INFLUENCE OF ACID AND BASE HYDROLYSIS ON THE PHENOLIC COMPOSITION OF RED RASPBERRY JUICE

Acid and base hydrolysis simplified the complex HPLC chromatographic p rofile of red raspberry juice phenolics dramatically. In three acid-hy drolyzed juices, ellagic acid, two unidentified ellagic acid compounds , and gallic, p-hydroxybenzoic, protocatechuic, caffeic, p-coumaric, a nd ferulic acids, as well as (+)-catechin, (-)-epicatechin, quercetin, and kaempferol were separated and identified using HPLC diode array s pectral techniques. The percentages of HPLC peak area for these phenol ics were similar in the acid-hydrolyzed juices. In base-hydrolyzed sam ples the same phenolics, except the second ellagic acid compound, were present, and the first ellagic acid compound was present in smaller q uantity. Sep-Pak C18 cartridges were used for sample preparation. Hydr olysis could become a very useful tool for rapidly screening raspberry juices for qualitative deviations from authentic HPLC profiles to det ermine adulteration by other fruit juices or phenolic mixes.