FOOD CONTROL
·
2023
·
IF 6
Lingli Sun,Suwan Zhang,Qiuhua Li,Erdong Yuan,Ruohong Chen,Feiteng Yan,Xingfei Lai,Zhenbiao Zhang,Zhongzheng Chen,Qian Li,Shili Sun
Oolong tea have better richness, sweetness and throat after a certain time of storage. These variations in taste and quality are closely related to changes in the composition of oolong tea during storage, however, the metabolic profiles of oolong tea during storage have not been reported so far. Therefore, we evaluated the differences in taste quality of oolong tea in four storage years (1991, 2001, 2011 and 2021) by using electronic tongue technology, and the results showed that the bitterness, astringency and richness of oolong tea are significantly reduced during storage, but the acidity have the opposite trend, while the sweetness did not trend, with the least sweetness in 2011 and no difference in sweetness in the rest of the years. We further explored the metabolites contributing to the differences in taste quality of Dancong tea in four storage years (1991, 2001, 2011 and 2021) using metabolomics technique and the results showed that a total of 1245 metabolites were detected, of which nine were taste characteristic components of Aged Dancong tea. Dancong tea mainly increased azelaic acid, suberic acid, 2-hydroxyphenylacetic acid and other sour characteristic components in aged tea by regulating phenylalanine metabolism, metabolic pathways, and pyrimidine metabolism and mainly decreased benzamide, propyl 4-hydroxybenzoate, pyrrole-2-carboxylic acid and other bitterness and astringency characteristic components by regulating arginine and proline metabolism, flavonoid biosynthesis, biosynthesis of secondary metabolites, which enhanced the sour and umami of aged tea and reduced its bitterness and astringency. This study provides theoretical support for the quality of aged oolong tea, with a view to providing guidance for the storage of oolong tea.
研究领域:
食品科学
·
代谢组学
·
茶叶研究
✓ 已验证
产品关联
DOI
高影响因子
FOOD SCIENCE AND BIOTECHNOLOGY
·
2019
·Vol. 28
·期 5
·1349-1358
·
IF 0.888
Lin Jie,Shi Yuanxu,Dong Chunwang,Wang Xiaochang
The perceived aroma of oolong tea is primarily and directly affected by its infusion matrix, and the release persistence of headspace volatiles can better illustrate the persistent aroma. Headspace solid phase microextraction coupled with gas chromatography–mass spectrometry was performed to analyze the headspace constituents of oolong tea. The presence of the infusion matrix seemed to prevent the headspace release of certain odorants. The release of indole, nerolidol, and α -farnesene was also remarkably enhanced or depressed (2.70, 1.56, and 0.69-fold in tea infusion versus in dry leaves). Moreover, the amount of volatile species gradually decreased with increased water ratio. Eight odorants were determined to be stable and persistent during continuous infusion, whereas six were determined to be less persistent (gradually decreased or stopped releasing). The volatile dilution test further confirmed the persistent release of nerolidol.
研究领域:
食品科学
·
植物化学
✓ 已验证
DOI
PubMed
高影响因子
PLANT FOODS FOR HUMAN NUTRITION
·
2009
·Vol. 64
·期 4
·293-296
·
IF 1.69
Chen Yulong,Duan Jun,Yang Shaoyu,Yang En,Jiang Yuming
Oolong tea is one of the most popular beverages due to the presence of significant amount of catechins. Experiments were conducted to investigate the effect of girdling treatment on levels of catechins in fresh tea leaf related to quality of the ‘Huang Zhi Xiang’ Oolong tea ( Camellia sinensis ). The variations in the levels of catechins in fresh tea leaf and the quality score (QS) of the ‘Huang Zhi Xiang’ Oolong tea were examined. The study demonstrated that girdling treatment increased significantly the levels of (−)-epicatechin, (−)-epigallocatechin, (−)-epigallocatechin gallate, (−)-epicatechin gallate, total catechins, simple catechin, and catechin gallate present in fresh leaf of tea trees. Furthermore, the girdling treatment improved significantly the quality of the ‘Huang Zhi Xiang’ Oolong tea. Thus, it was suggested that application of girdling treatment could be an effective agronomic practice to increase the quality of ‘Huang Zhi Xiang’ Oolong tea.
