Aldo Todaro - A method for anthocyanins extraction from fresh grape skin.

Version 1

      Publication Details (including relevant citation   information):

      Italian Journal Food   Science. 2003, 15, 337-346. ISSN: 1120-1770


      Tartaric and citric acid solutions were used to extract   anthocyanins (Acy) from fresh grape skins, in a non continuous   process, in order to obtain a prototype form of a natural   colorant. Solvent nature and concentration were significant   factors in the extraction operation, and tartaric acid was more   efficient than citric acid in both extraction yield and rate.   Comparative trials were conducted using sulphur dioxide and   acidified ethanol as solvents. The extraction yield and rate   using the optimal tartaric acid solution differed slightly from   those obtained with acidified ethanol but were higher than those   attained with sulphur dioxide. Total polyphenols,   proanthocyanidins and flavan content were determined in the   extracts obtained from the tartaric acid solutions. Solvent   concentration was not a significant factor for flavan extraction   yield and rate but was highly significant for the extraction of   the other compounds. The stability of the optimal prototype was   evaluated at four different storage temperatures and atmosphere   conditions. The combined effects of low pH of the extract (2.4),   low temperature (2.0°C) and modified atmosphere (N2)   provided a long shelf-life. Based on the results, a 0.75%   tartaric acid solution is recommended for Acy extraction from   fresh grape skin, and could substitute the widely used sulphur   dioxide

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