Compounds In Tea Research Articles

Effects of different over-fired drying methods on the aroma of Lu’an Guapian tea

Over-fired drying, a crucial process in the production of Lu’an Guapian (LAGP) tea, greatly enriches the tea’s aroma. In this study, the aroma compounds of LAGP tea processed through pulley charcoal drying (PCD), roller drying (RD), roller-conveyor drying (RCD), and hot air drying (HD) were analyzed using gas chromatography–mass spectrometry. A subsequent analysis of aroma extraction dilution analysis and odor activity values revealed that (E)-β-ionone, dimethyl sulfide, (E,E)-2,4-heptadienal, geraniol, linalool, benzeneacetaldehyde, coumarin, 2-ethyl-3,5-dimethyl-pyrazine, indole, hexanal, (Z)-jasmone, and (Z)-3-hexen-1-ol were the key contributors to the samples’ aroma variation. Moreover, a quantitative descriptive analysis and aroma recombination and omission experiments analysis revealed that (E)-β-ionone is the most critical contributor to the formation of floral aroma in tea processed using PCD, whereas (E,E)-2,4-heptadienal is responsible for the more pronounced fresh aroma in tea processed using HD. In addition, 2-ethyl-3,5-dimethyl-pyrazine contributes to the formation of a roasted aroma in tea processed using RD and RCD. The study results provide a theoretical basis for choosing the processing method, especially for drying, to obtain high-quality LAGP tea.

EGCG attenuates METH self-administration and reinstatement of METH seeking in mice.

Methamphetamine (METH) use disorder is a chronic, relapsing disorder and involves frequent failures of self-control of drug seeking and taking. Epigallocatechin-3-gallate (EGCG) is the most abundant polyphenolic compounds of green tea, which has shown great therapeutic effectiveness in neurological disorders. However, it is still unknown whether and how EGCG affects METH seeking behaviour. Here, we show nanostructured EGCG/ascorbic acid nanoparticles (EGCG/AA NPs) dose-dependently reduced METH self-administration (SA) under fixed-ratio 1 (FR1) and progressive ratio (PR) reinforcement schedules in mice and shifted METH dose-response curves downward. Furthermore, EGCG/AA NPs decreased drug- and cue-induced METH seeking. In addition, we found that METH SA led to a decrease in inhibitory postsynaptic currents (IPSCs) and increase in the AMPAR/NMDAR ratio and excitation/inhibition (E/I) ratio in ex vivo midbrain slices from ventral tegmental area (VTA) dopamine neurons. EGCG/AA NPs enhanced Gamma-aminobutyric acid (GABA)ergic inhibition and normalized the E/I ratio. EGCG restored the balance between excitation and inhibition in VTA dopamine neurons, which may contribute to the attenuation of METH SA. These findings indicate that EGCG is a promising pharmacotherapy for METH use disorder.

The characteristic of the key aroma-active components in white tea using GC-TOF-MS and GC-olfactometry combined with sensory-directed flavor analysis.

White tea has become more and more popular with consumers due to its health benefits and unique flavor. However, the key aroma-active compounds of white tea during the aging process are still unclear. Thus, the key aroma-active compounds of white tea during the aging process were investigated using gas chromatography-time-of-flight-mass spectrometry (GC-TOF-MS) and gas chromatography-olfactometry (GC-O) combined with sensory-directed flavor analysis. A total of 127 volatile compounds were identified from white tea samples with different aging years by GC-TOF-MS. Fifty-eight aroma-active compounds were then determined by GC-O, and 19 of them were further selected as the key aroma-active compounds based on modified frequency (MF) and odor activity value (OAV). Aroma recombination and omission testing confirmed that 1-octen-3-ol, linalool, phenethyl alcohol, geraniol, (E)-β-ionone, α-ionone, hexanal, phenylacetaldehyde, nonanal, (E, Z)-(2,6)-nonadienal, safranal, γ-nonalactone and 2-amylfuran were the common key aroma-active compounds to all samples. Cedrol, linalool oxide II and methyl salicylate were confirmed peculiar in new white tea, while β-damascenone and jasmone were peculiar in aged white tea. This work will offer support for further studies on the material basis of flavor formation of white tea. © 2023 Society of Chemical Industry.

