FOOD CONTROL
·
2022
·
IF 6.652
Wei Chen,Die Hu,Aiqing Miao,Guangjun Qiu,Xiaoyan Qiao,Hongling Xia,Chengying Ma
Dancong is a Chinese oolong tea famous for its aroma diversity. However, this diversity in characteristic is challenging to be clarified in either sensory or chemical aspects. In this study, the aromas from Dancong teas were characterized based on the typical odors of “floral” and “honey”. The volatile compounds underlying the odors were investigated through chemometrics. Seventy Dancong teas of various categories were collected to approximate the diversity in aroma. According to the sensory evaluation, the floral or honey odor was detected in every sample. For volatile characterization, 57 compounds were identified by gas chromatography-mass spectrometry (GC-MS) coupled with headspace-solid phase microextraction (HS-SPME) across samples. The difference in floral and honey odors was related to volatile variation among the teas, as both the odor-based classification and the volatile-based unsupervised learning analyses yielded consistent sample clustering patterns. Nine volatiles were identified as putative markers for the odor difference, where indole, ( E )-nerolidol, 2-phenylacetonitrile, and γ-caprolactone accounted for the floral odor predominance, while hexyl 2-methylbutanoate, ( Z )-3-hexenyl pentanoate, ( Z )-linalool oxide (pyranoid), ( E )-linalool oxide (furanoid), and ( Z )-linalool oxide (furanoid) contributed to the honey odor perception. These results point to a volatile-endorsed categorization framework based on the floral and honey odors that can assist in Dancong aroma quality control.
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PLANT FOODS FOR HUMAN NUTRITION
·
2011
·Vol. 66
·期 2
·169-174
·
IF 2.463
Chen Yulong,Jiang Yueming,Shi John,Xu Xinlan,Yang Shaoyu,Duan Jun
The contents of starch and catechins in the fresh leaf of ‘Huang Zhi Xiang’ Oolong tea trees girdled at the bottom, middle (on the big branches) and top (on the small branches) were determined. The study demonstrated that the starch contents from girdled trees were significantly higher ( p < 0.05) than that from non-girdled ones. Furthermore, the contents of (−)−epicatechin (EC), (−)−epigallocatechin (EGC), total catechins (TC) and simple catechins (SC) from girdled trees were significantly higher ( p < 0.05) than those from non-girdled ones. Especially, the contents of (−)−epigallocatechin gallate (EGCG), (−)−epicatechin gallate (ECG) and catechin gallate (CG) from girdled at the middle were also significantly higher ( p < 0.05) than those from the non-girdled. The starch contents were negatively correlated with the contents of (−)−gallocatechin (GC), EC, SC, TC and EGC, while positively correlated with the contents of EGCG and CG in fresh shoots.
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Foods
·
2024
·Vol. 13
·期 5
·753
·
IF 4.7
Xiaomei Wen,Shanjie Han,Jiahui Wang,Yanxia Zhang,Lining Tan,Chen Chen,Baoyu Han,Mengxin Wang
The storage period of tea is a major factor affecting tea quality. However, the effect of storage years on the non-volatile major functional components and quality of green tea remains largely unknown. In this study, a comparative analysis of organic green teas with varying storage years (1–16 years) was conducted by quantifying 47 functional components, using electronic tongue and chromatic aberration technology, alongside an evaluation of antioxidative capacity. The results indicated a significant negative correlation between the storage years and levels of tea polyphenols, total amino acids, soluble sugars, two phenolic acids, four flavonols, three tea pigments, umami amino acids, and sweet amino acids. The multivariate statistical analysis revealed that 10 functional components were identified as effective in distinguishing organic green teas with different storage years. Electronic tongue technology categorized organic green teas with different storage years into three classes. The backpropagation neural network (BPNN) analysis demonstrated that the classification predictive ability of the model based on the electronic tongue was superior to the one based on color difference values and 10 functional components. The combined analysis of antioxidative activity and functional components suggested that organic green teas with shorter storage periods exhibited stronger abilities to suppress superoxide anion radicals and hydroxyl radicals and reduce iron ions due to the higher content of eight components. Long-term-stored organic green teas, with a higher content of substances like L-serine and theabrownins, demonstrated stronger antioxidative capabilities in clearing both lipid-soluble and water-soluble free radicals. Therefore, this study provided a theoretical basis for the quality assessment of green tea and prediction of green tea storage periods.