研究领域:
园艺学
·
植物生理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2023
·
IF 8.8
Xiaohui Wang,Jingjie Cao,Xin Cheng,Xuyang Liu,Wenfeng Zhu,Yan Li,Xiaochun Wan,Shengkeng Chen,Linlin Liu
Solar withering is essential for the aroma formation of oolong tea, but due to the rainy and humid weather in plantation areas, solar withering became insufficient which seriously limits high-grade oolong tea production. This study aims to investigate ultraviolet B (UV-B) effects on the aroma characteristics of oolong tea and its feasibility in improving tea aroma quality. Sensory evaluation, odorant quantitation, and aroma characteristic analysis suggested UV-B application during the aeration process provided similar effects as solar withering in improving the aroma quality of oolong tea. UV-B application significantly increased fruity and floral odorants (4-hexanolide, α -farnesene, and β -ocimene by 44%, 74%, and 37%, respectively), and decreased green and fatty odorants (hexanal, ( E )-2-octenal, and ( Z )-4-heptenal by 42%, 45%, and 27%, respectively). These indicate UV-B is crucial for the flowery and fruity aroma formation of oolong tea, which can be potentially applied to oolong tea production, especially under unsunny weather.
研究领域:
食品科学
·
植物生理学
✓ 已验证
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2024
·
IF 8.5
Qi Lin,Cheng Peng,Kunpeng Yu,Yanling Lin,Yongquan Xu,Lijun Li,Hui Ni,Feng Chen
The β-glucosidases known to improve tea aroma are all mesothermal enzymes, limiting their use under brewing conditions. Based on the properties analysis and molecular docking, the thermostable β-glucosidase (TPG) from Thermotoga petrophlia showed potential to enhance tea aroma. Treatment by recombinant TPG at 90 °C, the floral, sweet and grassy notes of instant Oolong tea were increased, while the roasted, caramel and woody notes were decreased. The improved floral, sweet and grassy notes were related to increase releasing of benzyl alcohol (floral), geraniol (floral), (Z)-3-hexen-1-ol (grassy), benzaldehyde (sweet) and 1-hexanol (grassy) by TPG hydrolyzing of (Z)-3-hexenyl-β-D-glucopyranoside, hexanyl-β-D-glucopyranoside (HGP), benzyl-β-D-glucopyranoside, prunasin and geranyl-β-D-glucopyranoside (GGP), respectively. Although the catalytic efficiency of TGP to GGP was about twice that to HGP, HPG was more competitive than GGP when they mixed. Combined with microstructure analysis, the structure-function relationship of TPG-influencing tea aroma were understood. This study provided the method of how to mining new function of characterized β-glucosidases, as well as a theoretical basis for the development of new tea products.
研究领域:
食品科学
·
酶学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2019
·
IF 5.399
Xi Chen,Mengshi Lin,Lin Sun,Taotao Xu,Keqiang Lai,Meizhen Huang,Hetong Lin
The contamination of pesticide residues in Oolong tea has raised much concern in recent years. The objective of this study was to synthesize gold nanoparticles (AuNPs) and develop surface-enhanced Raman spectroscopy (SERS) methods for detection and quantification of pesticides in Oolong tea. Facile synthesis of spherical and monodispersed AuNPs with an average diameter of 15 nm was achieved, which induced strong electromagnetic fields in SERS analysis. AuNP substrates were employed for rapid detection and quantification of carbendazim in Tieguanyin Oolong tea. Partial least squares (PLS) analysis and leave-one-out cross validation were utilized in spectral data analysis. The PLS results for Oolong tea samples were obtained: R value = 0.964; the detection limit = 100 μg/kg. These results demonstrate that SERS coupled with gold nanoparticle substrate is a simple, rapid, and sensitive analytical tool for measurement and quantification of carbendazim residues in Oolong tea.
