Effects of post-harvest process on volatile-sensory profile for coffee in Colombia

Abstract

The coffee fermentation process has been established as a determining stage regarding its quality and aroma. The objective of this study was to evaluate the differences that exist between five fermentation processes and within each process (at different fermentation times) based on their volatile and sensory profile. The processes evaluated were dry or natural (NA), semi-dry or honey (HO), and three variations of the wet process, called: conventional aerobic (CA), aerobic with previous fermentation in cherry (AFC) and anaerobic with previous fermentation in cherry (ANFC). The NA process obtained the highest score (86.63) in the sensory profile and statistically different from the other processes, followed by the process HO (84.79), ANFC (84.24), CA (84.21) and AFC (83.63). The volatile profile was determined by headspace solid phase micro-extraction (HS-SPME) and gas chromatography coupled to mass spectrometry (GC-MS). Fifty-one volatile organic compounds (VOCs) were tentatively identified. The main chemical families that allowed differ-entiating between groups of processes were ketones and pyrroles, and the VOCs that mainly contribute to differentiate between process or groups of processes are: ethanone, 1-(1H-pyrrol-2-yl)-, 2,5-dimethylpyrazine, 2-furanmethanol, 4-vinylguayacol, 2-methylfuran, 2-butanone, 2,3-dimethylpyrazine, acetylpyrazine, 1-(2-furanylmethyl)-1H-pyrrole and 2,2’-bifuran. Within each fermentation process (between treatments) no differences were found from the final score of the sensory analysis, but differences were found from volatile profile.