Stability of Individual Phenolic Compounds and Antioxidant Activity During Storage of a Red Wine Powder

Abstract

The addition of maltodextrin DE 10 to red wine (Cabernet Sauvignon) followed by freeze-drying allowed to obtain a free-flowing (dealcoholized) wine powder (WP) having a phenolic concentration about 3.6 times higher than the original liquid red wine. The powder, having a water activity (aw) of 0.053 and 0.330 was stored at 28 °C and 38 °C and the content of ten different phenolic compounds was determined by HPLC. Caftaric acid, quercetin 3-glucoside, caffeic acid, gallic acid and resveratrol contents in the WP stored at 28 °C and 38 °C, remained almost constant during 70 days of storage, while epicatechin gallate, catechin, malvidin 3-G and epicatechin showed slight losses (about 15-25 %) during storage. On the contrary, epigallocatechin experienced a strong loss of concentration (around 61% loss) during storage at the same conditions. A moderate decrease of antioxidant activity, determined by free radical scavenging capacity of the 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH*) and ferric reducing antioxidant power (FRAP) was observed along storage. This decrease was more important at higher temperature (38 °C) and higher aw (0.33). These results would allow the feasibility of using this WP as a healthy ingredient in alcohol-free powder drinks.