研究领域:
分析化学
·
食品安全
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
·
2018
·Vol. 54
·期 2
·490-498
·
IF 2.383
Zhou-Tao Fang,Chu-Jun Song,Hai-Rong Xu,Jian-Hui Ye
Summary Flavonol glycosides with low thresholds are important flavour substances in tea leaves. This study monitored the dynamic changes in flavonol glycosides during the production of different teas. The fresh leaves of cv. Fudingdabaicha with 15.77 mg g −1 of total flavonol glycosides (TFG) were respectively processed into green, yellow, white, oolong and black teas. A reduction of TFG was observed for different teas, amongst which black tea contained the lowest level of TFG (9.83 mg g −1 ), followed by oolong tea (11.96 mg g −1 ), while green, yellow and white teas contained similar levels of TFG (~13.70 mg g −1 ). Fixation was crucial to maintain the stability of flavonol glycosides due to its inactivation effect on enzymes at high temperature. Principal component analysis results indicated that flavonol glycosides were vulnerable to fermentation, and the stabilities of flavonol glycosides were related with aglycone and glycoside moiety.
研究领域:
植物化学
·
食品科学
·
茶叶加工学
✓ 已验证
产品关联
DOI
高影响因子
FOOD CHEMISTRY
·
2023
·
IF 8.8
Yanqun Xu,Jieqiong Wang,Ziqing Wu,Jing Huang,Zhenbiao Li,Jiayi Xu,Dan Long,Tian Ye,Gennv Wang,Junfeng Yin,Zisheng Luo,Yongquan Xu
Chinese Oolong tea is widely known for its intricate aroma. However, the degradation of volatile organic compounds (VOCs) poses significant challenges for the tea products. In this study, glutathione (GSH) has an excellent preservation effect on VOCs in both the VOCs extract and the tea infusion during storage, specifically slowing the degradation of hexanal (by 66.39% and 35.09%) and heptanal (by 67.46% and 63.50%). Additionally, the addition of GSH maintained higher levels of active ingredients in tea infusion, including epigallocatechin, procyanidin B1, glutamic acid, and L-(+)-arginine, with respective increases of 184.09, 2.92, 4.10, and 6.35 times. The sulfhydryl group of GSH formed a covalent bond with hexanal and 2-methylbutanal, therefore improving the stability of VOCs. These findings provided a valuable insight for developing effective VOC preservation techniques for water-based tea products.
研究领域:
食品科学
·
植物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Food Chemistry-X
·
2025
·
IF 8.2
Jirui Kun,Zhengfei Luo,Menghan Gong,Qing Meng,Yingjuan Chen,Lianyu Yuan,Yiwei Weng,Jin Sun,Hongwei Dai,Huarong Tong
The cup aroma (CA), a lingering scent in the empty cup after tea consumption, is important to sensory evaluation and overall experience; however, the compounds contributing to the distinct floral honey-like CA of Fenghuang Dancong oolong tea (FHDC) remain unknown. CA of FHDC had strong nectar, ginger-like, and floral, while the tea infusion (TA) was characterized by tropical fruit, sweet, and floral notes. OAV and GC-O analyses revealed that esters, aldehydes, and alcohols were major contributors to the CA, with distinct variations in the volatile compound profiles between TA and CA. Twenty-one and 17 aroma active compounds were identified in TA and CA, respectively. GC-O analysis of the CA revealed 17 key odorants, among which α-ionone, geraniol, 4-methylpent-3-en-2-one, ( E )-2-nonenal, heptanal, limonene, linalool, and ( Z )-2-penten-1-ol exhibited intensities of 3 or higher. An aroma recombination experiments confirmed the identification of 17 key odorants, successfully replicating the original floral honey-like cup aroma.
