Emulsifying capacity of coconut proteins as a function of salt, phosphate, and temperature

Nitrogen solubilities of proteins in defatted coconut flour (CF) and coconut protein concentrate (CPC), prepared by ultrafiltration, were determined in water and 2% NaCl. The effect of temperature, disodium phosphate, and salt on emulsifying capacities (EC) of these products also were investigated by a model system. Between pH 4.0 and 5.0, nitrogen solubilities of CF and CPC in water were lower than those in salt solutions. In salt solutions, the nitrogen solubility was lowest at pH 1, and increased steadily as pH increased from 3.0 to 6.0. CF had higher EC values than CPC at all salt and phosphate levels. Additionally, increased phosphate level generally increased the EC at both salt levels, but these increases were not significant at 0.9% phosphate level as compared to the 0.7% phosphate level ( P <0.05). Although the emulsifying temperature of 40°C showed higher EC values than both 60 and 80°C at all salt and phosphate levels, the overall temperature effect was not significant ( P >0.05). However, EC decreased significantly with the addition of salt at all phosphate levels.