Effect of Thermal Modification on Physicochemical and Functional Properties of Myofibrillar Proteins from Tilapia, Oreochromis mossambicus (Peters, 1852)

The effect of thermal modification on the physico-chemical and functional properties of myofibrillar proteins (MFP) extracted from Tilapia, Oreochromis mossambicus (Peters, 1852), heated over a temperature range of 3 to 55oC was evaluated. The protein solubility in solution decreased with increase in temperature, with a steep decline at 40oC. The decrease in protein solubility was proportional to increase in both cis parinaric acid and 8-anilino-1-naphthalene sulphonic acid hydrophobicity. Ca2+ ATPase activity decreased as the temperature increased, correlating with increase in surface hydrophobicity and decrease in solubility. Total and reactive sulphydryl group, showed an inverse relation to viscosity and turbidity of the MFP suggesting aggregation/unfolding of the proteins. Emulsion activity index significantly increased (p<0.05) as the temperature increased upto 40oC. The emulsion stability of the proteins increased gradually with temperature while foam expansion decreased upto 35oC, thereafter increasing steadily. Foaming properties of the fish protein also improved tremendously on thermal modification.