Low-calorie functional dairy dessert enriched by prebiotic fibers and high antioxidant herbal extracts: A study of optimization and rheological properties.

The formulations of functional low-calorie dairy dessert, enriched with inulin/polydextrose (as a starch substitute), and ginger/cinnamon extract (as a flavor component and natural antioxidants), were developed and optimized by the D-optimal mixed design method. In the first stage, using the hedonic sensory evaluation and syneresis data, the optimal concentrations of inulin and polydextrose were obtained as 2.49% inulin and 1.51% polydextrose, respectively. The steady shear rheological test showed that the replacement of starch with inulin and polydextrose caused a decrease in apparent viscosity in all dessert samples. This decrease was higher in the samples containing polydextrose than those containing inulin. The replacement of starch with inulin and polydextrose also reduced the hysteresis loop area and thixotropic behavior. In the second stage, 0-0.4% of ginger and cinnamon extracts  were added to the optimum sample and then the antioxidant and color properties of dessert samples were evaluated. The lightness (*) Hunter parameter decreased by adding extracts and the samples containing cinnamon extract showed a higher * parameter than the control and ginger-incorporated samples. The result of the 2,2-diphenyl 1-picrylhydrazyl (DPPH) antioxidant assay showed that the antioxidant capacity of ginger extract was significantly higher than that of cinnamon extract. The half-maximal inhibitory concentration (IC50) value of dessert samples decreased by adding 0.4% cinnamon and ginger extracts from 88.30 mg/mL to 77.04 and 31.94 mg/mL, respectively.