The Chemistry of Green and Roasted Coffee by Selectable 1D/2D Gas Chromatography Mass Spectrometry with Spectral Deconvolution

Abstract

Gas chromatography/mass spectrometry (GC/MS) is a long-standing technique for the analysis of volatile organic compounds (VOCs). When coupled with the Ion Analytics software, GC/MS provides unmatched selectivity in the analysis of complex mixtures and it reduces the reliance on high-resolution chromatography to obtain clean mass spectra. Here, we present an application of spectral deconvolution, with mass spectral subtraction, to identify a wide array of VOCs in green and roasted coffees. Automated sequential, two-dimensional GC-GC/MS of a roasted coffee sample produced the retention index and spectrum of 750 compounds. These initial analytes served as targets for subsequent coffee analysis by GC/MS. The workflow resulted in the quantitation of 511 compounds detected in two different green and roasted coffees. Of these, over 100 compounds serve as candidate differentiators of coffee quality, AAA vs. AA, as designated by the Coopedota cooperative in Costa Rica. Of these, 72 compounds survive the roasting process and can be used to discriminate green coffee quality after roasting.

A new Coffee Brewing Control Chart relating sensory properties and consumer liking to brew strength, extraction yield, and brew ratio

“…The enjoyment of coffee worldwide is driven primarily by its sensory quality (Samoggia & Riedel, 2018), which in turn depends on the variety, origin, terroir, postharvest processing, roasting, and brewing of the coffee through a complex mixture of flavor compounds that include carbohydrates, acids, lipids, proteins, antioxidants, and volatile aroma compounds (Clarke & Macrae, 1985; Frost et al., 2022; Seninde & Chambers, 2020; Sunarharum et al., 2014; Yeager et al., 2021). In particular, the rise of “specialty” coffee has driven expanding research into coffee flavor and brewing in the past decade (Allhoff et al., 2011; Mestdagh et al., 2017; Sunarharum et al., 2014).…”

Metabolic Profiling, Antioxidant Activity, and Alpha-Glucosidase Inhibitory Activity of the Roasted Beans of Luwak (Civet) Coffee

“…Consequently, the roasting process alters the metabolites of green coffee beans. Identification of the metabolites of roasted coffee beans using the metabolomic approach had been performed using a variety of instruments, including IR, GC–MS, LC–MS, and 1 H NMR . According to the metabolomic results, each roasted coffee has a distinct profile of metabolites.…”