Functional enhancement of stirred yogurt with vacuum-dried red grape pomace: impact on quality attributes

By-products of fruit processing can serve as sustainable ingredients for developing innovative dairy products. In this study, red grape pomace powder (RGPP) was incorporated at 1%, 2%, and 3% (w/w) into stirred yogurt to enhance its colour and increase its dietary fiber and polyphenol content, thereby creating a novel functional yogurt. The yogurt samples’ physicochemical characteristics, such as colour measurements, pH, acidity, syneresis, and water-holding capacity (WHC), were assessed, along with their textural qualities after 1, 14, and 28 days of refrigeration (4 °C). Organoleptic analysis was also performed, alongside quantification of total phenolics, total anthocyanins, and antioxidant activity in the yogurts. The findings revealed that RGPP provided a significant amount of dietary fiber and polyphenols. The addition of RGPP increased WHC, total phenolics, total anthocyanins, and antioxidant activity, while also giving the yogurts a pleasing red hue and reducing syneresis. Furthermore, the textural qualities were enhanced by RGPP addition, indicating that a denser and more stable yogurt gel network was formed compared with the control. Regarding colour, consistency, flavour, and overall acceptability, the yogurt enriched with 2.0% RGPP received the highest scores. Therefore, RGPP may be incorporated into yogurts to enhance their nutritional and functional value, providing a promising strategy for the valorisation of fruit-processing by-products and contributing to more sustainable dairy innovation.