Coffee-roasting variables associated with volatile organic profiles and sensory evaluation using multivariate analysis.

A multivariate analysis investigated the operational variables of a professional roaster, the volatile chemical composition of roasted specialty coffee and how they correlate with the sensory evaluation of the final beverage, which directly affects the commercial value of the product. The experimental planning elicited 38 distinct roasting profiles that variegate (i) drum initial temperature (160 and 200°C); (ii) drum air-flow ventilation opening (25-50-100 and 25-75-100 %-numbers show the percentage of opening for ventilation throughout the roasting); (iii) drum rotation speed (40 and 65 rpm); (iv) fuel gas flow/pressure increase into burners (0.5 and 1.0mbar min^-1); (v) roasting time after bean cracking (1.0 and 2.0min). After roasting, 108 volatile organic compounds (VOC) were measured by SPME-GC-MS in the aroma of the roasted coffees. Principal component analysis (PCA) correlated VOC profiles, the operational variables of the coffee roaster and sensory evaluation. PCA from either sensory or chemical analysis data indicated...