Utilization of Low-Value Fish Biomass and Processing By-Products through Papain Hydrolysis: Production and Proximate Composition of a Fish Protein Hydrolysates

This research investigates the production of fish protein hydrolysate (FPH) from marine small and medium-sized low value fishes using meat, skin, and viscera as raw materials. Enzymatic hydrolysis was employed as an effective method to convert underutilized fish resources into a value-added protein product. All experiments were performed in triplicate, and results are presented as mean ± SD. An overall yield of 8% FPH was obtained from 100 g of minced raw material. The hydrolysis conditions were selected based on preliminary experiments aimed at maximizing degree of hydrolysis and yield and were conducted at 40 °C and pH 6.7 with a 1% enzyme-to-substrate ratio for 120 minutes, resulting in an 18.09% degree of hydrolysis and 8.02% yield. Proximate composition analysis of the FPH (dry-weight) indicated a high crude protein content of 81.93%, along with low levels of crude fat (1.9%), ash (6.6%), and moisture (8.9%). In comparison, the raw fish (wet-weight) exhibited crude protein of 13.47%, crude fat 5.24%, ash 2.29%, and moisture 78.68%. The results highlight a substantial enhancement in protein concentration and a marked reduction in fat and moisture following hydrolysis. The findings suggest that marine low value fish can be effectively utilized for the production of protein rich ingredient fish protein hydrolysate, offering promising potential for applications in food, feed, and nutraceutical industries.