Influence of roasting levels on chemical composition and sensory quality of Arabica and Robusta coffee: a comparative study

This study investigated the impact of roasting profiles on the chemical and sensory characteristics of coffee beans (C. canephora and C. arabica). Different roasting times and temperatures were analyzed to understand their influence on physicochemical properties, concentrations of sugars, organic acids, and melanoidins. The research aimed to associate chemical compositions with sensory characteristics to identify roasting profiles resulting in more appreciated coffees. Results revealed connections between sugars, organic acids, and melanoidins with specific roasting profiles. Succinic acid showed the highest concentration in C. canephora at 210 °C/11.01 min, along with the highest concentrations of organic acids in that roasting profile and species. Fructose reached its highest concentration in the 210 °C/11.01 min roast, along with the highest melanoidin content. Spectral analyses highlighted bands associated with chlorogenic acids, lipids, and carbohydrates in coffee. Expert sensory evaluation indicated significant differences, with arabica coffee being more positively evaluated than C. canephora, especially in the roasting profiles at 135 °C/20.20 min and 230 °C/17.43 min. Consumer evaluation also revealed discrepancies in perceptions of acidity, sweetness, aroma, flavor, and overall impression between varieties and roasting profiles. C. arabica received higher scores in the overall impression, except in the 230 °C/17.43 min roasting profile, which showed no significant differences between species. Principal Component Analysis (PCA) contributed to understanding the relationship between coffee species, roasting profiles, and sensory attributes. This analysis allowed for the visualization of sample clusters and the identification of key influences on data variations, explaining 60.3 % of the variation present in the samples.