Characteristics and Use of Yellow Stripe Trevally Hydrolysate as Culture Media

Characteristics and the use as culture media of protein hydrolysate from yellow stripe trevally (HF25) were determined in comparison with Bacto Peptone. HF25 had the higher contents of ash (45.73%), lipid (0.77%), and moisture (4.34%) but lower protein content (42.11%) than did Bacto Peptone (P < 0.05). HF25 powder was slightly darker than Bacto Peptone (P < 0.05). HF25 contained a higher amount of essential amino acids (44.05%) than did Bacto Peptone (19.34%). HF25 and Bacto Peptone consisted of several minerals at varying levels and had an excellent solubility over a wide pH range. At water activity (a(w)) greater than 0.75, the much higher moisture sorption was found in HF25 (P < 0.05). HF25 showed the higher bacterial productivity ratio than did Bacto Peptone (P < 0.05). When HF25 and commercial Bacto Peptone were used as microbial media to determine microbial load of environmental and food samples and pathogenic bacteria, HF25 generally exhibited similar potential in culturing those microorganisms (P > 0.05). Thus, the conversion of low market value species to fish protein hydrolysate, which can be used as the nitrogenous substrate for microbial growth, could be achieved.