Chemical composition and sensory profile of the Italian espresso coffee powder and beverage under different roasting conditions

The Italian espresso coffee is a very popular drink worldwide. Roasting of coffee grains represents a key step in the development of the beverage characteristics and aroma. A coffee blend (80% Coffea arabica and 20% canephora ) of a well-known Italian coffee firm underwent 3 roasting conditions (standard with end temperature of 216 °C, below standard with end temperature of 206 °C and over standard with end temperature of 223 °C) to study the effects of processing conditions on the chemical composition of the coffee powder and on the chemical and sensory characteristics of the espresso beverage. Proximate composition, polar and semi-polar metabolome (amino acids and aliphatic acids), chlorogenic acids, and volatile organic compounds were determined in the powder and beverage by means of standard methods, HPLC-ESI(±)-HRMS, HPLC–PDA/ESI–MS and HS-SPME/GC–MS respectively. Changes induced in the powder and beverage by roasting conditions are described with heatmaps and correlation networks between polar metabolites and sensory characteristics of the espresso beverage are reported. The concentration of chlorogenic acids is inversely proportional to the roasting temperature and the lower is the roasting temperature, the higher is the acid taste in the espresso. Some volatile organic compounds might be analytical markers of the strength of the roasting process. Cream and body of drink are increased as roasting temperature increases.