研究领域:
食品科学
·
茶叶化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Food Chemistry-X
·
2022
·
IF 6.443
Ding-Tao Wu,Wen Liu,Qin Yuan,Ren-You Gan,Yi-Chen Hu,Sheng-Peng Wang,Liang Zou
In this study, dynamic variations in physicochemical characteristics of polysaccharides from ‘ Wuyi rock’ tea (WYP) at different simulated digestion and fecal fermentation stages in vitro were studied. Results revealed that physicochemical characteristics of WYP were slightly altered after the simulated digestion in vitro , and its digestibility was about 8.38%. Conversely, physicochemical characteristics of the indigestible WYP, including reducing sugar, chemical composition, constituent monosaccharide, molecular weight, and FT-IR spectrum, were obviously altered after the fecal fermentation in vitro , and its fermentability was about 42.18%. Notably, the indigestible WYP could remarkably modulate the microbial composition via promoting the proliferation of profitable intestinal microbes, such as Bacteroides , Lactococcus , and Bifidobacterium . Moreover, it could also enhance the generation of short-chain fatty acids. The results showed that WYP was slightly digested in the gastrointestinal tract in vitro , but could be obviously utilized by intestinal microbiota, and might possess the potential to improve intestinal health.
研究领域:
食品科学
·
微生物学
·
营养学
✓ 已验证
DOI
高影响因子
FOOD CHEMISTRY
·
2009
·
IF 2.696
Yulong Chen,Yueming Jiang,Jun Duan,John Shi,Sophia Xue,Yukio Kakuda
The variations in the contents of catechins and phenolic compounds in relation to the quality scores (QS) and taste scores (TS) in the ‘ Huang Zhi Xiang ’ Oolong tea grown in different seasons and at different altitudes were determined. The study demonstrated that the contents of (−)-epigallocatechin gallate (EGCG), catechin gallate (CG), and total catechins (TC) in the Oolong teas grown at a high altitude were significantly higher than those grown at a low altitude. Furthermore, the contents of EGCG, CG, and TC in the autumn tea were significantly higher than those from the spring tea grown at a low altitude. However, no significant differences in the contents of EGCG, CG, and TC were observed between the spring and autumn teas grown at a high altitude. In addition, the contents of (−)-epigallocatechin (EGC), (+)-catechin (C), (−)-gallocatechin (GC), and simple catechins (SC) in the spring tea leaves were significantly higher than those in the autumn tea leaves grown at a low altitude, but they were not significantly different from those in the autumn tea leaves grown at a high altitude. The contents of EGCG, CG, and TC in the Oolong teas were positively and significantly correlated to the taste score (TS) and quality score (QS) of the Oolong tea. Thus, the contents of EGCG, CG, and TC could be the important quality parameters of the ‘ Huang Zhi Xiang ’ Oolong tea. This work suggested that the production of the ‘ Huang Zhi Xiang ’ Oolong tea grown at low altitudes should utilize the autumn tea leaves while the production of Oolong tea grown at high altitudes can use both the spring and autumn tea leaves.
研究领域:
植物学
·
食品科学
·
农业科学
✓ 已验证
DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2015
·
IF 2.912
Jiadong Gui,Xiumin Fu,Ying Zhou,Tsuyoshi Katsuno,Xin Mei,Rufang Deng,Xinlan Xu,Linyun Zhang,Fang Dong,Naoharu Watanabe,Ziyin Yang
It was generally thought that aroma of oolong tea resulted from hydrolysis of glycosidically bound volatiles (GBVs). In this study, most GBVs showed no reduction during the oolong tea manufacturing process. β-Glycosidases either at protein or gene level were not activated during the manufacturing process. Subcellular localization of β-primeverosidase provided evidence that β-primeverosidase was located in the leaf cell wall. The cell wall remained intact during the enzyme-active manufacturing process. After the leaf cell disruption, GBV content was reduced. These findings reveal that, during the enzyme-active process of oolong tea, nondisruption of the leaf cell walls resulted in impossibility of interaction of GBVs and β-glycosidases. Indole, jasmine lactone, and trans-nerolidol were characteristic volatiles produced from the manufacturing process. Interestingly, the contents of the three volatiles was reduced after the leaf cell disruption, suggesting that mechanical damage with the cell disruption, which is similar to black tea manufacturing, did not induce accumulation of the three volatiles. In addition, 11 volatiles with flavor dilution factor ≥44 were identified as relatively potent odorants in the oolong tea. These results suggest that enzymatic hydrolysis of GBVs was not involved in the formation of volatiles of oolong tea, and some characteristic volatiles with potent odorants were produced from the manufacturing process.
研究领域:
食品科学
·
植物学
·
生物化学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）