The levels of heavy metal, acrylamide, nitrate, nitrite, N-nitrosamine compounds in brewed black tea and health risk assessment: Türkiye

The levels of heavy metal, acrylamide, nitrate, nitrite, N-nitrosamine compounds in brewed black tea and health risk assessment: Türkiye

The aroma characteristics of oolong tea are jointly determined by processing mode and tea cultivars.

This study delved into the aroma characteristics of "Qingxiang" oolong tea, analyzing six different cultivars and their processing modes. The findings showed that both cultivars and processing modes have a significant impact on the oolong tea aroma system. The study identified 18 terpenoid volatiles (VTs), 11 amino-acid-derived volatiles (AADVs), 15 fatty-acid-derived volatiles (FADVs), 3 carotenoid-derived volatiles (CDVs), and 10 other compounds in oolong tea that differentiate it from green and black tea. The turn-over stage was found to be the primary processing stage for oolong tea aroma formation. Molecular sensory analysis revealed that the "fresh" odor attribute is the basis for its aroma, while "floral and fruity" fragrances are its aroma characteristics. The perception of oolong tea as "fresh" and "floral and fruity" is influenced by the interactions of its aroma components. These findings provide a new basis for breed improvement and process enhancement in oolong tea production.

Epigallocatechin gallate effect on Interleukin-1 and MMP-9 expression as Pseudomonas aeruginosa keratitis adjuvant therapy

Link of Video Abstract: https://youtu.be/Ja9klXNlw5A Background: Keratitis Pseudomonas aeruginosa is the most frequently occurring eye infection. It is a rapidly developing condition that can lead to ocular infections (endophthalmitis) and corneal perforation resulting in vision loss. Although prompt administration of antibiotics can effectively kill the bacteria, the corneal damage caused by toxins persists. The following inflammatory process results in corneal thinning, fibrosis, and eventual perforation. Methods: This study is a literature review to support future experimental studies which will be conducted to examine the expression of IL-1b and MMP-9 on pseudomonas keratitis after administration of EGCG. Results: Interleukin-1ß is a proinflammatory cytokine secreted by various immune cells in response to acute and chronic inflammation. At the same time, matrix metalloproteinase (MMP) is a group of proteolytic enzymes involved in the pathophysiology of various ocular surface diseases. Epigallocatechin gallate (EGCG) is the major polyphenol compound in green tea, produced from the Camellia sinensis plant. Recent studies suggest that EGCG has anti-inflammatory and antioxidant effects on various cell types, including the cornea. EGCG inhibits IL-1β, which induces the activation of the NF-kB signaling pathway, which may explain the decrease in uPA expression and the reduction of collagen degradation by corneal fibroblasts. EGCG inhibits the activation of pro-MMP 9 produced by corneal fibroblasts in response to IL-1β stimulation, and this effect is mediated by the inhibition of uPA upregulation without a significant impact on pro-MMP 9 expressions. Conclusion: Epigallocatechin gallate (EGCG) in Camellia sinensis extract has the potential as an alternative adjuvant therapy for bacterial keratitis because it has antibacterial, anti-inflammatory and antioxidant effects.

