Integrating GC-TOF-MS, ROAV and Chemometrics to Understand the Flavour Characteristics of arabica Coffee Varieties in Yunnan

The Yunnan Province is the primary coffee-growing region in China. In this study, the flavour components of seven arabica coffee varieties in Yunnan were detected by headspace solid-phase microextraction-gas chromatography time-of-flight mass spectrometry (HS-SPME-GC-TOF-MS) and a total of 178 volatile components were annotated. There were 31 aroma compounds with 1 ≤ rOAV < 100 and 41 aroma compounds with rOAV ≥ 100. According to the aroma characteristics, defined by the relative odour activity value (rOAV) ≥ 1, the arabica coffee in Yunnan primarily exhibits fruit, sour, nut and floral aromas. Particularly, the isobutyl acetate and n-butyric acid found in Bourbon varieties enhance its fruit and sour aromas. In contrast, Geisha has a prominent floral aroma. Additionally, the 2,3-dimethyl-5-methylpyrazine present only in Catuai significantly contributes to its nutty aroma. The present results provide a valuable theoretical basis for understanding the aroma characteristics of different varieties of arabica coffee and their key underlying components.