摘要：
Summer-autumn tea leaves are abundant, yet their utilization remains low. Our study enhances the quality and flavor of Golden Flower loose tea (GFLT) from fresh summer-autumn tea leaves by using a special "Golden Flower" fungus (strain ACF-2). The strain ACF-2, identified as Aspergillus cristatus with yellow cleistothecium and isolated from Fu Brick Tea, was characterized by colony morphology, microstructural analyses, and phylogenetic examination using a 3-gene dataset (BenA, CaM, RPB2). Inoculation of raw dark tea products with A. cristatus led to a significant increase in tea water extract and a reduction in tea polyphenols, soluble sugars, flavonoids, and total amino acids, thereby enhancing the quality and flavor of GFLT. HS-SPME-GC-MS analysis of GFLT aroma revealed that A. cristatus substantially improved the tea's aroma profile. 9 volatile compounds-(Z)-jasmone I, beta-cyclocitral, linalool oxide I, linalool, hexanal, 1-octen-3-ol, (Z)-citral, citral, and methyl salicylate, were found to be significantly elevated in GFLT compared to the controls. Our findings provide both theoretical and practical insights into optimizing the utilization of summer-autumn tea leaves, identifying the "Golden Flower" fungus, and understanding its impact on GFLT quality. In summary, fermenting A. cristatus to produce GFLT may be a new channel to utilize summer-autumn tea.
通讯作者：
Jian'an Huang<&wdkj&>Zhonghua Liu<&wdkj&>Jian'an Huang Jian'an Huang Jian'an Huang<&wdkj&>Zhonghua Liu Zhonghua Liu Zhonghua Liu
作者机构：
[Hongzhe Zeng; Kuofei Wang; Changwei Liu; Jie Ouyang; Shuai Wen; Fang Zhou; Jingyi Tang; Wenwen Fang; Lin Yue; Jian'an Huang; Zhonghua Liu; Hongzhe Zeng Hongzhe Zeng Hongzhe Zeng; Kuofei Wang Kuofei Wang Kuofei Wang; Changwei Liu Changwei Liu Changwei Liu; Jie Ouyang Jie Ouyang Jie Ouyang; Shuai Wen Shuai Wen Shuai Wen; Fang Zhou Fang Zhou Fang Zhou; Jingyi Tang Jingyi Tang Jingyi Tang; Wenwen Fang Wenwen Fang Wenwen Fang; Lin Yue Lin Yue Lin Yue; Jian'an Huang Jian'an Huang Jian'an Huang; Zhonghua Liu Zhonghua Liu Zhonghua Liu] Key Laboratory of Tea Science of Ministry of Education, National Research Center of Engineering and Technology for Utilization of Botanical Functional Ingredients, Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Key Laboratory for Evaluation and Utilization of Gene Resources of Horticultural Crops, Ministry of Agriculture and Rural Affairs of China, Hunan Agricultural University, Changsha, China
通讯机构：
[Jian'an Huang; Zhonghua Liu; Jian'an Huang Jian'an Huang Jian'an Huang; Zhonghua Liu Zhonghua Liu Zhonghua Liu] K;Key Laboratory of Tea Science of Ministry of Education, National Research Center of Engineering and Technology for Utilization of Botanical Functional Ingredients, Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Key Laboratory for Evaluation and Utilization of Gene Resources of Horticultural Crops, Ministry of Agriculture and Rural Affairs of China, Hunan Agricultural University, Changsha, China
摘要：
(1) This study may be the first study to evaluate the effects of oolong tea with different storage time in db/db T2DM mice.(2) All three aged oolong tea extracts (2001, 2011, 2020) can effectively alleviate type 2 diabetes mellitus (T2DM), and 2011 aged oolong tea extract exhibited relatively optimal ability to alleviate T2DM.(3) With storage time of oolong tea increasing, oolong tea’s ability to inhibit fat ectopic deposition in liver increases and the ability to activate INSR/IRS/PI3K/AKT/GSK‐3β/GYS‐mediated hepatic glycogen synthesis signaling pathway decreases. Abstract An important concern for tea consumers is whether appropriate storage can effectively improve the ability of oolong tea to alleviate type 2 diabetes mellitus (T2DM). In this study, the antidiabetic effects of three aged oolong tea (2001, 2011, and 2020) extracts (aged TEs) in db/db T2DM mice were investigated and compared for the first time. The results showed that aged oolong tea extracts (aged TEs) alleviated the abnormal fasting blood glucose levels, lipid profiles, insulin resistance, and reduced ectopic fat deposition in liver. Moreover, aged TEs alleviated T2DM‐related tissue damage and activated insulin receptor (INSR)/insulin receptor substrate (IRS)/phosphatidylinositol‐3 kinase (PI3K)/phosphatidylinositol‐3 kinase (AKT)/glycogen synthase kinase 3 beta (GSK‐3β)/glycogen synthase (GYS)‐mediated hepatic glycogen synthesis signaling pathway. In addition, aged TEs altered gut microbiota composition and gut metabolite profiles associated with T2DM. Together, all three aged TEs (400 mg/kg/day in mice, a human equivalent dose of 7 g/60 kg/day), especially 2011, can effectively alleviate T2DM, and proper storage can effectively improve the ability of oolong tea to alleviate T2DM.
