Enzymatic Hydrolysis of fish waste, characterization of Hydrolysate and Proximate analysis

Abstract

The fish industry generates a lot of waste which is attributable to the fact that there is an increased demand for fish and that filleting of tilapia fish yields about 37% skin-off fillets. Enzymatic hydrolysis used in this research project affords the prospect to apply rudimentary alkaline protease obtained from extremophile bacteria in processing fish waste. The optimum working conditions of the crude alkaline protease were established to be at 80⁰C, pH12 and a crude enzyme concentration of 100%. The Amino acid composition was determined using HPLC while fatty acid analysis using the FAME method using GC equipped with the FID. Proximate analysis was determined in accordance with the standard test methods. The parameters evaluated included moisture, crude protein, ash, carbohydrates and fats. The kinetics of the reaction showed that it was zero order with respect to the concentration of the reactants. Glycine and alanine were determined to be the peak amino acids present in the Fish Protein Hydrolysate, while histidine was the least abundant. Fatty acid composition study disclosed that palmitic acid was most prominent and the least abundant was lauric acid. Proximate analysis of the freeze-dried hydrolysate yielded crude 6 protein, moisture, ash, crude fat, fibre and carbohydrates mean content of 54.2%,10.4 %, 21.8 %, 12.8 %, 0.6 % and 0.2 % respectively. The results demonstrate that the crude enzyme used in this study can be used for fish waste hydrolysis to obtain useful value-added products and can be used effectively in managing the fish waste disposal problem.