Targeting fibrotic signaling pathways by EGCG as a therapeutic strategy for uterine fibroids

Fibrosis is characterized by excessive accumulation of extracellular matrix, which is a key feature of uterine fibroids. Our prior research supports the tenet that inhibition of fibrotic processes may restrict fibroid growth. Epigallocatechin gallate (EGCG), a green tea compound with powerful antioxidant properties, is an investigational drug for uterine fibroids. An early phase clinical trial showed that EGCG was effective in reducing fibroid size and its associated symptoms; however, its mechanism of action(s) has not been completely elucidated. Here, we probed effects of EGCG on key signaling pathways involved in fibroid cell fibrosis. Viability of myometrial and fibroid cells was not greatly affected by EGCG treatment (1–200 µM). Cyclin D1, a protein involved in cell cycle progression, was increased in fibroid cells and was significantly reduced by EGCG. EGCG treatment significantly reduced mRNA or protein levels of key fibrotic proteins, including fibronectin (FN1), collagen (COL1A1), plasminogen activator inhibitor-1 (PAI-1), connective tissue growth factor (CTGF), and actin alpha 2, smooth muscle (ACTA2) in fibroid cells, suggesting antifibrotic effects. EGCG treatment altered the activation of YAP, β-catenin, JNK and AKT, but not Smad 2/3 signaling pathways involved in mediating fibrotic process. Finally, we conducted a comparative study to evaluate the ability of EGCG to regulate fibrosis with synthetic inhibitors. We observed that EGCG displayed greater efficacy than ICG-001 (β-catenin), SP600125 (JNK) and MK-2206 (AKT) inhibitors, and its effects were equivalent to verteporfin (YAP) or SB525334 (Smad) for regulating expression of key fibrotic mediators. These data indicate that EGCG exhibits anti-fibrotic effects in fibroid cells. These results provide insight into mechanisms behind the observed clinical efficacy of EGCG against uterine fibroids.

Inflammation inhibitory activity of green tea, soybean, and guava extracts during Sars-Cov-2 infection through TNF protein in cytokine storm

Coronavirus disease is caused by the pathogen severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) known as COVID-19. COVID-19 has caused the deaths of 6,541,936 people worldwide as of September 27th, 2022. SARS-CoV-2 severity is determined by a cytokine storm condition, in which the innate immune system creates an unregulated and excessive production of pro-inflammatory such IL-1, IL-6, NF Kappa B, and TNF alpha signaling molecules known as cytokines. The patient died due to respiratory organ failure and an acute complication because of the hyper-inflammation phenomenon. Green tea, soybean, and guava bioactive substances are well-known to act as anti-inflammation, and antioxidants become prospective COVID-19 illness candidates to overcome the cytokine storm. Our research aims to discover the bioactivity, bioavailability, and protein targets of green tea, soybean, and guava bioactive compounds as anti-inflammatory agents via the TNF inhibition pathway. The experiment uses in silico methods and harnesses the accessible datasets. Samples of 3D structure and SMILE identity of bioactive compounds were retrieved from the KNApSAck and Dr Duke databases. The QSAR analysis was done by WAY2DRUG web server, while the ADME prediction was performed using SWISSADME web server, following the Lipinsky rules of drugs. The target protein and protein-protein interaction were analyzed using STRING DB and Cytoscape software. Lastly, molecular docking was performed using Autodock 4.2 and visualization with BioVia Discovery Studio 2019. The identified study showed the potential of green tea, soybean, and guava’s bioactive compounds have played an important role as anti-inflammation agents through TNF inhibitor pathway.

Microbial Composition, Bioactive Compounds, Potential Benefits and Risks Associated with Kombucha: A Concise Review

