Characterization of the aroma-active compounds in Xiaokeng green tea by three pretreatment methods combined with gas chromatography−olfactometry (GC-O)

• Published in: Food research international Vol. 187; p. 114359
• Main Authors: Gan, Shiya, Chen, Yingqi, Zhao, Lei, Zhao, Xiaoyi, Qiu, Tong, Zhai, Xiaoting, Dai, Qianying
• Format: Journal Article
• Language: English
• Published: Canada Elsevier Ltd 01.07.2024
• Subjects: Aroma attribute; Aroma-active compound; Camellia sinensis - chemistry; Gas Chromatography-Mass Spectrometry; Humans; Network analysis; Odorants - analysis; Olfactometry; Pretreatment method; Relative odor activity value (rOAV); Solid Phase Extraction - methods; Solid Phase Microextraction - methods; Tea - chemistry; Volatile Organic Compounds - analysis; Xiaokeng green tea; GC–MS; Xiaokeng green tea; Aroma attribute; Relative odor activity value (rOAV); SBSE; rOAV; AI; Aroma-active compound; XKGT; SE-SPE; Pretreatment method; QDA; HS-SPME; Network analysis; GC-O
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2024.114359

[Display omitted] •Soybean-like, fresh, and corn-like were the major sensory properties.•HS-SPME, SBSE, and SE-SPE with GC–MS were used to determine volatiles.•(E, Z)-2,6-Nonadienal, and (E)-β-ionone were clarified as key odorants.•(E, Z)-2,6-Nonadienal, nonanal and octanal were responsible for fresh aroma.•Indole was involved in chestnut-like and soybean-like notes. Chinese Xiaokeng green tea (XKGT) possesses elegant and fascinating aroma characteristics, but its key odorants are still unknown. In this study, 124 volatile compounds in the XKGT infusion were identified by headspace-solid phase microextraction (HS-SPME), stir bar sorptive extraction (SBSE), and solvent extraction-solid phase extraction (SE-SPE) combined with gas chromatography-mass spectrometry (GC–MS). Comparing these three pretreatments, we found HS-SPME was more efficient for headspace compounds while SE-SPE was more efficient for volatiles with higher boiling points. Furthermore, SBSE showed more sensitive to capture ketones then was effective to the application of pretreatment of aroma analysis in green tea. The aroma intensities (AIs) were further identified by gas chromatography–olfactometry (GC-O). According to the AI and relative odor activity value (rOAV), 27 compounds were identified as aroma-active compounds. Quantitative descriptive analysis (QDA) showed that the characteristic aroma attributes of XKGT were chestnut-like, corn-like, fresh, and so on. The results of network analysis showed that (E, Z)-2,6-nonadienal, nonanal, octanal and nerolidol were responsible for the fresh aroma. Similarly, dimethyl sulfide, (E, E)-2,4-heptadienal, (E)-2-octenal and β-cyclocitral contributed to the corn-like aroma. Furthermore, indole was responsible for the chestnut-like and soybean-like aroma. This study contributes to a better understanding of the molecular mechanism of the aroma characteristics of XKGT.