Total Polyphenol Content of Green, Roasted and Cooked Harar and Yirgacheffee Coffee, Ethiopia

The effect of solvent composition on the total polyphenols content of green, roasted coffee and traditional coffee beverage preparation stages (Abol, Tona and Bereka) were studied by UV-Vis spectroscopy. The maximum extracted polyphenol of 640.3 mg GAE/100 g and 641.9 mg GAE/100 g were obtained at Harar and Yirgacheffee green coffee extracts with at 85% methanol, respectively. The results showed that total phenolic contents of extracts were found to be in the order of green> roasted >cooked (Abol>Tona>Bereka) in both coffee samples. Application of ANOVA revealed that a significant variation (p <0.05) was noted between the green, roasted, Abol, Tona and Breka coffee processing procedures. In general, this study revealed that there was a loss of substantial amount of total polyphenols through the traditional way of coffee brewing, probably ascribed to continuous provision of heating leads to degradation of existing polyphenols and formation of less stable and volatile products.