Kombucha is a fermented tea beverage containing bioactive compounds from tea and vital compounds such as acetic acid, D-saccharic acid-1,4-lactone, and glucuronic and gluconic acids produced from the metabolic activities of bacteria and yeasts, which benefit human health. Kombucha contains a symbiotic culture of bacteria and yeast (SCOBY), which actively ferments sugar. Kombucha microbial compositions vary due to environmental conditions and the starter culture. Saccharomyces sp., Schizosaccharomyces pombe, Schizosaccharomyces sp., and Brettanomyces sp. (yeasts) and Acetobacter aceti, Komagataeibacter xylinum (formerly known as Gluconacetobacter xylinum), Gluconobacter oxydans, and Acetobacter pasteurianus (acetic acid-producing bacteria) are commonly found in kombucha. This review focused on the microbial compositions of kombucha and their functionality. Aspects discussed include: (i). developments in kombucha, (ii). microbial compositions of kombucha, (ii). microbial production of kombucha cellulose, (iv). factors influencing kombucha microbial compositions, (v). tea type and kombucha bioactive compounds, (vi). kombucha health benefits, and (v). potential risk factors of kombucha consumption. Current gaps, recommendations, and prospects were also discussed. Kombucha production using rooibos as the tea base is recommended, as rooibos is caffeine-free. Upcycling kombucha wastes, mainly SCOBY, for producing cellulose filters, improving food flavors and as a substrate in food fermentations is touched on.

A rapid aroma quantification method: Colorimetric sensor-coupled multidimensional spectroscopy applied to black tea aroma

Aroma affects the quality of black tea, and the rapid evaluation of aroma quality is the key to realize the intelligent processing of black tea. A simple colorimetric sensor array coupled with a hyperspectral system was proposed for the rapid quantitative detection of key volatile organic compounds (VOCs) in black tea. Feature variables were screened based on competitive adaptive reweighted sampling (CARS). Furthermore, the performance of the models for VOCs quantitative prediction was compared. For the quantitative prediction of linalool, benzeneacetaldehyde, hexanal, methyl salicylate, and geraniol, the CARS–least-squares support vector machine model's correlation coefficients were 0.89, 0.95, 0.88, 0.80, and 0.78, respectively. The interaction mechanism of array dyes with VOCs was based on density flooding theory. The optimized highest occupied molecular orbital levels, lowest unoccupied molecular orbital energy levels, dipole moments, and intermolecular distances were determined to be strongly correlated with interactions between array dyes and VOCs.

Detection of volatile organic compounds in adulterated tea using Fourier transform infrared spectroscopy and Proton-transfer-reaction mass spectrometry

Aroma is a key factor used to evaluate tea quality. Illegal traders usually add essence to expired or substandard tea to improve its aroma so as to gain more profit. Traditional physical and chemical testing methods are time-consuming and costly. Furthermore, rapid detection techniques, such as near-infrared spectroscopy and machine vision, can only be used to detect adulterated powdered solid essences in tea. In this study, proton-transfer reaction mass spectrometry (PTR-MS) and Fourier-transform infrared spectroscopy (FTIR) were employed to detect volatile organic compounds (VOCs) in samples, and rapid detection of different tea adulterated liquid essence was achieved. The prediction accuracies of PTR-MS and FTIR reached over 0.941 and 0.957, respectively, and the minimum detection limits were lower than the actual used values in both. In this study, the different application scenarios of the two technologies are discussed based on their performance characteristics.

Revealing the influence of microbiota on the flavor of kombucha during natural fermentation process by metagenomic and GC-MS analysis

In this work, raw Pu-erh tea (RAPT) was employed for kombucha preparation, and the microbial composition and volatile flavor compounds of the fermented tea had been investigated during natural fermentation process. The head space-solid phase microextraction-gas chromatograph mass spectrometry (HS-SPME-GC-MS) was performed for volatiles analysis of unfermented tea and kombucha fermented for 3 days (KF-3) and 6 days (KF-6). Meanwhile, the microbial community of KF-3 and KF-6 were evaluated by metagenomic analysis. A total of 72 volatile compounds were identified and obvious changes in volatiles were observed during the fermentation process based on the results of GC-MS and principal component analysis (PCA). Metagenomic sequencing analysis demonstrated that bacterium Komagataeibacter saccharivorans and unclassified-g-komagataeibacter and yeast Saccharomyces cerevisiae and Brettanomyces bruxellensis were the most common microbes contained in the sampled kombucha communities. Furthermore, the relevance among microbial community and volatile compounds was evaluated through correlation heatmap analysis. The results suggested that the main flavor volatiles of kombucha (i.e., acids, esters and terpenes) were closely related to species of genus Komagataeibacter, Gluconacetobacter, Saccharomyces, Brettanomyces, Acetobacter, Novacetimonas and Pichia microorganisms. The obtained results would help to better understand microbial communities and volatile compounds of kombucha, which could provide useful information for enhancing the flavor quality of kombucha products.

