Study on the effect of roasting temperature on antioxidant activity of early-roasted Java']Java coffee powder (Arabica and Robusta)

The current consumer trend on seeking more health benefits of coffee consumption, mainly due to polyphenols content has led to the increasing popularity of green coffee beans extract or green coffee products. These products include green (raw-unprocessed) coffee powder, which is directly brewed and/or consumed. There is a safety concern in relation to consumption of raw-unprocessed coffee. Meanwhile, high temperature roasting may have influence on the functional properties of coffee, particularly its polyphenols. The objective of this research is to study the effect of roasting temperature at the early roasting stage (95 degrees C, 125 degrees C, and 165 degrees C) on the antioxidant activity of two coffee species, i.e. Java Arabica and Java Robusta. The non-roasted coffees were evaluated for comparison. The IC50 and total phenol were analysed in triplicates. The results showed that Arabica and Robusta coffee powders were significantly differ on the antioxidant activity, where Robusta showed the highest activity as compared to Arabica. The application of heating on coffee beans during roasting tends to decrease antioxidant activity. However, there was a fluctuation where antioxidant activity of coffee reached a peak at early roasting temperature of 95 degrees C.