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Food Chemistry-X
·
2026
·
IF 9.2
Chen Liu,Chenbo Wang,Mengyang Wei,Meiyi Ning,Zhiying Xu,Shengxiang Chen,Jilai Cui,Chuankui Song,Qian Tang
Leaf tenderness influences green tea quality, yet its role in flavour formation remains unclear. This study analysed green teas from Camellia sinensis cv. ‘Chuancha No. 2’ with three tenderness levels—single bud (C1B), one-bud with one-leaf (C1B1L), and one-bud with two-leaves (C1B2L)—via sensory evaluation, chemical profiling, and GC–MS analysis. C1B showed the best appearance and a chestnut-like, refreshing aroma. C1B1L featured floral notes and a mellow, umami taste, while C1B2L was stronger and more full-bodied. C1B had higher free amino acids and lower polyphenols and caffeine; C1B1L had the highest polyphenol content. Among 97 volatiles, 11 had ROAV > 1. Five common aroma compounds, namely 1-octen-3-ol, geraniol, hexanal, benzeneacetaldehyde, and 2-pentylfuran, were identified as key contributors to the aroma profile. Geraniol, most abundant in C1B1L, shaped its floral aroma. These origins are supported by established pathways, including lipid-derived oxidation products, glycoside-released geraniol, and amino-acid-derived benzeneacetaldehyde. This study clarifies how tenderness drives flavour divergence and identifies compounds supporting sensory variation in green tea.
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Food Chemistry-X
·
2024
·
IF 6.5
Chunyin Qin,Zisheng Han,Zongde Jiang,Jia-Ping Ke,Wen Li,Liang Zhang,Daxiang Li
In the present study, bud yellow tea (BYT), small-leaf yellow tea (SYT) and large-leaf yellow tea (LYT) were produced from the same local “population” variety Huoshanjinjizhong ( Camellia sinensis var. sinensis ), and the effects of raw material tenderness on the chemical profile and bioactivities of these teas were investigated. The results showed that 11 crucial compounds were screened by headspace solid-phase microextraction-gas chromatography–mass spectrometry from 64 volatiles in these yellow teas, among which the heterocyclic compounds showed the greatest variations. In addition, 43 key compounds including organic acids, flavan-3-ols, amino acids, saccharides, glycosides and other compounds were screened by liquid chromatography-mass spectrometry from 1781 non-volatile compounds. BYT showed the best α-glucosidase inhibitory activity and antioxidant capacity among the selected yellow teas, which might be contributed by the higher content of galloylated catechins. These findings provided a better understanding of the chemical profile and bioactivities of yellow teas.
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FOOD CHEMISTRY
·
2022
·
IF 9.231
Cong Chen,Fei Yu,Xinli Wen,Shuna Chen,Kaixi Wang,Feiquan Wang,Jianming Zhang,Yuanyuan Wu,Puming He,Youying Tu,Bo Li
Two major green leaf volatiles (GLVs) in tea that contribute greatly to tea aroma, particularly the green odor, are (E)-2-hexenal and (Z)-3-hexenal. Until now, their formation and related mechanisms during tea manufacture have remained unclear. Our data showed that the contents of (E)-2-hexenal and (Z)-3-hexenal increased more than 1000-fold after live tea leaves were torn. Subsequently, a new (Z)-3:(E)-2-hexenal isomerase (CsHI) was identified in Camellia sinensis . CsHI irreversibly catalyzed the conversion of (Z)-3-hexenal to (E)-2-hexenal . Abiotic stresses including low temperature, dehydration, and mechanical wounding, did not influence the (E)-2-hexenal content in intact tea leaves during withering, but regulated the proportions of (Z)-3-hexenal and (E)-2-hexenal in torn leaves by modulating CsHI at the transcript level. For the first time, this work reveals the formation of (E)-2-hexenal during tea processing and suggests that CsHI may play a pivotal role in tea flavor development as well as in plant defense against abiotic stresses.
