Paper Chromatographic Detection of Major Organic Acids in Fruit Juices

Abstract

Abstract The official AOAC paper chromatographic method for organic acids in vanilla extract has been modified slightly for fruit juices. Fruit juices are characterized by simple major organic acid patterns, so that addition of a foreign acid or cheaper fruit juices can frequently be detected by significant changes in the major organic acid pattern. A standard acid solution, developed simultaneously, provides a rough measure of the acid spot intensities. Eight collaborators participated in the examination of the two samples submitted. Two authentic juices were also provided for comparison purposes. All collaborators correctly found the unknown cherry juice to be adulterated with citric acid. Seven of the eight collaborators also reported correctly that the unknown blackberry juice was adulterated, although the acid pattern of this juice is more complicated and the addition of citric acid is more difficult to detect. The method is recommended for adoption as official first action.