Physical and Sensory Properties of Yogurt Stabilized with Milk Proteins

Abstract

Abstract Eighteen skim milk yogurts, prepared from all combinations of six protein types (three casein- and three whey-based products) and three protein concentrations (.05, 1.0, and 1.5% added protein), were compared by four physical and four sensory characteristics. Addition of increasing amounts of protein increased gel firmness and decreased syneresis. The gelatin control (.5%) had the least syneresis, followed by sodium caseinate (1.5%). Generally, the casein-based yogurts were firmer with less syneresis than yogurts based on whey protein. The casein-based proteins, particularly sodium caseinate, produced yogurts that were generally inferior to gelatin for smoothness and appearance. Whey protein concentrates, at 1.0 and 1.5% of protein addition, produced yogurts generally superior to casein-based products for both appearance and smoothness. Treatment effects were significant for all variables except pH. The interaction between protein type and protein percent was significant for measured gel firmness, titritable acidity, smoothness and appearance but was not significant for syneresis, pH, sensory firmness, and sensory acidity. The correlation between sensory firmness and syneresis was —.82 for the 18 experimental treatments, and the correlation between measured gel firmness and syneresis was —.66.