Employment of different processes for the production of strawberry vinegars: Effects on antioxidant activity, total phenols and monomeric anthocyanins

The use of strawberry surpluses for the production of added value products seems to be a good solution choice to avoid the waste of this fruit. We produced strawberry vinegars through double fermentation (alcoholic and acetous) from three different harvests of Fragaria x ananassa var. Camarosa. The objective was to study the evolution of antioxidant activity, total phenols and monomeric anthocyanins during the vinegar production process. These parameters increased when sulphur dioxide and pectolytic enzymes were added to substrates. Inoculation with the Saccharomyces cerevisiae strain RP1 produced wines with half the anthocyanins with respect to the spontaneous fermentations. The use of wood barrels, particularly cherry wood barrels, had a positive effect on all the parameters determined. All measured parameters decreased during the double fermentation process. In general, the acetification stage led to a high loss of antioxidant compounds. Moreover, the production of these vinegars at a semi-pilot scale yielded final commodities with the best values for antioxidant activity, total phenols and monomeric anthocyanins comparing with the vinegars obtained in 2008 and 2009 harvest.