Amino acid profile, antioxidant activity, and hybridization levels of gelatine hydrolysates prepared with single or combined enzymes from fish skin and scales

In the present study, gelatin was extracted from the skin and scales obtained from the processing of pangasius fish and sea bass, respectively. Collagen peptides (gelatin hydrolysates) were produced from gelatin using different single enzymes or combinations of enzymes. Samples obtained from fish skin contained 22.81 to 32.80 mg.100 g-1 essential amino acids, whereas those obtained from fish scales had 22.24 to 29.52 mg.100 g-1 essential amino acids. In terms of antioxidant activity, the collagen peptide samples obtained from the skin have DPPH values of 141.00 to 240.21 mg Trolox.100 g-1 and ABTS values of 14.62 to 16.97 mM Trolox.100 g-1. For the fish scale samples, the DPPH values ranged from 154.32 to 223.24 mg Trolox.100 g-1 and ABTS values from 13.70 to 16.34 mM Trolox.100 g-1. The best results for degree of hydrolysis, molecular weight and antioxidant activities were achieved with the Alcalase + Neutrase + Flavourzyme (ANF) enzyme combination. Samples obtained from fish skin and scales hydrolyzed with the ANF enzyme combination were found to contain the highest amounts of essential amino acids, also. Collagen hydrolysates obtained from sea bass fish scales and pangasius fish skin have high potential applications in food and pharmaceutical industry.