摘要：
The objective of this study is to explore the influence of extraction factors, including extraction temperatures, extraction time, and tea-water ratios, on the sensory quality and aroma characteristics of instant Pu-erh tea (IPET). Sensory evaluation, quantitative descriptive analysis (QDA) and HS-SPME-GC x GC-TOF/MS were utilized for analysis. The result showed that the optimal process condition of IPET was a tea-to-water ratio 1:8, an extraction temperature 75 C-degrees, and an extraction time 60 min. A total of 235 volatile compounds were identified and 65 key odor-active compounds with ROAV>1 in all samples. Based VIP > 1, 19 key differential odor-active compounds were identified, including linalool oxide I, 1-dodecanol, linalool oxide II, etc. Further Pearson correlation analysis of key differential odor-active compounds and aroma characteristics showed that positive correlations between woody and ethyl nonanoate and 1-dodecanol, and between herbal and 1-methylnaphthalene. This research provides theoretical support for the production of high-quality IPET.
摘要：
Liquid chromatography-mass spectrometry (LC-MS) combined with multivariate analysis were used to characterize the nonvolatile compounds of broken green tea and explore the effect of isolated scenting on metabolic profile and taste quality of broken green tea in this research. A total of 236 nonvolatile compounds were identified and 13 compounds were believed to be the key characteristic taste compounds of scented broken green tea. Meanwhile, the optimal isolated scenting time of broken green tea was determined to be 10h based on the sensory evaluation and PLS results. The contents and types of flavonoids, organic acids and catechins lead to the difference of taste quality at different scenting times. Overall, these findings provided a theoretical basis for scenting to improve the taste of broken green tea, and provide a new idea for improving the taste of broken green tea.
摘要：
As one of the most abundant plant polyphenols in the human diet, (-)-epicatechin (EC) can improve insulin sensitivity and regulate glucose homeostasis. However, the primary mechanisms involved in EC anti-T2DM benefits remain unclear. The present study explored the effects of EC on the gut microbiota and liver transcriptome in type 2 diabetes mellitus (T2DM) Goto-Kakizaki rats for the first time. The findings showed that EC protected glucose homeostasis, alleviated systemic oxidative stress, relieved liver damage, and increased serum insulin. Further investigation showed that EC reshaped gut microbiota structure, including inhibiting the proliferation of lipopolysaccharide (LPS)-producing bacteria and reducing serum LPS. In addition, transcriptome analysis revealed that the insulin signaling pathway may be the core pathway of the EC anti-T2DM effect. Therefore, EC may modulate the gut microbiota and liver insulin signaling pathways by the gut-liver axis to alleviate T2DM. As a diet supplement, EC has promising potential in T2DM prevention and treatment.
