FOOD CHEMISTRY
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2021
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IF 7.514
Qi Chen,Mingyue Zhang,Mengxue Chen,Mengru Li,Haiwei Zhang,Pengpeng Song,Tingting An,Pengxiang Yue,Xueling Gao
The three instant dark teas were produced from instant green tea (IGT) by liquid-state fermentations using the microorganisms Eurotium cristatum (EFT), Aspergillus niger (AFT), and sequential inoculation of E. cristatum / A. niger (EAFT), respectively. The volatile compounds of four tea samples were extracted by headspace-solid phase microextraction (HS-SPME) and analyzed using gas chromatography-mass spectrometry (GC-MS) coupled with chemometrics. A total of 97 volatile compounds were tentatively identified to distinguish three fermented instant dark from IGT. Alcohols, acids, esters, ketones, aldehydes, and heterocyclics could be clearly distinguished by principal component analysis (PCA), venn diagram, heatmap analysis and hierarchical cluster analysis (HCA). Descriptive sensory analysis revealed that AFT had a moldy, woody and herbal aroma; EFT showed woody and herbal aroma; and EAFT smelled an herbal, sweet, minty and floral aroma. This study indicates that fermentation using different microorganisms is critical in forming unique aroma characteristics of instant dark teas.
研究领域:
食品科学
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微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL TECHNOLOGY
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2020
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IF 2.213
Xiaolin Li,Yongxing Zhan,Lianghu Su,Yudong Chen,Mei Chen,Longjiang Zhang,Guangyin Zhen,Zhihua Han,Xiaoli Chai
Dark tea-iron nanoparticles (DT-Fe NPs) were prepared using extracts of dark tea leaves as a reducing agent, and further underwent thermal treatment in air. The H2S removal performances of thermal-treated DT-Fe NPs for biogas were further evaluated using a custom-designed fixed-bed reactor (reaction temperature of 250°C, H2S content of 1%). Significant morphology and chemical composition differences were observed when DT-Fe NPs were treated at different temperatures (300–800oC). X-ray diffractometer analysis revealed that a phase transition from γ-Fe2O3 to α-Fe2O3 occurred under heat treatment. When the thermal treatment temperature was 300°C, only α-Fe2O3 was detected. Both α-Fe2O3 and γ-Fe2O3 were present in the sample treated at 400°C. When the thermal treatment temperature was 500–800°C, γ-Fe2O3 in the sample was completely converted to α-Fe2O3. The H2S removal capacity is 14.72 mg H2S/g for DT-Fe NPs without treatment. However, the value increased significantly to 408.30 mg H2S/g after 400°C thermal treatment, which can be explained by the formation of highly active γ-Fe2O3. The reaction product of thermal-treated DT-Fe NPs at 400°C and H2S were further characterized by X-ray diffractometer and X-ray photoelectron spectroscopy. The results showed that it is composed of FeS2 and FeS, in which 72.6% of the sulphur existed as disulphide and 27.4% as monosulphide.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FOOD RESEARCH INTERNATIONAL
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2025
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IF 8
Jia Yu,Yuanjie Wu,Chaoxi Zeng,Haoren Wu,Gaofeng Jia,Jianhui Ye,Si Qin,Zhonghua Liu,Meng Shi
Dark tea has long been recognized for its health-promoting benefits, attributed to its complex phytochemical composition. However, the specific bioactive compounds responsible for these beneficial effects remain inadequately characterized. This study aimed to explore the impact of dark tea water extract (DTE) on digestive enzyme activity, antioxidant capacity, and glucose-lipid balance. DTE was fractioned into four fractions using gel separation, followed by analysis with high-performance liquid chromatography and quasi-targeted metabolomics. The 30 % ethanol elution (EEA) and 50 % ethanol elution (EEB) fractions showed stronger antioxidant and enzyme inhibition effects compared to the whole DTE. The EEA fraction was rich in 5 catechins and 26 additional phytochemicals, while the EEB fraction contained high levels of caffeine, ECG, and 29 other phytochemicals. Notably, significant correlations were observed between quercetin-3,4′-O-di-β-glucopyranoside and 3-(2-Naphthyl)-L-alanine with digestive enzyme inhibition. Cellular studies revealed the ability of EEA and EEB to reduce lipid accumulation, improve glycolipid metabolism, and alleviate oxidative stress by increasing SOD, CAT, and GSH levels while decreasing MDA and ROS in HepG2 cells. Furthermore, 34 flavonoids, 2 alkaloids, 2 terpenes, 2 alcohols and polyols, 2 phenylpropanoids and polyketides, 1 organoheterocyclic compound were directly linked to the antioxidant activity and the modulation of glucose and lipid levels. These findings offer valuable insights into the phytochemical profiles of dark tea and its potential health benefits.
研究领域:
食品科学
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营养学
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药理学
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生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）