Optimized method for simultaneous determination of catechin, gallic acid, and methylxanthine compounds in chocolate using RP-HPLC

Abstract.

The simultaneous determination of catechins, gallic acid, and three methylxanthine compounds was determined in chocolate extract by reversed-phase HPLC. An isocratic HPLC procedure using Hypersil-ODS column with methanol three distilled water–formic acid (48.75:200.5:0.75, v/v/v) as a mobile phase was used and the HPLC profiles of 11 chocolate products were obtained. (–)- Epicatechin, (–)-epigallocatechin gallate, levels were very high whereas (+)-catechin, (–)-epigallocatechin and (–)-epicatechin gallate were lower values. Gallic acid was predominant compounds with extremely high levels in all chocolate samples. The content of three methylxanthine, theobromine, theophylline and caffeine was quantified with this procedure. Caffein amounts were low in all samples, while theobromine levels were high in milk and dark chocolates. Theophylline was at trace levels in some chocolates and could not be detected in some samples. This method was reliable, reproducible and objective for quantitative identification of flavanols and alkaloid compounds in the chocolate industry.