BASQUE RESEARCH
 Basque research, development and innovation web site

News

Contact:

Mª Isabel Solana García

Universidad de Navarra

Contact details:

noticias@unav.es

(+34) 948425600

2004/2/11

Study of espresso coffee quality

The preparation of Espresso Coffee (EC) is influenced by factors related to the coffee and water and other technical conditions related to the machine. Susana Andueza has presented her doctoral thesis about Influence of technological variables on espresso coffee quality. Antioxidant and pro-oxidant capacity of coffee in the University of Navarre.

The aim of this work was to investigate the effects of hot water temperature (88, 92, 96 and 98º C), water pressure (7, 9 and 11atm), grinding grade (coarse, fine and very fine) and coffee/water ratio (6.5, 7.5 and 8.5g/40mL) on the quality of three type of EC (Arabica, Robusta Natural Blend and Robusta Torrefacto Blend) in order to select the optimal conditions.

For the selection of the conditions, physicochemical analysis and sensorial analysis by a judges panel and volatile profile were carried out. For preparation of Espresso Coffees an experimental prototype machine was used.

The technological conditions selected were 92º C and 9 atm. Moreover, it was observed that for preparation of EC with torrefacto roast was required a grinding grade coarser and lower coffee/water ratio than in natural roast.

Moreover, recently antioxidant properties have been observed in the coffee brew. For this reason, the antioxidant and pro-oxidant activity of coffee was study. The arabica variety had lower antioxidant capacity than robusta and the highest values of antioxidant capacity were obtained with torrefacto roast. On the other hand, a study with coffee model systems was carried out in order to know which compounds (caffeic acid, glycine and sucrose) have a key role on the antioxidant capacity of coffee.