Food Chemistry-X
·
2025
·
IF 8.2
Yanxia Xie,Zixi Yang,Yuanmin Zhu,Xuemin Chen,Mengjie Lei,Xiaodi Jin,Wenwen Jin,Chunhua Fu,Longjiang Yu
Tea aroma critically influences consumer preference. Pantoea camelliae Z09, isolated from Yunnan sun-dried green tea, enhances the rose-honey aroma of fermented tea infusion. This study investigated aroma formation during liquid-state fermentation using GC–MS, GC-IMS, and molecular docking. GC–MS and GC-IMS identified 223 and 74 volatile organic compounds (VOCs), respectively, including alcohols, ketones, and esters. Six key aroma-active compounds were identified via relative odor activity value (ROAV), while orthogonal partial least squares discriminant analysis (OPLS-DA) revealed 49 differential VOCs driving aroma evolution. By integrating ROAV, OPLS-DA, abundance analysis, and molecular docking, 29 major VOCs were linked to the rose-honey profile, with phenylethyl alcohol as the dominant contributor. Their binding to olfactory receptors involved noncovalent interaction. A flavor wheel was constructed to visualize the aroma profile. This study is the first to elucidate how bacteria influence the aroma of tea infusion through liquid-state fermentation, offering insights for the development of specialty tea products.
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LWT-FOOD SCIENCE AND TECHNOLOGY
·
2024
·
IF 6
Wen Ouyang,Jingming Ning,Xizhe Zhu,Yongwen Jiang,Jinjin Wang,Haibo Yuan,Jinjie Hua
Fixation is crucial for green tea quality; previous studies were conducted on finished teas and focused on the volatile metabolites of green tea. However, non-volatile metabolites’ (NVMs) evolution and formation mechanisms during fixation remain unclear. Here, fixated tea samples were collected at seven different time points during the green tea fixation stage, the dynamic changes and formation mechanisms of NVMs investigated via ultra-performance liquid chromatography-tandem mass spectrometry and enzymatic activity analyses. The results showed that fixation contained enzymatic activity thermal and non-enzymatic thermal stages. Moreover, 1196 NVMs (10 classes) were detected, and significant NVM variations were observed during the "enzymatic activity thermal" fixation stages, with increasing trends in lipids and amino acids, except alkaloids. Furthermore, 160 common differential NVMs were identified. KEGG analysis revealed that unsaturated fatty acid, linoleic acid phenylpropanoid, and flavonoid metabolism pathways were essential during fixation and influenced green tea aroma, taste, and color formation. These results provide a theoretical basis to regulate green tea fixation technology and enrich the chemical theory of green tea processing.
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Foods
·
2024
·Vol. 13
·期 23
·3977
·
IF 4.7
Bernard Ntezimana,Wenluan Xu,Yuchuan Li,Jingtao Zhou,Sujan Pathak,Yuqiong Chen,Zhi Yu,De Zhang,Dejiang Ni
Withering is one of the major processing steps critical for the quality of black tea. In this study, we investigated the mechanisms underlying the physicochemical changes in metabolites and gene expression during the withering process of black tea using metabolomic and transcriptomic approaches, respectively. Based on gas chromatography/mass spectrometry non-targeted metabolomic approaches (GC-MS) and ultra-high performance liquid chromatograph–tandem mass spectrometry (UHPLC-MS/MS), a total of 76 volatile compounds and 160 non-volatile compounds were identified from tea leaves, respectively. RNA-seq analysis revealed that the number of differentially expressed genes (DEGs) for the comparative combination of withering time (i.e., W4h, W6h, W8h, W10h, and W12h) compared with CK (i.e., fresh leaves) were 3634, 2906, 4127, 5736, and 7650, respectively. The core genes in starch metabolism, namely alpha-amylase (AMY) and beta-amylase (BAM), were upregulated as withering time increased. AMY and BAM contributed to the decomposition of starch to increase the soluble sugars. The content of tea leaf alcohols and aldehydes, which are the vital contributors for greenish aroma, gradually decreased as withering time increased due to the downregulation of associated genes while the compounds related to sweet and fruity characteristics increased due to the upregulated expression of related genes. Most DEGs involved in amino acids were significantly upregulated, leading to the increase in free amino acids content. However, DEGs involved in catechins metabolism were generally downregulated during withering, and resulted in a reduction in catechins content and the accumulation of theaflavins. The same trend was observed in alpha-linolenic acid metabolism-related genes that were downregulated and enhanced the reduction in grassy aroma in black tea. The weighted gene co-expression network analysis (WGCNA) of DEGs showed that one module can be associated with more components and one component can be regulated by various modules. Our findings provide new insights into the quality formation of black tea during the withering process.
