Physico-chemical and functional properties of proteins of tilapia (Orechromis mossambicus)

Abstract

The properties of total proteins from fresh tilapia (Oreochromis mossambicus) have been assessed. The meat had high moisture (81.34%) and low lipid (<1%) content. The nitrogen solubility index, with water as solvent, showed minimum solubility of 25.52% of total nitrogen at pH 6.0. The solubility profile of total proteins as a function of molar concentration of sodium chloride indicated maximum solubility at 0.8 M and thereafter it decreased. The total proteins comprised three different fractions as revealed by gel filtration profile. The high molecular weight component was more predominant. The sodium dodecyl sulphate polyacrylamide gel electrophoresis pattern revealed multiple bands in the molecular weight range of 205–18 kDa. Higher value of adenosine triphosphatase (ATPase) activity (4.1 µg Pi/mg of protein/min) obtained in the present study may be due to combination of sarcoplasmic and myofibrillar ATPase activity. High modori-inducing proteases (MIPase) activity at 55C was observed in the muscle extract that might interfere in the gelling ability. The gel-forming ability of tilapia meat was found to be moderate as indicated by large strain and small strain test.