Abstract:This research aimed to explore the dynamic changes of aroma compounds composition and mass fraction of coffee brews at different stages of extraction process. The roasted Guatemalan coffee beans were selected to prepare coffee brews under a continuous constant pressure 900 kPa extraction. The HS-SPME-GC/MS method was used to study the mass fraction of aroma compounds in coffee brews. The results showed that the constant pressure extraction process of key volatile aroma compounds conformed to the Power Law equation, and the polarity was the key factor that determined the dynamic extraction rate. In the initial stage of extraction, the extraction rate constant of strong polarity substances such as 2-methylpyrazine was 7 to 35 times that of β-damascone with weak polarity. At the end of extraction, the total mass fraction of weak polarity substances increased from 20% to 30%, and the aroma balance changed. During the continuous extraction process, the odor activity value of key compounds in light and medium roasted coffee decreased faster than that in dark roasted coffee. Based on the experimental data, combined with and concerned about the Golden cup extraction regulations formulated by the Specialty Coffee Association, the study proposed that in order to obtain a cup of coffee with a better balance of taste and aroma, the cup extraction could be controlled to 30~40 g of 17 g coffee powder for light and medium roasted coffee, and 40~50 g of 17 g coffee powder for dark roasted coffee.