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FOOD RESEARCH INTERNATIONAL
·
2025
·
IF 8
Zhijie Huang,Weixiang Xu,Xudong Yang,Mingxi Liu,Lijun Yin,Weibin Bai,Xin Jia
Non-covalent interactions between soybean storage proteins β-conglycinin (7S) and glycinin (11S) and two tea polyphenols, catechin and epigallocatechin-3-gallate (EGCG), were examined to elucidate their effects on protein conformation, stability, digestibility, allergenicity, and antioxidant capacity. Due to its smaller molecular size, catechin more easily penetrated the hydrophobic cores of proteins, yielding higher binding stoichiometry and concentration-dependent aggregation. At 4 mM, extensive aggregation masked proteolytic cleavage sites, reducing gastrointestinal digestibility by 7.3 % for 7S and 15.1 % for 11S. In contrast, EGCG, with an additional galloyl moiety and a denser hydroxyl network, interacted with proteins through synergistic hydrogen bonding, π–π stacking, and hydrophobic forces. It produced more stable supramolecular complexes with much larger diameters (462.2 ± 6.8 nm for 11S-EGCG, versus 30.3 ± 1.5 nm for native 11S), and lowered IgE-binding capacity by approximately 19.5–38.7 %, probably through epitope masking and surface-charge changes. For both polyphenols, binding significantly decreased solvent accessibility of hydrophobic regions, reorganized secondary structure (α-helix loss and β-sheet gain), and markedly enhanced intrinsic antioxidant capacity. These findings demonstrate that selecting an appropriate polyphenol type and dose can simultaneously confer hypoallergenic potential, controlled digestibility, and elevated antioxidant function. These findings highlight the potential of non-covalent protein-polyphenol assemblies to develop plant-based foods and nutraceuticals with improved health benefits.
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MICROCHEMICAL JOURNAL
·
2018
·
IF 2.746
Kai Hu,Jingyi Qiao,Xiangxiang Wu,Huaixia Yang,Yanjie Huang,Shusheng Zhang
A novel magnetic sorbent has been synthesized by co-polymerization of calixarene ionic liquid and mercaptan-modified Fe 3 O 4 particles. This material was used as a sorbent for dispersive solid phase extraction of trace-level flavonoids in the samples of bottled fruit juice and green tea without other pre-treatments. The experimental parameters were investigated and optimized. Coupled with high performance liquid chromatography, an analytical method was established and successfully applied to the determination of flavonoids in these beverages. The proposed method showed good linearity for the analytes with a correlation coefficient ( r ) > 0.9982, and detection limits for the flavonoids ranged 0.15–0.75 ng mL −1 were achieved. The proposed method has been used successfully to determine flavonoids in bottled fruit juice and green tea samples with satisfactory recoveries of 92.5–104.8% and relative standard deviations ≤ 5.2%. The results suggest that poly(calixarene ionic liquid) modified Fe 3 O 4 nanoparticles can be used in the extraction of flavonoids in beverage samples.
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INORGANIC CHEMISTRY COMMUNICATIONS
·
2021
·
IF 2.495
Ziyang He,Jiaxin Cheng,Wenfeng Yan,Wei Long,Hui Ouyang,Xin Hu,Meiying Liu,Naigen Zhou,Xiaoyong Zhang,Yen Wei
In this work, we developed a simple, economical and forthright strategy for synthesis of polyethylene glycol functionalized CQDs (PEG@CQDs) through a one-pot thiol-ene click reaction using mercapto polyethylene glycol and green tea ash. These PEG@CQDs displayed excellent water dispersibility and intense blue-green fluorescence. The fluorescence emission wavelengths of these PEG@CQDs are depended on the excitation wavelengths. Furthermore, cell viability and cell internalization of PEG@CQDs were examined by MTT assay and confocal laser scanning microscopy. The results demonstrated that PEG@CQDs showed low cytotoxicity towards HepG2 cells and strong green fluorescence could be detected after HepG2 cells were excited with a 405 nm laser. All the above results demonstrated that PEG@CQDs possess small size, high water dispersibility and fluorescence properties and could be potentially utilized for cell fluorescent imaging. We hope the method will provide some novel ideas for preparation of functional CQDs and inspired the biomedical applications of these functional CQDs.
