Combined changes of process conditions improved aromatic properties of Vietnamese Robusta

The flavor and taste of coffee are affected by roasting conditions and extraction temperature. This study assessed changes in the flavors and tastes of coffee extracted from Vietnamese Robusta with different roasting times and temperatures, as well as different extraction temperatures. Vietnamese Robusta green beans were roasted for different times ranging from 5 to 20 min and at different temperatures ranging from 100 to 250°C. The roasted coffee was then extracted at five different temperatures ranging from 90 to 120°C. The coffee flavor was evaluated in terms of 5 key odorants: guaiacol; 4-ethylguaiacol; 2-ethyl-3,5-dimethylpyrazine; 2,3-diethyl-5-methylpyrazine, and 2-furfuryl. The taste of coffee was evaluated in terms of 6 main compounds that confer bitterness and sourness: caffeine, trigonelline, chlorogenic acid and citric acid, acetic acid, formic acid. The optimized roasting and extracting conditions were identified that 200 g of VN Robusta green beans, roasting at 230°C for 18 min, and then extracted with Espresso Machine at 110°C.