Study on Tea Consumption Behavior During the Covid-19 Pandemic and the Analysis of the Antioxidant Activity and Bioactive Compounds of Flavoring Ingredients of Tea

Tea is one of the most popular and oldest beverages available in many varieties and the use of different flavoring ingredients is becoming more common. The present study aimed to examine tea consumption behavior during the COVID-19 pandemic and analyzed the bioactive compounds of tea flavoring ingredients. At first, a cross-sectional study was carried out with 140 randomly selected participants to determine tea consumption patterns and data was collected through face-to-face interviews. Then 2,2-diphenyl-1-picrylhydrazyl (DPPH) test, the Folin-Ciocalteu technique, and the quercetin method were used to assess antioxidant activity, total phenolic content (TPC), and total flavonoid content (TFC) of tea flavoring ingredients. The study found that 57.86% of the participants increased their tea consumption during the COVID-19 pandemic, whereas 22.80% increased their tea consumption by at least one more cup per day. It was also found that ginger was the most popular (29.5%) among fifteen tea flavoring agents. By analyzing tea flavoring ingredients, the maximum antioxidant activity found in cinnamon was 87%, and lemon leaves had the lowest, which was 60%. On a dry weight basis, the TPC of the tea flavoring components ranged from 36.52 mg GAE/g for cloves to 9.62 mg GAE/g for ginger. The maximum TFC was also found in clove with 13.68 mg QE/g, and moringa was the second highest with 12.26 mg GAE/g. The antioxidant activity of flavoring compounds has a significant correlation (p<0.05) with TPC and TFC. Overall, tea consumption behavior with tea flavoring ingredients increased during the COVID-19 pandemic situation. Tea with flavoring ingredients may be one of the best dietary sources of antioxidants, TPC, and TFC which are important for strengthening the immune system and controlling different physiological and metabolic disorders.

Genes cloning, sequencing and function identification of recombinant polyphenol oxidase isozymes for production of monomeric theaflavins from Camellia sinensis

Theaflavins (TFs) are important quality compounds in black tea with a variety of biological activities. However, direct extraction of TFs from black tea is inefficient and costly. Therefore, we cloned two PPO isozymes from Huangjinya tea, termed HjyPPO1 and HjyPPO3. Both isozymes oxidized corresponding catechin substrates for the formation of four TFs (TF1, TF2A, TF2B, TF3), and the optimal catechol-type catechin to pyrogallol-type catechin oxidation rate of both isozymes was 1:2. In particular, the oxidation efficiency of HjyPPO3 was higher than that of HjyPPO1. The optimum pH and temperature of HjyPPO1 were 6.0 and 35 °C, respectively, while those of HjyPPO3 were 5.5 and 30 °C, respectively. Molecular docking simulation indicated that the unique residue of HjyPPO3 at Phe260 was more positive and formed a π-π stacked structure with His108 to stabilize the active region. In addition, the active catalytic cavity of HjyPPO3 was more conducive for substrate binding by extensive hydrogen bonding.

Effect of phenolic compounds Extraction of Green tea (Camellia sinsis. L) On the Glutathione of Alloxan Experimental InducedDiabeticRabbit.

