Stability Evaluation of Anthocyanin Extracted from Processed Grape Residues

Anthocyanins are extremely important phenolic compounds due to their antioxidant potential. They are used as natural colorants in food industry, but upon the industrial processes, they show low stability. Grape and grape-made products are a source of several phenolic compounds and the residues proceeding from wine making may display a large amount of these compounds. The aim of this work was to evaluate the stability of anthocyanins extracted from grape residues industrially processed for wine making. For the evaluation, the residues of grapes Bordô and Isabel, which were extracted with ethanol 70% acidified to pH 2.0, were used. For stability analysis, the application of organic compounds co-pigments, such as caffeic, ferulic and p-coumaric acids at 0.5; 0.8; 1:1 (p/v) concentrations, was evaluated. The acid that showed higher stability was p-coumaric acid at a 1:1 (p/v) concentration, with 84.37% of retention time and half-life of 1,634 days. The use of these organic acids as stabilizers in solution increased anthocyanins useful lifetime.