Modelling the transfer and degradation kinetics of aroma compounds from liquid media into coffee beans during simulated wet processing conditions

Abstract

Models of increasing complexity were developed to identify and represent mechanisms affecting the evolution of the concentration of 3 aroma compounds (2-phenylethanol, isoamyl acetate and butanal) usually produced by yeasts and transferred to coffee beans during the fermentation. Model parameters were identified from simulated wet treatment performed with four media (M1: dehulled beans, M2: demucilaginated beans, M3: depulped beans, M4: depulped beans with yeast), at 25 °C using labeled aroma compounds. The transfer of 2-phenylethanol was well described by a model including evolving resistance over time (R 2 = 0.98) while the accumulation of isoamyl acetate and butanal was better described by a model including two first order reactions in parallel (r 2 = 0.87–0.66 and r 2 = 0.80–0.67, respectively). The model development contributed to understand several mechanisms involved during fermentation such as the evolutive parchment resistance and the complex degradation reactions that take place simultaneously and have a significant impact on the compounds transfer. • Dynamic modelling of the transfer kinetics of aroma compounds in coffee beans. • Identification of complex mechanisms related to layer resistance and reactions. • Accurate prediction of the transfer of higher alcohols.