摘要：
Obesity is associated with gut dysbiosis and metabolic endotoxin. Junshanyinzhen tea extract ( JSTE) reduced fat accumulation and body weight in obese mice. However, the effects and mechanism of JSTE in preventing obesity were unclear. Therefore, we used different doses of JSTE (75, 150 and 300 mg/(kg<middle dot>day)) to evaluate the effect on high-fat diet (HFD)-induced rats under 8 weeks of intervention. Here, our results showed that JSTE could significantly reduce body weight gain, blood lipid levels and fat accumulation, improve fatty damage in liver tissue (P < 0.05). In addition, JSTE increased the expression of intestinal tight junction proteins (P < 0.05), relieved metabolic endotoxemia (P < 0.05) and chronic low-grade inflammation in HFD rats. Sequencing of fecal samples showed that JSTE could effectively reverse the microbial diversity and the ratio of Firmicutes to Bacteroidetes to normal levels in HFD-fed rats. Desulfovibrioceae and Erysipelotrichaceae, which are positively related to obesity, were decreased by JSTE intervention (P < 0.05). while Bifidobacteriaceae, Bacteroidaceae, Akkermansia, and Clostridium, which are negatively related to obesity, were increased. Together, these results suggested that JSTE might effectively prevent obesity by modulating gut microbiota dysbiosis, intestinal barrier dysfunction, metabolic endotoxemia and chronic lowgrade inflammation in HFD-induced rats. (c) 2024 Beijing Academy of Food Sciences. Publishing services by Tsinghua University Press. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
关键词：
Fu Brick Tea;Sensomics analysis;Aroma recombination and omission;Key odor-active compounds;Bacterial community
摘要：
Fu Brick Tea (FBT) is a unique fermented tea produced in multiple regions of China, whose aroma qualities, key odor-active compounds and bacterial communities are not well characterized. By optimizing HS-SPME methods, utilizing GC-MS, GC-O, sensory analysis, aroma recombination and omission experiments, and bacterial sequencing, we revealed the primary volatiles and bacterial communities in 41 samples from 7 major producing regions. A total of 63 volatiles and 32 odor-active compounds were quantitatively analyzed using GC-MS and GC-O, respectively. Sensory analyses discriminated the quality of the samples. Differential analysis indicated that poor aroma FBTs had either low volatile content or excessive "green" notes. Key odor-active compounds in highquality aroma FBTs include 1-octen-3-ol, phenylethylalcohol, beta-ionone, dihydroactindiolide, and 1,2,3-trimethoxybenzene. Sequencing results identified Bacillus, Pseudomonas, and Streptococcus as dominant genera. Functional prediction analyses suggest that bacteria contribute to the formation of FBT aroma. This study offers new insights into the quality characteristics of FBT.
关键词：
Raw pu-erh tea;Flavor profiles;Volatile compounds;Geographical attributes;Multivariate statistical analysis
摘要：
The Chinese proverb "One mountain, one flavor" reflects that raw pu-erh tea (RPT) from different tea-producing mountains (TPMs) possesses distinct flavor profiles. However, limited research has been conducted on the chemical composition underlying distinct flavor profiles. In this study, sensory evaluation and main phytochemical compositions revealed diverse aromas of RPTs from 26 TPMs. A total of 225 volatile compounds were analyzed qualitatively and quantitatively by comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry, including hydrocarbon compounds, ketones, alcohols, and aldehydes. Furthermore, twentyone common key odor-active compounds, potentially influencing the regional flavor, were identified by gas chromatography-olfactometry and odor activity value. Multivariate statistical analysis showed that geographical factors-longitudes, latitudes, counties, and elevations-account for 37.02 % of the aroma profile variance, implying the possible influence of other potential factors. The study results serve as a reference for a better understanding of the correlation between the RPT flavor characteristics and geographical attributes in TPMs.
通讯机构：
[Yin, X ; Liu, ZH ] H;Hunan Agr Univ, Key Lab Tea Sci, Minist Educ, Changsha 410128, Peoples R China.;Natl Res Ctr Engn & Technol Utilizat Bot Funct Ing, Changsha 410128, Peoples R China.;Hunan Acad Agr Sci, Tea Res Inst, Dept Tea Qual Chem & Nutr Hlth, Hunan Tea Plant & Tea Proc Observat Stn,Minist Agr, Changsha 410125, Peoples R China.;Minist Utilizat Bot Funct Ingredients, Coinnovat Ctr Educ, Changsha 410128, Peoples R China.
