Use of Methanolysis for the Determination of Total Ellagic and Gallic Acid Contents of Wood and Food Products

Abstract
Anhydrous methanolic HCl has been found to be an excellent reagent for releasing ellagic acid and gallic acid (as methyl gallate) from biomass substrates. Optimization of both the reaction conditions and the gradient HPLC analysis has led to the development of a new protocol. The method provides ellagic acid yields significantly higher than those obtained previously, indicating total ellagic acid contents of several substrates have previously been underestimated. Keywords: Ellagic acid; gallic acid; HPLC; ellagitannins; methanolysis; methyl gallate