Effect of heat treatment on physicochemical and sensory properties of selected coffee varieties

摘要

Coffee is one of the mostly consumed beverages worldwide. Roasting of coffee is an important process causing many changes in the quality and sensory characteristics of coffee beans. The objective of this study was the determination of the effect of roasting on the physicochemical and sensory properties and comparison of six coffee varieties, namely Brazil Santos, Brazil Rio Minas, Mexico Finca Muxbal, Guatemala Shb Ep, Ethiopia Djimmah, and India Robusta. Coffee beans were subjected to heat treatment at air temperatures up to 270 degrees C for up to 20-27 min, depending on the coffee variety and the desirable roasting degree. During the whole process, various physicochemical properties (mass, volume, density, color) and sorption isotherms of coffee beans were measured. For sensory evaluation, arabian and espresso beverages were prepared. Color of coffee beans darkened with increasing time and temperature during roasting, while volume increased. Total mass loss was also observed. Sorption isotherms followed type III, except for the variety India Robusta and the raw samples that followed type II. Sensory characteristics were distinctly different for each of the studied varieties. In arabian coffee drinks the color of cream was darker compared to espresso drinks and presented less acid and sour taste. Concerning texture, the body was positively evaluated both in arabian and espresso drinks. [GRAPHICS] .