Profiles of volatile compounds and sensory analysis of three blends of coffee: influence of different proportions of Arabica and Robusta and influence of roasting coffee with sugar

Abstract

One hundred and forty-six volatile compounds were identi®ed and quanti®ed using a static headspace sampler in three blends of coffee: Arabica/Robusta 80:20 (A80:R20) natural roasted coffee, Arabica/Robusta 20:80 (A20:R80) natural roasted coffee and Arabica/Robusta 20:80 with 50% of Robusta coffee roasted with sugar (A20:R80 50% Torrefacto). The different proportion of Arabica and Robusta coffee in the blend A80:R20 versus A20:R80 in¯uenced the amounts of 20 chemical families of volatile compounds. and terpenes were present in higher quantities in the sample containing 80% of Arabica coffee, whereas sulphur compounds were more abundant in the coffee with 80% of Robusta. Sensory differences were also found between the two blends of coffee in the burnt, caramel, nutty, earthy and roasty notes. Torrefacto coffee, widely consumed in Spain, is obtained by roasting coffee with sugar. Higher quantities of ketones, alcohols, pyrazines, furans, pyridines, alkanes, phenolic compounds, pyranones and terpenes were found in the blend A20:R80 50% Torrefacto coffee versus A20:R80 natural roasted coffee. These differences in the volatile fraction were perceived by our panellists in the intensities of the nutty, roasty, earthy, burnt and caramel notes.

Contribution of volatile compounds to the antioxidant capacity of coffee

“…Aldehydes and esters are responsible for fruity and malty coffee flavor notes, whereas diketones contribute to the buttery aroma, and furans are considered to be responsible for the typical roasted coffee aroma (Semmelroch & Grosch, 1995;Maeztu et al, 2001;Flament, 2001). Similar results were reported in previous works of our group when volatile compounds of Arabica coffee were compared with those found in Arabica-Robusta coffee blends roasted by conventional or torrefacto techniques (Sanz, Maeztu, Zapelena, Bello, & Cid, 2002;Lopez-Galilea, Andriot, de Peña, Cid, & Guichard, 2008a). In contrast, chromatographic areas of pyrazines and pyridines, and in less proportion thiazoles, were higher in Robusta coffee.…”

“…Pyrazines are responsible for roasted, earthy, musty and woody flavor notes characteristic of Robusta coffee (Blank, Sen & Grosch, 1991;Semmelroch & Grosch, 1995;Lopez-Galilea, Fournier, Cid, & Guichard, 2006) and pyridines contribute to smoky aroma (Flament, 2001). Also, low molecular weight phenolic compounds, and mainly 2-methoxyphenol (guaiacol) that is a key odorant responsible of phenolic and burnt aroma (Semmelroch & Grosch, 1995;Sanz et al, 2002;Lopez-Galilea et al, 2006), were only detected in Robusta coffee samples at low levels but not in Arabica. Similar results were found by other authors in conventional roasted Arabica and Robusta coffee (Semmelroch & Grosch, 1995;Maeztu et al, 2001;Lopez-Galilea et al, 2008b) and coffee brews (Maeztu et al, 2001).…”

Determination of the Elemental Composition of Coffee Using Instrumental Methods

“…Color and flavor characteristics are important to find the best degree of roasting green beans (Belitz et al 2009). For the evaluation of the quality of coffee infusions, the flavor of prepared beverages is commonly described under standardized conditions (Sanz et al 2002). All individual notes of each sample are collected and its unique profile is assessed, however, it should be noted that opinions of qualified coffee testers on coffee taste and aroma can be subjective (Krivan et al 1993;Anderson and Smith 2002).…”

HS-SPME/GC/MS profiles of convectively and microwave roasted Ivory Coast Robusta coffee brews

“…One of the principal technological processes is roasting that gives rise to the formation of the characteristic flavour and taste of coffee brews ( Yeretzian et al 2002). The aroma of roasted coffee depends on the variety of coffee, agricultural factors, post-harvest treatment, and the conditions of storage and roasting (Hashim & Chaveron 1996;Semmelroch & Grosch 1996;Sanz et al 2002;Mondello et al 2005). The flavour of coffee brews is different from the aroma of roasted coffee beans.…”

“…It is one of the reasons for the higher price of Arabica coffee. Commercial coffee blends contain different proportions of Robusta and Arabica as a compromise between the taste and the price (Sanz et al 2002). An improvement on the sensory properties of Robusta coffee brews, mainly through modifications of roasting and brewing conditions, has recently been the subject of extensive studies.…”