Buffalo stirred yoghurt fortified with grape seed extract: New insights into its functional properties

Grape seed extract (GSE) is considered one of the major byproducts, which are rich in phenolic content and possess several health-promoting activities including antibacterial, anticancer, and antioxidant. The current research was devoted to improve the bioactive properties of stirred yoghurt through supplementation with GSE at three concentrations (0.1, 0.25, and 0.5 g/100 g yoghurt). The obtained stirred yoghurts were analyzed for determining their composition, pH, syneresis, viscosity, and sensory evaluation. Furthermore, some functional properties including antioxidant, antibacterial, anticancer activities were estimated. Significant increments (p ≤ 0.05) were observed in total solids, ash contents, pH, water holding capacity, and viscosity values, especially when 0.5% GSE was added. Moreover, adding 0.5% GSE showed higher (p ≤ 0.05) in vitro antioxidant, antibacterial, and anticancer activities. Interestingly, the improved bioactive properties resulting from adding GSE, even at the higher concentration, were not accompanied by any change in sensory properties. In particular, the color descriptor was mostly preferred by panelists when 0.5% GSE was added. The assessors did not observe any off-flavors in any of the tested stirred yoghurt samples. Therefore, the functional properties of stirred yoghurt could be improved by adding GSE preparation without affecting its organoleptic properties.