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International Journal of Electrochemical Science
·
2023
·
IF 1.5
Yanju Wu,Jianyao Kou,Lijie Wang,Long Cheng,Kui Lu
In this work, Langmuir-Blodgett (LB) technique was proposed to fabricate the homogeneous and controlled films of Nafion-nitrogen doped carbon nanotubes (Nafion-NCNTs). Microstructure and electrochemical performance of LB films of Nafion-NCNTs was characterized by atomic force microscopy (AFM) images, scanning electron microscopy (SEM) images and electrochemical experiments. Moreover, the LB film of Nafion-NCNTs was transferred to the surface of glassy carbon (GC) electrode to fabricate the electrochemical sensor to apply for determination of caffeine. Electrochemical experiments show that the LB films of Nafion-NCNTs modified GC electrode can effectively increase electrochemical response of caffeine. Under the optimum conditions, the oxidation peak current of caffeine was proportional to its concentration in the range of 8.0 × 10 -8 ~ 4.0 x 10 -6 mol L -1 , with a detection limit of 2.0 × 10 -8 mol L -1 . And the modified GC electrode showed excellent selectivity, good stability and repeatability. It also was successfully used for determination of the content of caffeine in tea samples.
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高影响因子
JOURNAL OF RAMAN SPECTROSCOPY
·
2018
·Vol. 50
·期 3
·322-329
·
IF 2.879
Qing Liu,Zeng-Ping Chen,Cai-Xia Shi,Yao Chen,Ru-Qin Yu
A surface-enhanced Raman spectroscopy (SERS) method for the quantification of Co 2+ in Chinese tea was developed in this contribution. SERS-enhancing substrates with a high selectivity for Co 2+ were prepared by attaching 2-(bis (pyridin-2-ylmethyl)amino)ethane-1-thiol onto the surfaces of Ag nanoparticles. A calibration model based on the spectral shape deformation quantitative theory was derived to address the poor reproducibility problem in SERS assays due to the practical impossibility in controlling the number and distribution of “hot spots” on or close to the surface of enhancing substrates. The proposed SERS platform was applied to the quantification of Co 2+ in Chinese tea samples and achieved quite satisfactory quantitative results. The average relative deviation between the quantitative results of the proposed SERS platform and those of inductively coupled plasma mass spectrometry was about 6.0%. It is therefore reasonable to expect that the proposed SERS platform can be a competitive alternative for the quantification of Co 2+ in food samples.
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FOOD CHEMISTRY
·
2024
·
IF 8.5
Hongling Wang,Xianghui Qi,Song Gao,Guoshi Kan,Lkhagvasuren Damdindorj,Yingfeng An,Fuping Lu
Herein, a novel multifunctional enzyme β-glucosidase/xylanase/feruloyl esterase (GXF) was constructed by fusion of β-glucosidase and bifunctional xylanase/feruloyl esterase. The activities of β-glucosidase, xylanase, feruloyl esterase and acetyl xylan esterase displayed by GXF were 67.18 %, 49.54 %, 38.92 % and 23.54 %, respectively, higher than that of the corresponding single functional enzymes. Moreover, the GXF performed better in enhancing aroma and quality of Longjing tea than the single functional enzymes and their mixtures. After treatment with GXF , the grassy and floral odors of tea infusion were significantly improved. Moreover, GXF treatment could improve concentrations of flavonoid aglycones of myricetin, kaempferol and quercetin by 68.1-, 81.42- and 77.39-fold, respectively. In addition, GXF could accelerate the release of reducing sugars, ferulic acid and xylo -oligosaccharides by 9.48-, 8.25- and 4.11-fold, respectively. This multifunctional enzyme may have potential applications in other fields such as food production and biomass degradation.
