Effect of Roasting Conditions on Concentration in Elements of Vietnam Robusta Coffee

Vietnam Robusta Coffee was roasted at different roasting degree and roasting temperature and 9 element concentrations (K, Mg, Ca, Na, Fe, Cu, Mn, Zn and Pb) of roasted coffee were analyzed by Flame atomic absorption method (FAAS) in this study. The results showed that the concentrations were ranged in 1447.97 ~ 1342.10 (mg/100g), 768.22 ~ 1259.44 (μg/g),10.35 ~ 13.15 (μg/g), and 17.38 ~ 20.97 (μg/g) for element of K, Ca, Cu and Mn in green and roasted coffee beans, respectively. All determined elements were the smallest value in green coffee, then increased with increasing roasting level and reached the highest value in Spain roast (roasting temperature of 250°C). Mg concentration ranged in 682.70 ~ 3647.73 (μg/g); Fe concentration ranged in 37.20 ~ 53.44 (μg/g); Zn concentration ranged in 5.97 ~ 6.89 (μg/g) and Pb concentration ranged in 2.18 ~ 15.04 (μg/100g). Concentrations of all determined elements didn’t change with the increased roasting process.