Spray Drying Formulation of Polyphenols-Rich Grape Marc Extract: Evaluation of Operating Conditions and Different Natural Carriers

The efficiency of maltodextrin, whey protein isolate, and pea protein isolate to formulate a polyphenol-enriched grape marc extract by spray drying has been compared. Different inlet (120-140 A degrees C ) and outlet (81-89 A degrees C ) temperatures have been evaluated, as well as the amount of carrier expressed as carrier/extract ratio (0.1:1-1:1). The particles obtained were characterized in terms of their chemical composition, morphology, cytotoxicity, and cellular antioxidant activity. Outlet temperature was observed to have a higher influence on the particles than inlet temperature. A 22 % loss in total phenolic content was observed when the extract was spray dried without any carrier material, whereas the addition of the lowest amount of carrier lowered this value (< 12 %). While all the carriers tested showed high phenolic retention results, whey and pea protein outperformed maltodextrin in terms of total phenolic and anthocyanin content; in particular, the particles obtained with the lowest carrier/extract ratio presented the highest phenolic and anthocyanin concentrations per gram of product while maintaining a high phenolic recovery (> 87 %). Whey protein showed an enhancement of the chemical and cellular antioxidant activity per unit mass of gallic acid equivalent when compared to the other carriers.