Antioxidant Capacity of Selected Teas and Cocoa

James Hankemeyer, Kasey Rivera, Kelnisha Lightbourne, Sara Salamah, and Luis C. Fernandez-Torres

School of Science, Technology, and Engineering Management, St. Thomas University, Miami Gardens, FL 33054

Diverse teas are consumed around the world for their calming, soothing effects. Many people attribute curative properties to tea. The same can be said for cocoa, and its processed form chocolate. Furthermore, these attributed health-giving properties are suggested to come from their antioxidant properties. This study presents the determination of the antioxidant capacity of selected teas (Camellia sinensis) and cocoa (Theobroma cacao), and comparing those results to a caffeine standard. The Briggs-Rauscher (BR) oscillating reaction was used to determine the antioxidant capacity of the samples. The antioxidant species scavenge free radicals formed in the BR reaction, lengthening the time intervals of the reaction’s oscillations; the higher the antioxidant capacity, the longer the oscillation delays. The samples consisted of aqueous preparations of Green tea, Black tea, Cocoa (pure powder), and Dark chocolate. To analyze the results we used the Relative Antioxidant Performance (RAP), where the slopes of the samples were compared to the caffeine standard. We hypothesized that the aqueous preparations of the samples would exhibit antioxidant capacity. Our hypothesis was proven correct, with green tea showing consistently higher RAP than decaffeinated green tea, and dark chocolate exhibiting slightly more antioxidant capacity than pure cocoa powder. Black tea proved to be less antioxidant than green tea. These observations suggest that antioxidant properties are present, and could be a plausible pathway to their attributed health-giving properties. Finally, these preparations are complex mixtures of natural ingredients; therefore, we should not dismiss any potential synergistic effects between different ingredients.