Preparation of fish protein isolate and hydrolyzate (Mugil cephalus) and their incorporation into Mexican foods.

Fish protein isolates (FPI) and hydrolyzates (FPH) were obtained from mullet (Mugil cephalus) through alkali solubilization and HCl precipitation for FPI, as well as enzymatic hydrolysis for FPH. The powdered products showed solubilities of 50 and 89%, and emulsifying capacities of 36 and 39 ml oil/100 mg for FPI and FPH, respectively, with protein contents of 90% and oil contents lower than 1.6%. Both products were used to enrich cereals and legumes in order to increase their protein content and quality. The resulting mixtures were used to prepare common Mexican dishes. When up to 20 and 35% of the total protein was provided by FPI and FPH, respectively, the dishes were well accepted by 70% of the panel.