Valorization of Almond Pomace to Improve the Physicochemical, Microbial, and Antioxidant Properties of Yoghurt Drinks

Almond pomace (AP) is an underutilized agro-industrial byproduct rich in nutrients and bioactive compounds. This study evaluated the effects of AP incorporation (1 and 2% (w/v), added before or after fermentation) on composition, water-holding capacity (WHC), viscosity, microbial viability, total phenolic content (TPC), and antioxidant activity of yoghurt drinks over 14 days of cold storage at 5 °C. A significant dose-dependent increase (P < 0.05) in total solids, protein content, WHC, and viscosity was observed, while pH decreased (ranging from 4.88 to 4.34) with the added AP levels and storage time. The prefermentation addition of 2% AP enhanced the viability of yoghurt culture, particularly Streptococcus thermophilus, throughout storage. AP-fortified yoghurts also exhibited significantly (P < 0.05) higher TPC (ranging from 83.27 to 99.55 mg GAE/100g) and antioxidant activity (ranging from 35.98 to 43.20%), which occurred in a dose-dependent manner. Overall, almond pomace is a promising sustainable ingredient for producing antioxidant-enriched yoghurt drink while valorizing food-processing byproducts.