关键词：
shaken Hunan black tea;leaves grade;taste;aroma;HS-SPME/GC-MS
摘要：
<jats:p>Shaken Hunan black tea is an innovative Hunan black tea processed by adding shaking to the traditional Hunan black tea. The quality of shaken black tea is influenced by leaf grades of different maturity. In this study, the taste and aroma quality of shaken Hunan black tea processed with different grades were analyzed by sensory evaluation (SP, HPLC, and HS-SPME/GC-MS). The results showed that shaken Hunan black tea processed with one bud and two leaves has the best quality, which has a sweet, mellow, and slightly floral taste, as well as a floral, honey, and sweet aroma. Moreover, caffeine and EGCG were identified as the most important bitter and astringent substances in shaken Hunan black. Combined with the analysis of GC-MS and OAV analysis, geraniol, jasmone, β-myrcene, citral, and trans-β-ocimene might be the most important components that affect the sweet aroma, while methyl jasmonate, indole, and nerolidol were the key components that affect the floral aroma of shaken Hunan black tea. This study lays a foundation for this study of the taste and aroma characteristics of shaken Hunan black tea and guides enterprises to improve shaken black tea processing technology.</jats:p>
摘要：
Catechins, among the most active components in tea, effectively alleviate obesity. Catechins are primarily classified into four types based on the presence or absence of the C-3 galloyl group and the B-5' hydroxyl group. However, the impact of conformation on the anti-obesity properties of catechins remains unclear. Findings indicate that the C-3 galloyl group and the B-5' hydroxyl group significantly enhance the biological activity of catechins, aiding in obesity alleviation, regulating glycolipid metabolism, reducing hepatic steatosis, lowering serum lipopolysaccharide (LPS) levels, and promoting the proliferation of Akkermansia muciniphila. Further investigation revealed that Akkermansia muciniphila may modulate LPS/insulin resistance to protect glycolipid metabolic homeostasis, attenuate liver tissue damage, and promote catechin metabolism to generate new bioactive components. Overall, the C-3 galloyl group and the B-5' hydroxyl group may modulate the gut-liver axis through the bidirectional interplay between catechins and Akkermansia muciniphila, thereby enhancing the anti-obesity activity of catechins.
通讯机构：
[Liu, ZH; Huang, JA ] H;Hunan Agr Univ, Minist Educ, Key Lab Tea Sci, Changsha 410128, Peoples R China.
关键词：
Different grades;Huangpu black tea;Metabolomics;Sensory histology techniques
摘要：
Significant differences exist in aroma and taste of different grades of large-leaf black tea. In this study, sensory histology combined with metabolomics were used to investigate the sensory characteristics and phytochemical profiles of different grades of Huangpu black tea (HPBT). Sensory evaluation showed that high grade HPBT had high intensity of pekoe, fresh aroma and umami, with aroma and taste scores declining with decreasing grades. 173 non-volatiles were identified, of which 23 marker metabolites could be used as discrimination of different grades HPBT taste. In addition, 154 volatile compounds were identified in the different grades of HPBT, with 15 compounds as key odorants for distinguishing the aroma of different grades of HPBT. Furthermore, correlation analysis revealed that linalool, geraniol and nonanal contributed to the aroma quality score of HPBT. This study will provide a more comprehensive understanding for processing, quality evaluation and grade evaluation system of large-leaf black tea.
摘要：
Background: Theaflavins (TFs) are orange-red pigments with a benzotropolone structure, which are formed by the polymerization of catechins under oxidase-catalysed oxidation in the fermentation stage of black tea production. The contents of TFs play a crucial role in determining the sensory properties and commercial value of black tea. As natural bioactive compounds, TFs exhibit biological activities, which highlight their potential applications in the food, pharmaceutical, and healthcare industries. However, compared to the extensive applications of tea catechins, TFs remain underexploited due to technical challenges in their preparation. A comprehensive understanding of current TFs preparation technologies is essential for the development of novel processing techniques. Scope and approach: This review provides a summary of the formation mechanism of TFs, with an emphasis on the key techniques employed for their extraction and purification. Additionally, it thoroughly examines the impact of synthetic methods and their corresponding influencing factors on TFs synthesis. Recent research advancements in the biological activities of TFs are also discussed succinctly. Key findings and conclusion: Significant advancements in the synthesis, extraction, and purification techniques of TFs have been made in laboratory settings; however, challenges remain in scaling up these processes for mass production and practical applications. Exploring the directional synthetic processes for TFs, developing automated systems for continuous extraction, separation, and concentration, and elucidating the mechanisms underlying the biological activities of different TF monomers should be the focus of future research.
