Effect of incubation time and pH on the protein characterization of the aqueous soluble phase of acidified mackerel by-product

Abstract

This study aimed to evaluate the protein content from aqueous soluble phase (ASP) of mackerel by-product with a variation of time and pH. Mackerel by-product was hydrolyzed by different incubation time (0, 15, 30, and 45 h) and pH (3.2, 4.2, 5.2, and 6.2) to produce ASP. The study conducted on a completely randomized design (CRD) followed by the Tukey test. The different incubation times and pH showed a significant effect (P<0.05) on yield, crude protein, and soluble protein of ASP. The pH and yield values of ASP in the range of 4.1 to 6.3 and 11.16% to 30.69%, respectively. The crude protein and soluble protein content ranged from 1.28% to 3.27 %, and 0.98 g/L to 2.1 g/L, respectively. The highest yield and crude protein of ASP was under pH 3.2 for 15 h. The amino acid analysis showed that several amino acids were detected in considerable amounts in the ASP. This study indicated that the ASP of mackerel by-product could be a potential material of fish peptone for bacterial growth media.