Effects of Protein-lipid Interactions on Physiochemical and Functional Properties of Food Proteins [microform]

"The results showed that pH, temperature and the type of lipids affected both ovalbumin-lipid interactions and physiochemical properties of ovalbumin. Changes in the electrophoretic behavior of ovalbumin were related to the presence of lipids, and the relative fluorescence of ovalbumin decreased in the presence of lipids at different pH values. In addition, lipids increased the stability of ovalbumin as revealed by the thermal denaturation (Td) and by the enthalpy transition (DeltaH). FTIR spectra in the amide I absorption region revealed that lipids affected the secondary structure of ovalbumin. Changes in the integrated intensity of the amide II band between (1520--1555) cm -1 in the presence of D2O showed that H-D exchange of ovalbumin decreased in the presence of lipids. Emulsifying properties, gel strength and water holding capacity (WHC) of ovalbumin increased significantly (P 0.05) in the presence of lipids. Scanning electron microscopy (SEM) showed difference in the microstructure of ovalbumin gel in the presence of different lipids. The more pronounced effect of lipids was observed with lecithin and the lowest was with stearic acid. The order of magnitude for the effects of lipids on physiochemical and functional properties of ovalbumin was: lecithin cocoa butter > oleic acid > linoleic acid > linolenic acid > stearic acid. It is likely that the degree of polarity of lipids play an important role in protein-lipid interactions and in the enhancement of the functional properties of ovalbumin." --