Diabetes Mellitus is considered as a member of oxidative stress syndrome. It is associated with an imbalance between types of free radicals and scavenger's system. This study showed the effect of the polyphenol compounds extracted from green tea (Camellia Sinesis L) on alloxan induced diabetic rabbits to determine their role in treatment of diabetes mellitus, their effect on enzymatic antioxidant and to know the histological effects on the diabetic kidney. The rabbits group was divided into five groups, cach group consist of 10 rabbits. The blood and tissue samples from these groups were taken for analysis and the result were as follow: There was a significant increase in Glucose .when polyphenol extract of green tea was used gave a significant decrease in all parameters (p<0.05) with dose rate of 100mg/kg of body weigt,200mgrkg of body weight as compared with diabetic group. There was a significant decrease in glutathione. When polyphenol extract of green tea was used with dose rate 100mg /kg of body weight gave a significant increase (p<0.05) in all parameters as compared with diabetic group.In comparison between the efficacy of herbs polyphenol compound in green tea. glibeneclamide it was appeared that the herbs are the better based on ¢ cy on treatment of diabetes and their effect on glucose and glutathione. The present results revealed that alloxan was effectively induced diabetes by partial destruction of b-cells of pancreas which lead to elevation of bload glucose level. As a consequence of hyperglycemia the abnormal effect was obvious in certain tissues in the body which attributed to the effect of diabetes Histological investigations shows that all the lesions in the kidney that result from diabetes such as hypertrophy, degeneration and hylanosis of the glomeruli.

Development of ready-to-drink tea with Lactobacillus plantarum Dad-13 based on the vulnerability aspects of the production process

Tea is one of the plantation crops which contributes to 3.27% of the Gross Domestic Product (GDP) in Indonesia. As one of Indonesia’s export commodities, tea plays a big role in foreign exchange revenue. Among various kinds of processed tea drinks, 14.36% of tea consumers in Indonesia have a preference for consuming ready-to-drink (RTD) tea, implying its market potential in Indonesia. Furthermore, the increasing trend of healthy products resulted in the rise of the probiotic beverage market globally. Therefore, an RTD tea product with the addition of Lactobacillus plantarum Dad-13 has been developed, named ProbioTea. This study discusses the development of the ProbioTea product and vulnerability analysis of the two processes used: cold brew and hot brew. The study aimed to determine the level of vulnerability at each stage of ProbioTea manufacturing to reduce the risk of failure in large-scale production. This study also investigated antioxidant contents, cell viability, pH, and the visual appearance of ProbioTea. The result showed that the mixing and storage process has a high vulnerability to both cold and hot brew methods. The result of the assessment of risk vulnerability in the ProbioTea production process showed no risk with an extreme level of vulnerability. Thus, it indicated that the risk in the ProbioTea production process can be managed properly. The percentage of antioxidants in the cold brewing method was 51.25 - 71.76%, while the hot brewing method shows 44.89 - 54.74%. After storage, ProbioTea with the cold brew method experienced an increase in antioxidants because the low temperature was able to protect the bioactive compounds in tea. Meanwhile, there was no significant difference in the cell viability of ProbioTea processed on the cold and hot brew. After storage, the cell viability contained in ProbioTea was more than 6.8 CFU/mL. The acidity of ProbioTea processed in both cold and hot brew was not significantly different. This research concluded that the ProbioTea product is good.

Study on the Effects of Processes on Aroma Compounds in Rizhao Green Tea Based on the Gas Chromatography-Ion Mobility Spectrometry

Tea processing plays an important role in the formation of tea aroma. In order to explore the composition and variation in aroma during Rizhao green tea processing, gas chromatography-ion mobility spectrometry was employed to investigate the formation and changes of tea aroma in four processing stages. A total of 62 volatile compounds were identified, including alcohols, aldehydes, ketones, esters, terpenes, and oxygen compounds. Relative odor activity value was used to identify 17 characteristic aroma compounds. The main aromatic compounds of chestnut-like aroma were linalool, pentanal, hexanal, heptanal, octanal, nonanal, 2-methylbutanal, 3-methylbutanal, 3-methylthiopropanal, and methyl 2-methylbutanoate. There were significant changes in the volatile components at different processing stages. Samples of tea leaves and green tea had special aroma characteristics, while samples of fixated and rolled leaves had similar aroma compounds. The results are beneficial for the improvement of the flavor and quality of Rizhao green tea. Practical Application. Tea is the world’s most consumed nonalcoholic beverage, with a multitude of health-promoting benefits, such as antioxidant, antiobesity, and antiallergic activities. At present, the research on the aroma compounds of Rizhao green tea mainly focuses on the aroma characteristics of finished tea and the aroma differences of different kinds of commercial tea. This study explored the effects of the processes on aroma compounds, and the results provide a theoretical reference for the improvement of tea processing technology, tea quality control, and evaluation methods.

