Diterpenes in espresso coffee: impact of preparation parameters

Abstract

The aim of the present study was to evaluate the effect of preparation conditions of espresso coffee (EC) on the diterpenes profile. ECs were prepared from roasted and ground (R&G) Arabica coffee and analyzed for the content of cafestol and kahweol by liquid-liquid extraction followed by HPLC-DAD, as well as their lipid content. The main variables in the present study were: the water quantity, the amount of coffee, the particle size, the percolation time, the water temperature and pressure.Average cafestol, kahweol and lipid content of R&G Arabica coffee were 467 ± 20 mg/100 g, 638 ± 33 mg/100 g, and 15.1 ± 0.1 g/100 g, respectively. Although all parameters influenced the diterpenes content of ECs (21 samples), the particle size and water quantity were the most significant ones. It was possible to reduce the total diterpenes from 58.8 ± 0.7 mg/L (2.3 mg/40 mL) to 30.7 ± 0.8 mg/L (1.2 mg/40 mL) by varying the brewing conditions. The extraction yield of diterpenes and lipids were in the range of 1.5-2.5% and 7.0-9.0%, respectively. Regarding total cafestol and kahweol, very fine particles seem to be more desirable for the production of highly concentrated brew (2.3 mg/40 mL) with cafestol and kahweol extraction yields of 2.8 and 2.9%, respectively, than other studied ECs. On the other hand, samples brewed at 70 ºC exhibited lower diterpenes content (1.2 mg/40 mL) and diterpenes extraction efficiency (1.4%) with respect to all other considered parameters. This study clearly shows that parameters for coffee brew preparation may be changed to modify the diterpenes content of ECs according to the desired purpose.Keywords Espresso coffee, Brewing, Diterpenes, Roasted coffee beans IntroductionCoffee is a globally consumed beverage and can be prepared in different ways. One of the common coffee brewing techniques is the Italian "Espresso" which are consumed over than 50 million cups per days [1]. Espresso coffee (EC) is an intense beverage with special aroma made for immediate consumption [2]. For the preparation of espresso coffee, a limited amount of hot water (90±5 °C), under pressure (9±2 bar), passes through a compressed finely roasted and ground coffee (R&G, 6.5±1.5 g) in a short period of time (30±5 s) and produces a brew (15-50 mL) with strong taste and flavor topped with crema (dense foam layer) [1,

How the variance of some extraction variables may affect the quality of espresso coffees served in coffee shops

“…The coffee ground was normally distributed with the lowest weight fractions for dimensions greater than 600 µm and lower than 180 µm, while the majority of the coffee ground was in the range of 250–400 µm, with mass fraction values between 32 ± 4.8% and 47.14 ± 14.14%. According to our results, Moeenfard et al reported a normal distribution but, in other cases, by using a laser diffraction system, a particle size distribution with a bimodal shape was observed showing a mass fraction of ∼2% for particles having sizes in the range of 50–100 µm . This difference is caused by the tendency of the finest particles (<100 µm) to aggregate into larger particles which cannot be resolved when using the sieve‐based method.…”

The Occurrence of Cafestol and Kahweol Diterpenes in Different Coffee Brews

“…For espresso, moka and French press coffee, the soluble lipids and solid material easily pass through the metal filter such as the diterpenes retained (RATNAYAKE et al, 1993). For espresso coffee, the diterpene levels are dependent on steam pressure (8 -12 bar) and coffee-to-water ratio (GROSS; JACCAUD; HUGGETT, 1997;MOEENFARD et al, 2015a;RATNAYAKE et al, 1993;SILVA et al, 2012). The pressure forces the oil inside the cells to migrate to the surface of coffee particles, where they are carried out by the hot water (MESTDAGH; GLABASNIA; GIULIANO, 2017).…”

“…Recently, Portuguese researchers from University of Porto (UP) approached the subject in four studies after noticing some gaps in the literature. The first one, by Moeenfard et al (2015a), studied the impact of espresso preparation parameters on diterpene profiles, using HPLC-DAD. The parameters evaluated were: water and coffee powder amount, particle size, percolation time, water temperature and pressure.…”

Liquid chromatography with diode array detection combined with spectral deconvolution for the analysis of some diterpene esters in Arabica coffee brew

“…Then, 2.5 mL of coffee brew was transferred to polyethylene tubes and left to cool for some minutes and subjected to LLE. Extraction of diterpene esters was performed in duplicate according to the developed and validated methodology described previously by Moeenfard et al . Briefly, coffee brews were extracted directly using 5 mL of diethyl ether.…”