Foamability, Foam Stability, and Chemical Composition of Espresso Coffee As Affected by the Degree of Roast

Abstract

Two coffees of different botanical and geographical origins were used: Brazil coffee (dry-processed Arabica) and Uganda coffee (dry-processed robusta). The samples were roasted, and the foamability and foam stability of the espresso coffee were determined as a function of the degree of roast. Espresso coffees were characterized with regard to the amount of total solids, pH, fat, protein, and carbohydrate. The polymeric carbohydrates were precipitated with ethanol solutions (55 and 75% ethanol fractions), and the component monosaccharides were quantified by gas−liquid chromatography. A principal component analysis was applied to the chemical variables. This study showed that foamability of the espresso coffee increases with degree of roast and depends on the amount of protein in the infusion. Foamability as a function of the degree of roast does not differ significantly for the two coffees. Foam stability of espresso coffee as a function of degree of roast is related to the amount of galactomannan and arabinogalactan present and seems to be independent of the origin of the coffee despite the coffees having shown a different degree of roast for maximum foam stability. The degree of roast as a technological parameter does not allow an espresso coffee with maximum foamability and foam stability to be obtained at the same time. Keywords: Espresso coffee; degree of roast; foamability; foam stability; galactomannan; arabinogalactan; multivariate analysis; principal component analysis

Diterpenes in espresso coffee: impact of preparation parameters

“…Final quality of EC may vary from one cup to another one, depending on different factors such as coffee species, roasting degree [4], water quality [5], personal preferences [1], as well as the extraction device [6]. These factors may influence the coffee brew composition which resulted in ECs with different physicochemical and sensory properties.…”

Optimization of espresso machine parameters through the analysis of coffee odorants by HS-SPME–GC/MS

“…In spite of its worldwide popularity, the conditions for optimal espresso preparation have not yet been defined in detail. In fact, as noted by Petracco (1989) and Illy and Viani (1995), there is a lack of standardization in the weight of roasted ground coffee used, the beverage volume, and the extraction conditions (water pressure and temperature), parameters likely to influence the EC aroma (Nunes, Coimbra, Duarte, & Delgadillo, 1997). The composition of the volatile fraction of roasted and brewed coffee has been studied for years, and several hundred compounds have been reported as constituents of coffee aroma (Holscher & Steinhart, 1992;Maeztu, Sanz, et al, 2001;Ramos, Valero, & Iba, 1998;Sanz, Ansorena, Bello, & Cid, 2001;Sanz, Maeztu, Zapelena, Bello, & Cid, 2003).…”

Immunostimulatory properties of coffee mannans

“…Besides the important functional properties that the polysaccharides confer to the coffee infusions, they are involved in the retention of coffee volatile substances and contribute to the brew viscosity and, thus, to the , body' of the drink, i. e., the creamy sensation perceived in the mouth [4]. They are also involved in the foam stability of espresso coffee, an important quality attribute of this coffee brew [5,6]. Recently, they have been shown to have beneficial biological activities, namely, undergoing rapid fermentation in the human colon and thereby contributing to the physiological effects generally associated with fibre fermentation [7 -9].…”