Effect of Skimmed Milk Powder and Fruit Jams Addition on the Physicochemical Characteristics of Yogurt

In three consecutive experiments, natural yogurt (NY) and fruit yogurt (FY) fortified with 5 and 10% skimmed milk powder (SMP) and 10% jam from black currant (BC), elderberry (EB), and their mixture of 1:1 (BCEB) were analyzed, and consumer acceptance was assessed. In Experiment 1, the effect of SMP (0, 5, and 10%) on selected physicochemical parameters of the NY was evaluated. With the increasing addition of SMP, a decrease in fat content (up to -19%) and, conversely, an increase in protein content (up to +82%) and viscosity were noted. Analyses of fruits and jams intended for yogurt fortification revealed a significantly higher vitamin C content in BC than in EB and higher anthocyanins in EB than in BC. In Experiment 2, NY with 5 and 10% SMP was fortified with 10% jams (BC or EB). A joint effect of SMP and the type of fruit jam was evaluated. The same trends in fat and protein contents as in Experiment 1 were detected. The sensory evaluation showed better acceptance of FY with 10% SMP and no differences between BC and EB perception. Thus, for Experiment 3, FY was prepared with only 10% SMP and 10% jam (BC, EB, BCEB). Significant differences were detected in active acidity and color measured in the CIELab system. These results were also confirmed in sensory evaluation. The overall acceptability showed that FY with different types of jam did not significantly differ. The launching of innovative fortified yogurt onto the market represents a promising way to increase the diversity of fermented dairy products with nutritionally desirable properties.