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PLANT DISEASE
·
2019
·Vol. 103
·期 10
·
IF 3.583
Yuchun Wang,Fei Xiong,Qinhua Lu,Xinyuan Hao,Mengxia Zheng,Lu Wang,Nana Li,Changqing Ding,Xinchao Wang,Yajun Yang
Several Pestalotiopsis -like species cause gray blight disease in tea plants, resulting in severe tea production losses. However, systematic and comprehensive research on the diversity, geographical distribution, and pathogenicity of pathogenic species associated with tea plants in China is limited. In this study, 168 Pestalotiopsis -like isolates were obtained from diseased tea plant leaves from 13 primary tea-producing provinces and cities in China. Based on a multilocus (internal transcribed spacer, translation elongation factor 1-α, and β-tubulin gene region) phylogenetic analysis coupled with an assessment of conidial characteristics, 20 Neopestalotiopsis unclassified isolates, seven Pestalotiopsis species, including two novel ( Pestalotiopsis menhaiensis and Pestalotiopsis sichuanensis ), four known ( Pestalotiopsis camelliae , Pestalotiopsis chamaeropis , Pestalotiopsis kenyana , and Pestalotiopsis rhodomyrtus ) and one indistinguishable species, and three Pseudopestalotiopsis species, including two known ( Pseudopestalotiopsis camelliae-sinensis and Pseudopestalotiopsis chinensis ) and one indistinguishable species, were identified. This study is the first to evaluate Pestalotiopsis chamaeropis on tea plants in China. The geographical distribution and pathogenicity tests showed Pseudopestalotiopsis camelliae-sinensis to be the dominant cause of gray blight of tea plants in China. In vitro antifungal assays demonstrated that theobromine not only derepressed mycelial growth of the 29 representative isolates but also increased their growth. Correlation analysis revealed a linear positive relationship between the mycelial growth rate and pathogenicity ( P = 0.0148).
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Food & Function
·
2017
·Vol. 8
·期 12
·4619-4629
·
IF 3.247
Dan Chen,Guijie Chen,Peng Wan,Bing Hu,Ligen Chen,Shiyi Ou,Xiaoxiong Zeng,Hong Ye
In the present study, digestion under saliva, simulated gastric and small intestinal conditions and fermentation in vitro of polysaccharides from the flowers of Camellia sinensis (TFPS) by human gut microbiota were investigated. The results indicated that human saliva and simulated gastric and intestinal juices had no effect on TFPS, while TFPS could be utilized by human fecal microbiota, which was proved from the decreased molecular weight and lower content of total or reducing sugars after fermentation under anaerobic conditions. It was found that pH in the fermentation system decreased, and the production of short-chain fatty acids was significantly enhanced. Furthermore, in vitro fermentation of TFPS altered the composition of gut microbiota, specifically in elevating the ratio of Bacteroidetes to Firmicutes and enriching Prevotella. The present results suggest that TFPS has the potential to be developed as functional foods to modify gut microbiota.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2020
·
IF 4.192
Ying Zhou,Rufang Deng,Xinlan Xu,Ziyin Yang
Linalool is abundant in tea leaves and contributes greatly to tea aroma. The two isomers of linalool, (R)-linalool and (S)-linalool, exist in tea leaves. Our study found that (R)-linalool was the minor isomer in nine of Camellia sinensis var. sinensis cultivars. The (R)-linalool synthase of tea plant CsRLIS was identified subsequently. It is a chloroplast-located protein and specifically catalyzes the formation of (R)-linalool in vitro and in vivo. CsRLIS was observed to be a stress-responsive gene and caused the accumulation of internal (R)-linalool during oolong tea manufacture, mechanical wounding, and insect attack. Further study demonstrated that the catalytic efficiency of CsRLIS was much lower than that of (S)-linalool synthase CsSLIS, which might explain the lower (R)-linalool proportion in C. sinensis var. sinensis cultivars. The relative expression levels of CsRLIS and CsSLIS may also affect the (R)-linalool proportions among C. sinensis var. sinensis cultivars. This information will help us understand differential distributions of chiral aroma compounds in tea.