摘要：
Background: The worldwide prevalence of metabolic syndrome (MS) and obesity has led to the exploration of tea consumption as a potential strategy for managing these conditions. However, the clinical outcomes remain debated. We conducted a meta-analysis to evaluate the benefits of tea supplementation in MS and obesity entirely based on randomized controlled trials (RCTs). Methods: Databases of PubMed, Cochrane library, MEDLINE and Web of Science were searched through May 2023 to identify eligible RCTs evaluating the effects of tea supplementation related to MS and obesity. Results were summarized using standardized mean differences (SMDs) by suitable effect model. Results: A total of 24 RCTs were screened, including 1672 subjects from 8 countries. Tea supplementation reduced body weight (BW) (SMD:-0.14; 95%CI:-0.26,-0.03; P = 0.013), body mass index (BMI) (SMD:- 0.15; 95%CI:-0.26,-0.03; P = 0.016), triglycerides (TG) (SMD:-0.21; 95% CI:-0.41,-0.01; P = 0.044), total cholesterol (TC) (SMD:-0.23; 95% CI:-0.44,-0.02; P = 0.033), low-density lipoprotein cholesterol (LDLC) (SMD:-0.28; 95% CI:-0.5,-0.05; P = 0.016) and hemoglobin A1c (HbA1c) (SMD:-0.35; 95% CI:-0.60,- 0.1; P = 0.007) levels, increased high-density lipoprotein (HDL) (SMD: 0.13; 95% CI: 0.01, 0.25; P = 0.04) levels versus Placebo. Conclusion: This meta-analysis presents convincing evidence of the potential advantages of tea consumption for individuals with MS and obesity. Compared with control group, tea consumption can significantly reduce BW, BMI, and lipid profiles (HDL-C, LDL-C, TG, TC) levels of obesity and MS patients. This beneficial effect highlights the prospect of tea as a beneficial dietary strategy in addressing these medical conditions.
摘要：
Dark tea (DT) holds a rich cultural history in China and has gained sizeable consumers due to its unique flavor and potential health benefits. In this study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS), relative odor activity value (ROAV), and chemometrics approaches were used to detect and analyze aroma compounds differences among five dark teas from different geographical regions. The results revealed that the five DTs from different geographical regions differed in types, quantities, and relative concentrations of volatile compounds. A total of 1372 volatile compounds of were identified in the 56 DT samples by HS-SPME-GC-MS. Using ROAV and chemometrics approaches, based on ROAV>1 and VIP>1. Eighteen key aroma compounds can be used as potential indicators for DT classification, including dihydroactinidiolide, linalool, 1,2,3-trimethoxybenzene, geranyl acetone, 1,2,4-trimethoxybenzene, cedrol, 3,7-dimethyl-1,5,7-octatrien-3-ol, β-ionone, 4-ethyl-1,2-dimethoxybenzene, methyl salicylate, α-ionone, geraniol, linalool oxide I, linalool oxide II, 6-methyl-5-hepten-2-one, α-terpineol, 1,2,3-trimethoxy-5-methylbenzene, and 1,2-dimethoxybenzene. These compounds provide a certain theoretical basis for distinguishing the differences in five DTs from different geographical regions. This study provides a potential method for identifying the volatile substances in DTs and elucidating the differences in key aroma compounds. Abbreviations: DT, dark tea; FZT, Fuzhuan tea; LPT, Guangxi Liupao tea; QZT, Hubei Qingzhuan tea; TBT, Sichuan Tibetan tea; PET, Yunnan Pu-erh tea; ROAV, Relative odor activity value; OT, Odor threshold; HS-SPME, Headspace solid-phase microextraction; GC-MS, Gas chromatography-mass spectrometry; PCA, Principal components analysis; PLS-DA, Partial least squares-discriminant analysis; HCA, Hierarchical clustering analysis.
