Optimization and quality determination of protein hydrolysate oil obtained by using rainbow trout (Oncorhynchus mykiss) by-products via response surface method

With the population increasing every year in the world, the trend towards new foodstuffs and their production is also becoming an important issue. Aquaculture byproducts are high potential recycling resources rather than pollution. The evaluation of these by-products is very important in terms of producing high value-added products for the country's economy and preventing environmental pollution. Since fish oil is the main source of ω-3 PUFAs, this resulting lipid has promising potential for human and animal consumption. Within the food chain, the large amount of waste produced by the rainbow trout (Oncorhynchus mykiss) fishing industry represents a rich pool of bioactive molecules, including polyunsaturated fatty acids, vitamins, amino acids (AA), and peptides. In this study, the most appropriate time, temperature, and enzyme rate were determined in the optimum hydrolysis process of trout (Oncorhynchus mykiss) waste using commercial enzymes. The yield of the oil produced during this process varied between (5.75-11.46%) and the best result was obtained because of enzymatic hydrolysis at 40 °C. In terms of lipid quality, PV values were found between (1.78-3.47 meq O2/kg), as the hydrolysis time increased, an increase was observed in PV values, TBA values were found between (0.41-1.41 MDA/kg) and the increase in hydrolysis temperature caused an increase in TBA. FFA was found between (0.27-4.12%). Its fatty acid composition, quality and balance were examined for suitability for human and animal consumption. SFA (22.5%), MUFA (46.31%), PUFA (23.52%) were found. Fish oils recovered from fish by-products have been shown to contain high levels of PUFA, especially EPA and DHA.