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NEW PHYTOLOGIST
·
2024
·
IF 8.3
Honglian Gu,Jiaxing Li,Dahe Qiao,Mei Li,Yingjie Yao,Hui Xie,Ke-lin Huang,Shengrui Liu,De-Yu Xie,Chaoling Wei,Junyan Zhu
Summary Numerous herbivore-induced plant volatiles (HIPVs) play important roles in plant defense. In tea plants ( Camellia sinensis ), (Z)-3-hexenyl acetate (3-HAC) has been characterized as associated with resistance to herbivores. To date, how tea plants biosynthesize and regulate 3-HAC to resist herbivores remain unclear. Based on transcriptomes assembled from Ectropis obliqua- fed leaves, a cDNA encoding BAHD acyltransferase, namely CsCHAT1 , was highly induced in leaves fed with E. obliqua . Enzymatic assays showed that CsCHAT1 converted (Z)-3-hexenol into 3-HAC. Further suppression of CsCHAT1 expression reduced the accumulation of 3-HAC and lowered the resistance of tea plants to E. obliqua , while 3-HAC replenishment rescued the reduced resistance of CsCHAT1 -silenced tea plants against E. obliqua . Two transcription factors (TFs), CsNAC30 and CsTCP11 , were co-expressed with CsCHAT1 . An integrative approach of biochemistry, DNA–protein interaction, gene silencing, and metabolic profiling revealed that the two TFs positively regulated the expression of CsCHAT1 . The suppression of either one decreased the production of 3-HAC and eliminated the resistance of tea plants to E. obliqua . Notably, the suppression of either one considerably impaired JA-induced 3-HAC biosynthesis in tea plant. The proposed pathway can be targeted for innovative agro-biotechnologies protecting tea plants from damage by E. obliqua .
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PLANT CELL AND ENVIRONMENT
·
2024
·Vol. 47
·期 3
·913-927
·
IF 6
Guanhua Liu,Qian Wang,Hui Chen,Yuxi Wang,Xiaogui Zhou,Demeng Bao,Nuo Wang,Juan Sun,Fuyin Huang,Mei Yang,Han Zhang,Peng Yan,Xin Li,Jiang Shi,Jianyu Fu
Insect-induced plant volatile organic compounds (VOCs) may function as either direct defence molecules to deter insects or indirect defence signals to attract the natural enemies of the invading insects. Tea ( Camellia sinensis L.), an important leaf-based beverage crop, is mainly infested by Ectropis obliqua which causes the most serious damage. Here, we report a mechanistic investigation of tea plant-derived VOCs in an indirect defence mechanism against E. obliqua . Parasitoid wasp Parapanteles hyposidrae , a natural enemy of E. obliqua , showed strong electrophysiological response and selection behaviour towards S -linalool and β-ocimene, two monoterpenes with elevated emission from E. obliqua -damaged tea plants. Larvae frass of E. obliqua , which also released S -linalool and β-ocimene, was found to attract both mated female or male Pa. hyposidrae according to gas chromatography-electroantennogram detection and Y-tube olfactometer assays. In a field setting, both S -linalool and β-ocimene were effective in recruiting both female and male Pa. hyposidrae wasps. To understand the molecular mechanism of monoterpenes-mediated indirect defence in tea plants, two novel monoterpene synthase genes, CsLIS and CsOCS-SCZ , involved in the biosynthesis of S -linalool or β-ocimene, respectively, were identified and biochemically characterised. When the expression of these two genes in tea plants was inhibited by antisense oligodeoxynucleotide, both volatile emission and attraction of wasps were reduced. Furthermore, gene expression analysis suggested that the expression of CsLIS and CsOCS-SCZ is regulated by the jasmonic acid signalling pathway in the tea plant.
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FOOD CHEMISTRY
·
2024
·
IF 8.5
Na Li,Junren Xu,Yiqiao Zhao,Mengmeng Zhao,Zhonghua Liu,Kunbo Wang,Jianan Huang,Mingzhi Zhu
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.
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