Preparation and assessment of ACE-inhibitory hydrolysates derived from muskmelon ( Cucumis melo ) seed protein utilising crude and activated charcoal-purified enzyme from Wrightia tinctoria

This study evaluates the potential of charcoal-purified Wrightia tinctoria protease for generation of sheep lung ACE-inhibitory peptides from muskmelon seed protein. Purification was optimised by adjusting enzyme protein-to-charcoal ratio, pH, incubation time, and centrifugation speed. Protein was hydrolysed using crude and purified enzymes. 16% Tricine-SDS PAGE was used to validate hydrolysis. Partial purification achieved a purification fold of 1.39 ± 0.03 with 103.09 ± 2.12% recovery at an enzyme-charcoal ratio of 1:0.25 (w/w), pH 7, 30 min, and 4000 rpm (p < 0.05). This enhanced hydrolysis of muskmelon protein to 45.51 ± 2.8% compared to crude enzyme (39.48 ± 1.02%). PAGE revealed disappearance of high-molecular-weight proteins (97.4–3.5 kDa) after acid precipitation, leaving peptides of 14.3–3.5 kDa. Hydrolysate exhibited ACE inhibition of 70.39 ± 3.33%, higher than that of crude-enzyme hydrolysate 52.86 ± 3.17 (p < 0.01). Partial purification significantly improved plant protease’s efficiency in producing low-molecular-weight ACE-inhibitory peptides.