Influence of storage conditions on phenolic compounds stability, antioxidant capacity and colour of freeze-dried encapsulated red wine

Abstract

A concentration of 9% (w/w) maltodextrin (DE 10) and gum arabic was added to red wine C. sauvignonand freeze dried to obtain a dealcoholized wine powder having a polyphenols concentration 7.1 timeshigher than in liquid red wine. Malvidin 3-G and total anthocyanins were the phenolics showing greaterlosses during storage. Moreover, an increase of water activity from 0.11 to 0.58 greatly enhanced thelosses. The decrease in malvidin 3-G content was associated with the decrease on redness (colourparameter a*) of wine powder. Gallic acid was the most stable phenolic and its content remained constant during storage at all water activity levels under investigation. Contents of epicatechine, catechine, caffeic acid and resveratrol remained constant at aw = 0.11, although at aw = 0.33 catechine and epicatechine suffered important losses. Results indicated that water activity was a key factor affecting phenolics stability during storage.Antioxidant activity of the wine powder remained constant over 145 days at accelerated storage conditions.