Pu-erh tea unique aroma: Volatile components, evaluation methods and metabolic mechanism of key odor-active compounds

Chao, Wang; Li, Juan; Wu, Xuejiao; Zhang, Ya; He, Zhongrong; Zhang, Yin; Zhang, Xingmin; Qin, Li; Huang, Jianan; Z, Liu

doi:10.1016/j.tifs.2022.03.031

Cited by 65 publications

(49 citation statements)

References 54 publications

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“…A positive correlation means that increasing the concentration of the specific volatile compound increases the ΔR of the sensor as well. This phenomenon has been observed in eight compounds (three alkanes, one ester, two alcohols, one aldehyde and one ketone) with their characteristic scent 2,6,7-trimethyl decane (acetic, moldy) [ 52 ], dodecane (dry musk, essential oil of zingiber officinale) [ 96 ], 4,6-dimethyl- dodecane (floral, present in sweet violet Viola odorata) [ 52 ], acetic acid, hexyl ester (fruity, green, apple, banana, sweet) [ 97 ], 1-pentanol (fusel, fermented bready, cereal and fruity) [ 53 ], 3,7-dimethyl-3-octanol (clean, fresh, floral tea, citrus and herbal) [ 53 ], nonanal (aldehydic, citrus, cucumber, melon, rindy potato) [ 97 ] 5-ethyl-4-methyl 3-heptanone, (fruity, citrus) [ 53 ]. On the contrary, a negative correlation means that with the increase in the concentration for the different compounds, a decrease in the ΔR of the sensor response is observed.…”

Section: Resultsmentioning

confidence: 99%

Volatile Olfactory Profiles of Umbrian Extra Virgin Olive Oils and Their Discrimination through MOX Chemical Sensors

Mariotti

Núñez-Carmona

Genzardi

et al. 2022

Sensors

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Extra virgin olive oil (EVOO) is the best vegetable oil worldwide but, at the same time, is one of the product victims of fraud in the agri-food sector, and the differences about quality within the extra-virgin olive oil category are often missed. Several scientific techniques were applied in order to guarantee the authenticity and quality of this EVOO. In the present study, the volatile compounds (VOCs) by gas chromatography–mass spectrometry with solid-phase micro-extraction detection (GC–MS SPME), organoleptic analysis by the official Slow Food panel and the detection by a Small Sensor System (S3) were applied. Ten EVOOs from Umbria, a central Italian region, were selected from the 2021 Slow Food Italian extra virgin olive oil official guide, which includes hundreds of high-quality olive oils. The results demonstrated the possibility to discriminate the ten EVOOs, even if they belong to the same Italian region, by all three techniques. The result of GC–MS SPME detection was comparable at the discrimination level to the organoleptic test with few exceptions, while the S3 was able to better separate some EVOOs, which were not discriminated perfectly by the other two methods. The correlation analysis performed among and between the three methodologies allowed us to identify 388 strong associations with a p value less than 0.05. This study has highlighted how much the mix of VOCs was different even among few and localized EVOOs. The correlation with the sensor detection, which is faster and chipper compared to the other two techniques, elucidated the similarities and discrepancies between the applied methods.

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Section: Resultsmentioning

confidence: 99%

Volatile Olfactory Profiles of Umbrian Extra Virgin Olive Oils and Their Discrimination through MOX Chemical Sensors

Mariotti

Núñez-Carmona

Genzardi

et al. 2022

Sensors

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“…Alcohols were considered to be the main contributors in the formation of the characteristic aroma of dark tea (Lv et al, 2013). As an important class of volatile compounds, alcohols often have special scents, including 'floral' , 'sweet' , and 'woody' odors (Wang et al, 2022a). Among these identified volatile compounds, linalool was found to be the most abundant in tea samples, with a mean content of 1.03 μg/g, and it contributes to a flower and lavender aroma.…”

Section: Discussionmentioning

confidence: 99%

“…The primary processes in dark tea production involves fixing, rolling, pile-fermentation and drying (Yan et al, 2021). In the pile-fermentation process, artificially inoculated or naturally bred microorganisms secrete various extracellular enzymes, such as polyphenol oxidase, protease, pectinase, cellulase, and so on (Wang et al, 2022a). These enzymes promote a series of chemical reaction, such as oxidation and condensation under hot and humid conditions.…”

