Formation of furfurals and degradation of bioactive compounds during microwave roasting of arabica coffee beans

In this study, the effects of microwave roasting process conditions (time and temperature) on Coffea Arabica beans physicochemical properties such as phenolic profiles, caffeine, hydroxymethylfurfural (HMF), Furfural (F), sugar degradation, browning index (BI) and antioxidant capacity were investigated. Convection roasting is the common method for roasting coffee, but this method negatively affects coffee. Therefore, in the present study, the microwave roasting method was applied. Its effect on (colour, dry matter content, total phenolic content, phenolic compounds, sugar degradation, HMF, F formation and sensory properties) L* value is a good indicator for determining the roasting degree of coffee beans. It decreased remarkably by increasing roasting temperature and time. HMF and furfural rose to a certain level but degraded remarkably by increasing time and temperature. A higher decomposing rate was determined for coffee beans roasted at higher temperature. Caffeine content increased by increasing roasting time and temperature. Total phenolic content and antioxidant activities of coffee beans had decreasing tendency according to roasting conditions. The kinetic study findings indicated that higher degradation rate constant values were calculated for the samples roasted at a higher temperature.