Probiotic yoghurt fortified with rosehip seed powder: Viability, physicochemical, and sensorial properties

The impact of rosehip seed powder (RSP) fortification (1, 2, and 3%) on some physicochemical characteristics and bacterial survival of set type probiotic yoghurt was evaluated during 21-d storage at 4°C. Textural, microstructural, total phenolic content, antioxidant activity, and sensorial attributes were also assessed in the samples, with and without RSP fortification. Milk was fermented by yoghurt cultures with the inclusion of the probiotic cultures comprising Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis. The total solid, protein, and total phenolic contents in yoghurts fortified with RSP were significantly higher than control, and an enhancement in the yoghurt's antioxidant capacity and firmness, while a reduction in yoghurt's adhesiveness and syneresis occurred (p < 0.05). However, sensory scores were lower in RSP-fortified yoghurts than in control. Throughout 21-d storage, the yoghurt's titratable acidity increased while its syneresis and pH decreased. The present work also determined that RSP fortification of probiotic yoghurt increased (p < 0.05) in L. acidophilus and B. animalis subsp. lactis growth (up to 8.24 and 8.10 log CFU/g, respectively) as compared to their respective controls (7.84 and 7.83 log CFU/g, respectively), and probiotic counts in yoghurts fortified with RSP remained over 6 log CFU/g at the end of storage. The documented knowledge of fortifying probiotic yoghurts with RSP could inspire the dairy industry to generate a novel synbiotic product while utilising wasted rosehip seeds as processing waste.