Section: Introductionmentioning

confidence: 99%

Aroma effects of critical volatile compounds during thermophilic bacteria pile-fermentation in dark tea using gas chromatography mass spectrometry and odor activity value

et al. 2022

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Thermophilic bacteria play an important role in aroma formation during pile-fermentation process of dark tea. With the aim to reveal the impact of thermophilic bacteria on volatile compounds in dark tea, Bacillus licheniformis (thermophilic bacteria) were inoculated into sun-dried green tea for spontaneous fermentation. In this study, headspace solid phase microextraction combined to gas chromatography mass spectrometry (HS-SPME-GC-MS), odor activity value (OAV), principal component analysis (PCA) and orthogonal partial least squares discrimination analysis (OPLS-DA) were employed to investigated the characteristics of volatile compounds during thermophilic bacteria pile-fermentation. According to HS-SPME-GC-MS, a total of 64 volatile compounds were identified. PCA revealed that tea samples could be clearly discriminated from each other. Furthermore, sulcatone, hexanoic acid, linalool, 2-methyl-trans-decalin, myrtenal, and α-ionone were found to play an important role in discrimination of tea samples, based on OPLS-DA. In addition, the OAV could effectively characterize the aroma contribution of volatile compounds during thermophilic bacteria pile-fermentation, and (Z)-linalool oxide (furanoid), α-ionone, (E)-2-nonenal, and linalool were the critical volatile compounds of aroma quality in dark tea. This study provides insight into volatile compounds characteristics during thermophilic bacteria pile-fermentation in dark tea.

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“…Many studies have extensively explored the aroma of Pu-Erh tea through sensory evaluation, instrumental analysis, odor activity values (OAVs), and aroma recombination. The activities of microorganisms are the key to the formation of Pu-Erh tea aroma. , These studies evaluated the effects of post-fermentation methods and different microbial strains on the volatile compounds of Pu-Erh tea. − However, there are no studies yet available on chiral compounds in RAPT and RIPT. The composition ratio and content of enantiomers of chiral compounds are often used as the basis for judging the adulteration of tea and alcoholic beverages .…”

Section: Introductionmentioning

confidence: 99%

“…The activities of microorganisms are the key to the formation of Pu-Erh tea aroma. 5,6 These studies evaluated the effects of postfermentation methods and different microbial strains on the volatile compounds of Pu-Erh tea. 7−11 However, there are no studies yet available on chiral compounds in RAPT and RIPT.…”

Section: ■ Introductionmentioning

confidence: 99%

Aromatic Profiles and Enantiomeric Distributions of Chiral Volatile Compounds in Pu-Erh Tea

Zhu

Niu

Xiao

2022

J. Agric. Food Chem.

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Pu-Erh tea, as a typical post-fermented tea, can be divided into raw Pu-Erh tea (RAPT) and ripened Pu-Erh tea (RIPT) according to the processing technology. It is famous for its unique aroma after aging. Although previous research on the aroma characteristics of Pu-Erh tea mostly focused on the aroma compounds, little research on chiral compounds in RAPT and RIPT has been performed. Therefore, the current work aims to explore the aroma characteristics of Pu-Erh tea from the perspective of enantiomers of chiral compounds. A total of 15 enantiomers were determined in this study, among which (R)-(−)-2,2,6-trimethylcyclohexanone, (R)-(−)-linalool, (S)-(+)-linalool, (R)-(+)-δ-octanolactone, (R)-(+)-γ-nonanolactone, (2R,5R)-(+)-theaspirone A, and (R)-(−)-dihydroactinidiolide were identified as enantiomeric compounds that play an important role in the aroma of RAPT and RIPT. Furthermore, (2S,5R)-trans-linalool oxide and (R)-(+)-α-terpineol were important contributors to the aroma profile of RAPT, while (S)-(+)-2-methylbutanal, (S)-(−)-limonene, S-(−)-α-terpineol, and (1R,2R)-(−)-methyl jasmonate contributed to the characteristic aroma of RIPT. The addition of these enantiomeric compounds brings the aroma closer to that of the original tea sample. In addition, the analysis of chiral enantiomers of linalool, limonene, theaspirone A, and γ-nonanolactone can provide guidance for the quality and flavor control of Pu-Erh tea aroma.

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Pu-erh tea unique aroma: Volatile components, evaluation methods and metabolic mechanism of key odor-active compounds

Cited by 65 publications

References 54 publications

Volatile Olfactory Profiles of Umbrian Extra Virgin Olive Oils and Their Discrimination through MOX Chemical Sensors

Volatile Olfactory Profiles of Umbrian Extra Virgin Olive Oils and Their Discrimination through MOX Chemical Sensors

Aroma effects of critical volatile compounds during thermophilic bacteria pile-fermentation in dark tea using gas chromatography mass spectrometry and odor activity value

Aromatic Profiles and Enantiomeric Distributions of Chiral Volatile Compounds in Pu-Erh Tea

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