Application of SPME‐GC‐TOFMS, E‐nose, and sensory evaluation to investigate the flavor characteristics of Chinese Yunnan coffee at three different conditions (beans, ground powder, and brewed coffee)

Abstract

SPME‐GC‐TOFMS, E‐nose, and sensory evaluation were used to explore the volatile organic compounds (VOCs) in four Chinese Yunnan coffee at three conditions (beans, ground powder, and brewed coffee). VOCs were detected by GC‐TOFMS and compared the difference between all samples, depending on the VOCs in the coffee sample. The E‐nose was used for rapid detection to differentiate the sample. The two results are analyzed by principal component analysis (PCA). Quantitative description analysis (QDA) was used to evaluate the flavor profiles of coffee samples. The results shown that GC‐TOFMS detected 412, 498, and 294 VOCs in roasted, ground powder, and brewed coffee, respectively. The PCA of SPME‐GC‐TOFMS results shown that Nankang coffee was mainly related to ketone compounds; the aroma of Hongguang coffee was determined by dimethyl disulfide and acetic acid; pyrazine and ketone compounds were important to Hainan coffee; ketone and ester compounds were dominated in Xinghuan coffee. The results of E‐nose shown that the first two principal components (PCs) accounted for 97.3%, 92.5%, and 93.8% of variances in roasted, ground powder, and brewed coffee, respectively. The different brands of coffee samples at the same condition shown separated locations on the PCA results of E‐nose. Sensory evaluation shown the special flavor of coffee samples, Nankang coffee with a bake flavor, Hongguang coffee had chocolate and nutty flavors, Hainan coffee had the caramel‐like aroma, and the aroma Xinghuan coffee was sweet. This study could provide a better understanding of Chinese coffee produced in Yunnan province.

Review on factors affecting coffee volatiles: from seed to cup

“…The intrinsic quality of a particular coffee arises from the specific characteristics of its region of origin 32 . For example, Brazilian coffee is mildly bitter, light and warm, with an unrestrained tropical palate, and is an excellent base for blended coffees; Columbian coffee is round, sour and sweet with a strong perfume, and thick tasting; arabica coffee from the Yunnan province of China is strong but not bitter, fragrant but not strong, with slight acidity 33‐35 . The biggest coffee‐growing country in the world is Brazil, followed by Vietnam, Indonesia, Columbia, Honduras, Ethiopia, Peru and Guatemala (Fig.…”

The study of citrus‐derived flavonoids as effective bitter taste inhibitors

“…The bitter inhibition rate ( BIR ) was used as an index to evaluate the bitter inhibition effect of citrus flavonoids, 27 with positive BIR values indicating inhibitory and the negative values indicating enhancement: To describe the change in intensity of bitterness, sweetness, as well as other relevant attributes of citrus fruit wine, quantitative description analysis (QDA) was conducted. In an introductory discussion, the attributes of citrus fruit wine evaluated were selected together with the panel, focusing on attributes describing differences in taste among the citrus fruit wine samples 28,29 . The attributes and intensity score are shown in the Supporting information (Table S2).…”

Insights on Single-Dose Espresso Coffee Capsules’ Volatile Profile: From Ground Powder Volatiles to Prediction of Espresso Brew Aroma Properties

“…To determine the volatile profile of single-dose espresso capsule coffee-based blends, a range of eight commercial samples was studied by HS-SPME/GC × GC-ToFMS, differing in the labeled blend intensity To determine the volatile profile of single-dose espresso capsule coffee-based blends, a range of eight commercial samples was studied by HS-SPME/GC × GC-ToFMS, differing in the labeled blend intensity (Blends 1 to 3, intensity 1 < 2 < 3) and origins (Blend 4, Jamaica, Blend 5, Tanzania, and Blend 6, Ethiopia), a decaffeinated blend (Blend Dec), and a blend supplemented (Blend Sup) with natural plant extracts of guaraná (Paullinia cupana) and ginseng (Panax ginseng). A total of 390 volatile compounds (ranging from 381 to 386 in coffee powders and 380 to 387 in espresso brews), distributed over 17 chemical families, including acids (4), alcohols (12), aldehydes (26), esters (40), furan compounds (63), hydrocarbons (25), ketones (60), volatile phenols (5), oxazoles (9), pyrazines (36), pyridines (9), pyrroles (11), sulfur compounds (12), terpenic compounds (29), norisoprenoids (6), thiazoles (19), and thiophene compounds (24), was determined in the assayed single-dose coffee capsule blends (Table 1, chromatograms in Figure S1 and chromatographic details in Table S1). These chemical families were already reported in different coffee samples [5,6,9,21] commonly associated with industrial coffee production during fermentation (acids, alcohols, aldehydes, and esters) and roasting processes (furan compounds, ketones, pyrazines, pyridines, and pyrroles), as well as plant varietal compounds, thus they were already present in the green coffee beans (terpenic compounds and norisoprenoids) [19][20][21].…”

“…Considering the 390 compounds putatively identified (Figure 2c), the furans family accounted for the highest number of compounds (63), although with a quite lower relative dominance (16.2%) related to their GC × GC peak areas. Indeed, some families had a considerable number of compounds, although this did not correspond to a high relative contribution in GC × GC peak area, such as terpenic compounds (29 compounds-7.4%, but 0.6-2.0% peak area in powders and 0.2-0.9% in brews), thiophene compounds (24 compounds, <2.2% of peak area) or thiazoles (19 compounds, <1.1% of peak area).…”

“…The aqueous nature of the extraction process hinders the passage of coffee powder hydrophobic compounds to the brew. Moreover, the non-or low-water soluble volatile compounds tend to migrate in a higher extent in the brew to the headspace and are perceived by the consumer [63]. As a consequence, only a few compounds relevant to the aroma of the brews are extracted from the solid matrix and perceived in the brew in the same proportion.…”