The effect of roasting method on headspace composition of robusta coffee bean aroma.

摘要

Robusta coffee beans were roasted by 3 methods: convectively at 230 degrees C for 590 s; by microwaves at 700 W for 670 s; and by the coupled convective-microwave method (simultaneous convective heating at 230 degrees C and microwaving at 700 W) for 370 s. The ultimate temp. of conventional, microwave and combined roasted beans was 238, 207 and 228 degrees C, respectively. Volatile compounds were determined in the headspace by GC-SPME, both in samples of roasted coffee and in green beans. 82 and 148 odorants were identified in green and roasted coffee, respectively. The highest contents of the latter were found in coffee roasted by the coupled method because both the relatively short time of roasting and moderately high final temp. of beans enhanced retention of volatile compounds. For the same reasons, contents of aroma compounds were lowest in convectively roasted coffee.