Effects of Encapsulated Fish Oil by Polymerized Whey Protein on the Textural and Sensory Characteristics of Low-Fat Yogurt

Five types of polymerized whey protein (PWP1, PWP2, PWP3, PWP4 and PWP5) containing different amounts of fish oil were added to low-fat yogurt as fat replacers. The texture, apparent viscosity, and sensory properties of the yogurts were analyzed in comparison with full-fat (3.0%, w/w, fat) and low-fat (1.5%, w/w; and 1.2%, w/w) milk yogurt controls. The majority (similar to 85%) of the particle size distribution was in the range of 1106 +/- 158 nm. Thermal property analysis indicated PWP was thermally stable between 50 degrees C and 90 degrees C. Yogurts formulated with 12% of PWP4 and 14% of PWP5 demonstrated higher firmness, springiness and adhesiveness (P<0.05), and lower cohesiveness (P<0.05) than the low-fat milk yogurt controls. There was no fat separation and they had less fishy smell. Yogurts incorporated with 12% of PWP4 had comparable sensory and textural characteristics to the full-fat milk yogurt control.