关键词：
Camellia sinensis;Electronic eye;Electronic nose;Nontargeted analysis;Polyphenols;Six types of tea;Targeted analysis
摘要：
Tea polyphenols transform under processing methods, but a systematic study on their changes in the same large-leaf tea cultivar is lacking. Here, Camellia sinensis var. assamica cv. Yunkang-10 leaves underwent six processing methods and were assessed using optimized nontargeted (UHPLC-Q-Exactive Orbitrap-MS) and targeted (UHPLC-QqQ-MS) polyphenomics, along with molecular networking analysis. 903 and 52 polyphenolic compounds (catechins, flavones and flavonols, and phenolic acids) were respectively relatively and absolutely quantified for the first time. Dark and black teas, with the lowest polyphenol content, differed from the other four tea types, although variations existed among these four teas. However, some flavonol and flavone aglycones (e.g. kaempferol, apigenin), as well as some phenolic acids (e.g. ellagic acid, gallic acid), exhibited higher levels in dark and black teas. Correlations between polyphenolic composition and electronic sensory characteristics were observed using E-tongue and E-eye. This study enriches understanding of polyphenol profiles in Chinese teas post diverse processing.
摘要：
Dietary management and interventions are crucial in the clinical management of diabetes. Numerous active dietary components in black tea have demonstrated positive effects on blood glucose levels and metabolic functions. However, limited research has explored the potential of theaflavins (TF), polyphenols in black tea, for diabetes management. In this study, high-purity TF was administered to Goto-Kakizaki (GK) diabetic model rats for four weeks to investigate its impact on diabetic pathology and analyze the underlying mechanisms through liver transcriptomics, hepatocyte metabolomics, and gut microbiome analysis. The findings indicated that continuous administration of TF (100mg/kg) significantly suppressed blood glucose levels, reduced insulin resistance, and decreased the expression of oxidative stress indicators and inflammatory factors in GK rats. Further analysis revealed that TF might alleviate insulin resistance by improving hepatic glycogen conversion and reducing hepatic lipid deposition through modulation of key pathways, such as peroxisome proliferator-activated receptors and PI3K/AKT/GSK-3 pathways within the liver, thereby ameliorating diabetic symptoms. Additionally, TF intake facilitated the restoration of the intestinal microbial community structure by reducing the abundance of harmful bacteria and increasing the abundance of beneficial bacteria. It also reduced endotoxin lipopolysaccharide production, thereby lowering the chances of insulin resistance development and enhancing its efficacy in regulating blood glucose levels. These findings offer a novel perspective on the potential of black tea and its active constituents to prevent and treat diabetes and other metabolic disorders, providing valuable references for identifying and applying active dietary components from tea.
摘要：
Epigallocatechin-3-gallate (EGCG) is a main bioactive constituent in green tea. Being a redox-active polyphenol, high-dose EGCG exhibits pro-oxidative activity and could cause liver injury. L-theanine is a unique non-protein amino acid in green tea and could provide liver-protective effects. The purpose of this study was to investigate the hepatoprotective effects of L-theanine on EGCG-induced liver injury and the underlying mechanisms. A total of 300 mg/kg L-theanine was administrated to ICR mice for 7 days. Then, the acute liver injury model was established through intragastric administration of 1000 mg/kg EGCG. Pretreatment with L-theanine significantly alleviated the oxidative stress and inflammatory response caused by high-dose EGCG through modulation of Nrf2 signaling and glutathione homeostasis. Furthermore, metabolomic results revealed that L-theanine protects mice from EGCG-induced liver injury mainly through the regulation of amino acid metabolism, especially tryptophan metabolism. These findings could provide valuable insights into the potential therapeutic applications of L-theanine and highlight the importance of the interactions between dietary components.
作者机构：
[Wang, Kunbo; Shang, Bohao; Zhu, Mingzhi; Liu, Zhonghua; Zhou, Fang; Huang, Jianan] Hunan Agr Univ, Coll Hort, Changsha 410128, Peoples R China.;[Zhu, Mingzhi; Zeng, Xin] Huaibei Normal Univ, Coll Life Sci, Huaibei 235000, Peoples R China.;[Yin, Feiyan; Cao, Jin; Yuan, Yong] Hunan Tea Grp Co Ltd, Changsha 410128, Peoples R China.;[Li, Maiquan] Hunan Agr Univ, Sch Food Sci & Technol, Changsha 410128, Peoples R China.