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Food Chemistry-X
·
2024
·
IF 6.5
Leyin Cui,Xin Wang,Changxu He,Zhengquan Liu,Jin Liang
The effect of puffing treatment on the volatile components of green tea has been studied. A total of 155 volatile compounds were identified by using HS-SPME and SPE extraction methods, combined with gas chromatography–mass spectrometry (GC–MS). The total concentration of volatile compounds in puffed green tea increased by 2.25 times compared to that in before puffing. 12 key volatile compounds in green tea were identified before and after puffing using a combination of multivariate statistical analysis, GC-O, AEDA dilution analysis, and relative odor activity value (rOAV). The puffing process generates the Maillard reaction, where sugars react with amino acids to produce Maillard reaction products (such as pyrazine, pyrrole, furan, and their derivatives), giving them a unique baking aroma. The proportion of these compounds in the total volatile matter increased. The research results provided guidance and a theoretical basis for improving the aroma processing of green tea.
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JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2025
·
IF 4.6
Zhihong Huang,Lu Wang,Xinjie Li,Bingjun Lu,Yuli Lin,Bo Fu,Chiqun Shan,Xinxin Tang,Pei Sung Toh,Shaoyou Lu
With the widespread use of plastic products, phthalates (PAEs), as common plasticizers, have become a significant contributor to environmental pollution. PAEs can migrate to tea leaf during cultivation, processing, and packaging, and can be released into the tea infusion during brewing, posing potential risks to human health. A total of 220 tea samples from four major tea-producing regions in China were collected and analyzed for the concentrations of 13 PAEs in tea leaves and tea infusions. PAEs were present in all tea samples at concentrations ranging from 504.4 to 6177.0 ng/g, with dibutyl phthalate (DBP) contributing the most. Dark tea and tea from the eastern coast and southern regions of China were the most contaminated. The brewing experiments indicated that PAEs could migrate into tea infusions, with concentrations ranging from 0 to 77.4 ng/mL, showing the highest transfer rates during the second and third brews. The health risk assessment results revealed that PAEs posed low noncarcinogenic and carcinogenic risks through tea consumption, but risk levels were significantly higher in children than in adults. This indicates the necessity for giving children more attention. We suggest stricter environmental protection measures during tea cultivation, processing, and packaging to safeguard public health.
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Food & Function
·
2021
·Vol. 13
·期 2
·806-824
·
IF 5.396
Yujiao Sun,Fan Wang,Yang Liu,Yuye An,Dawei Chang,Jiankang Wang,Fei Xia,Ning Liu,Xuefeng Chen,Yungang Cao
In the present study, the purpose is to compare the effect of water extraction and alkali-assisted extraction on the structural characteristics and immunomodulatory activity of polysaccharides from Fuzhuan brick tea (FBTPs). The results indicated that water-extracted FBTPs (W-FBTPs) and alkali-extracted FBTPs (A-FBTPs) had similar molecular weights but different monosaccharide compositions, of which A-FBTPs had a higher yield and uronic acid groups corresponding to galacturonic acid (GalA). Moreover, A-FBTPs had stronger ability to promote phagocytic capacity, acid phosphatase activity and nitric oxide (NO) secretion in macrophages in vitro. In the in vivo study, A-FBTPs exhibited a promising effect to adjust the immune imbalance by enhancing the body features, antioxidant activities, immune response and intestinal mucosal barrier in cytoxan (CTX)-induced immunosuppressive mice. Besides, A-FBTP supplementation effectively improved CTX-induced gut microbiota dysbiosis, including promoting the abundance of beneficial bacteria (e.g., Lactobacillus) and short chain fatty acid (SCFA)-producing bacteria (e.g., Lachnospiraceae, Prevotellaceae and Ruminococcaceae), along with reducing the growth of potentially pathogenic microbes (e.g., Desulfovibrionaceae and Helicobacter). These findings suggested that alkaline extraction might be a promising way to obtain high-quality acidic polysaccharides from Fuzhuan brick tea (FBT), and A-FBTPs could be developed as novel potential prebiotics and immunomodulators for further application in food formulations.
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