and Functionalities

The aim of this study is to investigate the angiotensin I-converting enzyme (ACE) inhibition activity and evaluate the technological functionalities of baby clam (Corbiculidae sp.) meat protein hydrolysate. Utilizing Alcalase hydrolysis under a specific condition, the clam meat protein hydrolysate had a degree of hydrolysis (DH) of 42.32 ± 0.15% and demonstrated an ACE inhibition activity of 85.99 ± 2.83%. Remarkably, the hydrolysate maintained over 59% of its initial bioactivity after exposure to pH from 1 to 11 or after heat treatment (100 °C, 180 min). It exhibited excellent solubility, ranging from 78.05 to 96.39% within the pH range of 3–8, even after heat treatment (63 °C, 30 min or 93 °C, 30 s). Within this pH range, the hydrolysate showed the highest foaming capacity (FC) of 53.83 ± 2.02% and a foaming stability (FS) of 34.67 ± 3.01%. Its emulsifying activity index (EAI) peaked at 148.35 ± 2.36 m2/g at pH 3, while the emulsifying stability index (ESI) reached its maximum of 118.60 ± 2.44 min at pH 6. The hydrolysate’s water-holding capacity (WHC) was 2.10 ± 0.10 mL water/g hydrolysate powder. Besides, the oil-holding capacity (OHC) was 5.20 ± 0.20 mL oil/g hydrolysate powder. Notably, the <1 kDa peptide fraction exhibited the strongest ACE inhibition activity, with a half inhibition concentration (IC50) of 0.093 mg/mL, 593.76 times higher than that of lisinopril. These results indicate that the clam meat hydrolysate has potential as a bioactive food supplement with multiple functional properties.