Analysis of proanthocyanidin cleavage products following acid-catalysis inthe presence of excess phloroglucinol

The analysis of proanthocyanidin cleavage products after acid-catalysis in the presence of excess phloroglucinol was investigated. In the developed an alytical method, a solution of 0.1 N HCl in methanol, containing 50 g/L phl oroglucinol and 10 g/L ascorbic acid was prepared. The proanthocyanidin of interest was reacted in this solution (5 g/L) at 50 degreesC for 20 min, an d afterward combined with 5 volumes of 40 mM aqueous sodium acetate before analysis by reversed-phase HPLC using an aqueous acetic acid and methanol g radient. This procedure was used to investigate the composition of proantho cyanidins isolated from the seed and skin tissue of Vitis vinifera L, berri es. The results compared favorably to results obtained when benzyl mercapta n was used as the trapping nucleophile, indicating that phloroglucinol is a n effective reagent for this analysis.