Development of a potential functional yogurt using bioactive compounds obtained from the by-product of the production of Tannat red wine

Tannat (Vitis vinifera cv. Tannat) grape pomace is an abundant by-product of the Uruguayan wine industry, which is mainly composed of peels and seeds. Tannat skin from grape pomace is a sustainable source of bioactive compounds and dietary fiber. In previous studies we have seen that it has antioxidant, antidiabetic, antiobesity and anti-inflammatory activity, with the potential to prevent the development of chronic diseases. In this work, the encapsulation of bioactive compounds of an ethanolic extract derived from Tannat grape skin by microparticles of whey protein isolate (without and with enzymatic hydrolysis) and inulin (3:1) is proposed, for its application in yogurt as a potential functional food. In addition, it is proposed to evaluate the bioaccessibility of the bioactive compounds for which an in vitro digestive simulation study is carried out simulating the conditions of the gastrointestinal tract. Among the most relevant results, it was found that the encapsulation efficiency was higher for the encapsulant without hydrolysis (29.7%). The incorporation of the encapsulated bioactive compounds in yogurt resulted in a significant increase (p<0.05) of antioxidant capacity by ORAC-FL compared to the controls. Also, after in vitro digestion, the extract did not lose antioxidant capacity (determinated by ABTS and ORAC-FL) and the different yogurt formulations have antioxidant capacity. In conclusion, spray drying is a suitable methodology for encapsulating Tannat grape skin extract for its application in yogurts as a natural colorant and antioxidant ingredient.