MICROSTRUCTURE OF WHEY-PROTEIN ANHYDROUS MILKFAT EMULSIONS

Research has been undertaken in order to determine the microstructure of emulsions consisting of whey proteins and anhydrous milk fat. The results revealed that whey protein films were formed at oil/water interfaces. Scanning electron microscopy (SEM) analysis of chemically fixed specimens, and cryo-SEM analysis of partially etched, frozen specimens revealed that the adsorbed protein layer (coating the fat droplets) had a granular, aggregated appearance. Emulsions with a high fat load prepared under high homogenization pressure exhibited a bimodal particle-size distribution. Clustering of the protein-coated droplets, and sharing phenomena at the oil/protein interfaces were evident in these emulsions. The structural analysis indicated that the bimodal distribution could be attributed to clustering of protein-coated fat droplets rather than to coalescence.