Abstract
(1) Background: Recently, a new espresso extraction method, Caffè Firenze, has been developed, which uses gas at operating pressures of 20 bar to obtain abundant, persistent foam. The experiment aimed to evaluate the effect of using six gases (air, argon, nitrogen, carbon dioxide, carbon/nitrogen mix, and nitrous oxide) on the foam and liquid coffee. (2) Methods: Foam volume, persistence, sugar retention time, color, and rheological properties were measured. Volatile organic compounds were also evaluated. Analyses were also carried out on the liquid coffee to determine caffeine and chlorogenic acid concentrations. (3) Results: The analysis of variance revealed significant differences between the gases for all parameters. Multivariate analysis identified three groups of gases: the first comprised air, N2, and Ar; the second CO2 and N2O; and the third comprised samples extracted with CO2/N2 mix. (4) Conclusions: The choice of gas significantly influences the drink’s chemical-physical characteristics and is fundamental for product diversification.
Highlights
Coffee is one of the world’s principal commodities
Coffee foam can be defined as a coarse biphasic system, made up of the liquid phase of the beverage, and small, spherical gas globules, each of which is surrounded by a lamella that hosts biopolymers
The second part characterizes the liquid part of the extracted samples (TDS, caffeine, and chlorogenic acids (CGAs))
Summary
Coffee is one of the world’s principal commodities. It is one of the most widely-consumed beverages as a result of its pleasant taste and aroma, not to mention its stimulant qualities.Numerous brewing apparatuses have been developed, and it is known that different brewing techniques produce beverages of different quality [1,2]. Coffee is one of the world’s principal commodities It is one of the most widely-consumed beverages as a result of its pleasant taste and aroma, not to mention its stimulant qualities. Foam is the result of the coarse dispersion of gas bubbles in a continuous liquid phase [3]. A foam layer of small bubbles is formed on top of the aqueous solution, along with dispersed fine particles and microscopic oil droplets [5]. Coffee foam can be defined as a coarse biphasic system, made up of the liquid phase of the beverage, and small, spherical gas globules, each of which is surrounded by a lamella (a liquid film) that hosts biopolymers
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