Potential protective function of green tea polyphenol EGCG against high glucose-induced cardiac injury and aging

Green tea and its active extracts have been widely used in a variety of dietary supplements. However, to date, the interaction of these bioactive compounds in green tea and their protein targets are not well studied. We first used the bioinformatics analysis of the relevant diabetes-related targets with the green tea bioactive compounds target proteins to construct a protein interaction (PPI) network to screen the core targets. The results of in vitro experiments showed that EGCG, a major polyphenolic component of green tea, inhibited HG-induced cardiomyocyte hypertrophy, inflammation, oxidative stress response, and cellular senescence. It was found that the PPARG-dependent pathways were involved in the protective effects of EGCG against HG-induced myocardial injury and senescence. This study comprehensively explored the role of EGCG in high glucose-induced myocardial cell injury and aging.

Effects of leaf-spreading on the volatile aroma components of green tea under red light of different intensities

Spreading is an indispensable process in the aroma formation of green tea. The application of exogenous red-light spreading in tea processing has been verified to significantly improve the aroma of green tea, and endow tea with freshness, sweet flavor, and mellow taste. However, there were no previous studies investigating the effects of spreading with different red-light intensities on the aroma components of green tea. The aim of the present study was to evaluate the effect of the relationship between the aroma component and spreading with different red-light intensities (300 μmol∙m−2∙s−1, 150 μmol∙m−2∙s−1 and 75 μmol∙m−2∙s−1). As a result, a total of ninety-one volatile components were identified in this study. The orthogonal partial least squares discriminant analysis (OPLS-DA) model clearly distinguished the volatile components of green tea between different red-light intensities and obtained thirty-three differential volatile compounds. Combined with odor activity value (OAV > 1) analysis revealed that eleven volatile components were the key volatile compounds of green tea under different light conditions. Among them, 3-methyl-butanal, (E)-nerolidol, and linalool were the sources of chestnut-like aroma in green tea and were significantly accumulated under medium (MRL) and low intensity (LRL) red light. The results of the present study provided a theoretical basis that could guide green tea processing with red-light intensities to increase the aroma quality components of green tea.

Effects of processing procedures on the formation of aroma intensity and odor characteristic of Benshan tea (Oolong tea, Camellia sentences)

Benshan tea is a kind of oolong tea, and Benshan (Camellia sinensis) tea tree originates from Anxi County of Fujian Province in China, which is a national tea tree breed. Tea processing is the key to the formation of its odor characteristics. It is extremely important to step by step analyze effects of tea processing on aroma intensity and the formation of odor characteristics for optimizing tea processing process and improving tea quality. The results of this study showed that processing resulted in a significant increase in the content of volatile compounds in tea leaves, i.e., from 25.213 μg/kg to 111.223 μg/kg, in which the volatile compounds were mainly terpenoids. Secondly, the analysis found that 20 kinds of key compounds constituted to odor characteristics of Benshan tea leaves, among which geraniol, trans-β-ionone, gerol, citronellol, benzeneacetaldehyde, and trans-nerolidol were the most key six. Floral and fruity aromas, especially floral aroma, mainly formed odor characteristics of Benshan tea after processing, while floral aroma mainly came from the contribution of geraniol, which was the foremost compound in the formation of floral aroma of Benshan tea.