Pacific whiting (Merluccius productus) underutilization in the Gulf of California: Muscle autolytic activity characterization

In México’s Northwest coast, Pacific whiting (Merluccius productus) is considered an under-utilized species because of its high tendency to become parasitized, thus promoting a high proteolytic activity present in muscle tissue. Sample fish for study were separated in lots by degree of parasitism in “apparent” parasitized (APP) and advanced parasitized (ADP). Thus, pH and temperature conditions of mayor endogenous proteolytic activity in muscle were determined. Maximum activity was detected at 50 °C (pH 3.5–4.0) and at 60 °C (pH 6.75–7.0). Parasitism degree had a significant effect in enzyme activity at acidic pH (p < 0.05) being higher in APP at low temperature (30 °C). Higher temperatures (40–50 °C) favored (p < 0.05) activity in ADP muscle (same pH range) with the highest (p < 0.05) observed at 50 °C at pH 3.5. No much difference was observed at pH 7.0–8.0. Results suggest that pH around physiological conditions at 60 °C could be used as an advantage in fish protein hydrolysate production or as processing aid where a protein hydrolysis is required.