Fortification of functional yogurt by the phytochemicals extracted from pomegranate peel

Food by products are good sources of phytochemicals. Phytochemicals can be extracted, using different methods and utilized in developing different foods. This research aimed to characterize the bioactive phytochemicals extracted from pomegranate peel and to examine the impact of the phytochemicals on the nutritional, physicochemical, and microbial quality of the fortified functional yogurt. In this study, ethanol, methanol, and acetone were used to characterize total phenolic, flavonoid, and anthocyanin contents and total antioxidant activity by the solvent extraction method. The ethanolic extracts showed a higher amount of total phenolic, flavonoid, anthocyanin contents and total antioxidant activity than the methanolic and acetonic extracts. The ethanolic extracts were used for the fortification of functional yogurt at 0.25 % (S1), 0.5 % (S2), and 0.75 % (S3), respectively, compared with the control (S4). Functional yogurt fortified by pomegranate peel extract contained a higher amount of total phenolic, flavonoid, anthocyanin, and antioxidant activity. The extracts also had a significant (*p ≤ 0.05) effect on lowering pH, reducing syneresis, and increasing water holding capacity, gross energy, yellowing index, titratable acidity and firmness throughout the storage periods. The survivors of Lactobacillus bulgaricus and Streptococcus thermophilus in the fortified yogurt were decreased. In case of sensory qualities, the fortified yogurts were almost identical to the control except S3 due to its pungent flavor. According to the findings, yogurt fortified with 0.5 % pomegranate peel was the best among the treatments, considering all parameters. This research gives an insight into optimizing yogurt fortification with pomegranate peel phytochemicals to improve its physicochemical and nutritional values.