Evaluation of theobromine content and the relationship between cocoa percentages in dark chocolates

Background: There are no specific regulations governing the labeling of dark chocolate or its bioactive component quantities.. The main alkaloid of the cocoa bean is theobromine. Chocolate is by far the main source of theobromine in the Western diet. To assess their effects on health, it is essential to understand the ingredients and composition of biologically active substances in chocolates available in stores.Objective: The present study aims to analyze the theobromine contents of commercial chocolates and evaluates the association between the labeled cocoa mass percentage (%), theobromine contents and evaluated non-fat cocoa solid (NFCS) parameters of dark chocolates. Materials and Methods: Several types of chocolates (bittersweet dark [60-80% cacao], semisweet dark [45-50% cacao], milk chocolate, and chocolate spreads) were analyzed using UV-Vis spectrophotometry with duplicate measurements.. Samples (n=20) typically 6 months apart from production dates have been selected. Results: Overall range for theobromine content varied from 1.9 to 9.6 mg/g. Of all, bittersweet dark chocolate had the highest (8.1±1.01 mg/g) concentration of theobromine in comparison to semisweet dark chocolate (6.4±0.79 mg/g). Milk-chocolate (2.7±0.26 mg/g) and chocolate-spreads (2.7±0.81 mg/g) had the lowest concentration of theobromine. A strong correlation between theobromine content and declared cocoa solid % was found in both of the dark chocolate categories (r = 0.523, p = 0.081 and r = 0.771, p = 0.009 for semisweet and bittersweet dark chocolate, respectively). NFCS indicated a correlation between the labeled cocoa solid % (R2 = 0.766) and the calculated cocoa solid % (R2 = 0.803) in dark chocolates. A high correlation has also been determined between the labeled cocoa solid percentage and the calculated cacao solid percentage in dark chocolates (R2 = 0.902).Conclusion: The labeled content of the cocoa mass of dark chocolates could be a preliminary information for the consumer about theobromine capacity.Keywords: Theobromine, chocolate, dark chocolate, cocoa-percentage, UV-Vis spectrophotometry