Enzymatic Processing of Grouper Bone Waste as Fish Protein Hydrolysate Potential Bioactive Peptides

Grouper fish is a type of reef fish that has high economic value and is widely used as fillets in the industry. It is estimated that 50% of the total fish catch is not used as food. Fish solid waste has been utilized as a source of protein and essential amino acids with high nutritional value over the last decade. Enzymatic hydrolysis is the most recommended method to produce fish protein hydrolysates. Enzymatic hydrolysis with various enzymes and hydrolysis time can determine the characteristics of the hydrolysate obtained. The results of hydrolysis of fish bone powder using variations of Papain, Bromelain, and alcalase enzymes, along with time variations of 30-300 minutes, showed the highest yield with papain enzymes at a hydrolysis time of 240 minutes. The degree of hydrolysis above 88% was achieved at an incubation time of 120 minutes with papain enzyme and alkalase and 3 hours with bromelain enzyme. The proximate content of protein hydrolysates from fish bones showed a moisture content of between 7% and 15%, an ash content below 0.5%, and a protein content of 0.46%. The results of protein hydrolysis molecular weight analysis using SDS-PAGE revealed that each enzyme yielded peptides at sizes of 5 and 3.4 kDa, which are expected to have potential as bioactive peptides.