通讯机构：
[Zeng, X ; Li, MQ ; Liu, ZH ] H;Hunan Agr Univ, Coll Hort, Changsha 410128, Peoples R China.;Huaibei Normal Univ, Coll Life Sci, Huaibei 235000, Peoples R China.;Hunan Agr Univ, Sch Food Sci & Technol, Changsha 410128, Peoples R China.
关键词：
Golden -flower fungus;Aspergillus cristatus;Polysaccharides;Obesity;Gut microbiota
摘要：
Golden -flower fungus, the only dominant microorganism determining the Fu -brick tea quality through fermentation and the important microbe in Liupao tea, is considered a potential probiotic fungus based on its anti -obesity effect. However, the classification of golden -flower fungi is still controversial; the anti -obesity effect of golden -flower fungus polysaccharides remains unknown. In this study, we identify a golden -flower strain as Aspergillus cristatus based on morphological characteristics and multigene phylogeny analysis, which resolves the controversy of classification. Moreover, we find A. cristatus polysaccharides (ACPS) attenuate obesity in rats. ACPS modulate gut bacterial composition, in which Akkermansia, Akkermansia muciniphila, Bacteroides, Romboutsia, Blautia, and Desulfovibrio are considered the core microbes regulated by ACPS. ACPS increase fecal total short -chain fatty acid content and serum, hepatic, and fecal total bile acid content. Furthermore, ACPS-induced gut microbiota alteration plays a causal role in the protection from obesity, according to a fecal transplantation experiment. Thus, ACPS ameliorate obesity by regulating gut microbiota and gut microbiota-related metabolites. (c) 2024 Beijing Academy of Food Sciences. Publishing services by Tsinghua University Press. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
关键词：
Anhua dark tea;Camellia sinensis;Electronic sensory evaluations;Metabolomics;Microbial fermentation;Volatolomics
摘要：
Anhua dark teas (DTs), including Tianjian tea, Qianliang tea, Hei brick tea, and Fu brick tea, are unique fermented teas from China's Anhua County; yet their chemical composition differences remain unclear. Herein, metabolomics, volatolomics, and electronic sensory assessments were employed to analyze and compare chemical compositions and sensory characteristics of five types of Anhua DTs. All of these teas were derived from identical tea materials. Chemical compositions differed significantly among Anhua DTs, with Tianjian tea remarkable. Long-lasting fermentation and complex processing methods led to transformation of multiple compounds, particularly catechins. Eighteen volatile compounds with OVA>1 were key aroma contributors in Anhua DTs. Internal transcribed spacer and 16S ribosomal DNA sequencing showed that Eurotium, Pseudomonas, and Bacillus are dominant microorganisms in Anhua DTs. Furthermore, this study unveiled notable differences in chemical compositions between Anhua DTs and five other traditional types of tea. This research enhances our understanding of Anhua DTs processing.
摘要：
This study investigates the dynamic changes in the aroma profile of Tuo tea during long-term storage, a process not well understood yet critical to the formation of aged tea's unique characteristics. Aroma profiling of Tuo tea samples stored for 2 to 25years was conducted using sensory evaluation and the HS-SPME/GC×GC-QTOFMS technique, revealing a progressive transition from fresh, fruity, and floral scents to more stale, woody, and herbal notes. Among 275 identified volatiles, 55 were correlated with storage duration (|r| > 0.8, p<0.05), and 49 differential compounds (VIP>1, FC>1.2, FC<0.833, p<0.05) were identified across three storage stages (2-4, 5-10, and 13-25years). Furthermore, theaspirane, eucalyptol, o-xylene, and 1-ethylidene-1H-indene were selected as potential markers of Tuo tea aging, incorporating the implementation of a Random Forest (RF) model. Additionally, our model exhibited high accuracy in predicting the age of Tuo tea within a prediction error range of -2.51 to 2.84years. This research contributes to a comprehensive understanding of the impact of storage time on tea aroma and aids in the precise identification of tea age.
