Foods
·
2025
·Vol. 15
·期 1
·110
·
IF 5.1
Zhen Zeng,Qiyun Zhang,Lijia Zhang,Baichuan Hu,Xinyue Wen,Zihan Wang,Wenjuan Wu,Yuntao Liu
This study systematically examines the effects of processing methods (green vs. black tea) and preparation techniques (brewing vs. decoction) on the flavor and functional composition of Chinese sweet tea ( Lithocarpus litseifolius ). Fermentation degree and extraction temperature were found to significantly influence polyphenol bioavailability, with green tea exhibiting the highest polyphenol and flavonoid contents (144.51 mg/g and 88.97 mg/g, respectively), while black tea showed an approximately 40% reduction in catechin levels due to oxidative polymerization. During in vitro simulated digestion, green tea maintained strong antioxidant activity despite its stronger bitter–astringent taste. Notably, in vitro fecal fermentation experiments demonstrated that sweet tea significantly promoted short-chain fatty acid (SCFA) production and modulated gut microbiota composition (with a 3.2-fold increase in acetate content in the black-tea decoction group). Black tea particularly enhanced beneficial genera (Roseburia and Coprococcus) after 24 h fermentation ( p < 0.05) and exhibited superior prebiotic properties. Principal coordinate analysis confirmed there were significant structural differences in microbial communities among the treatment groups. This study is the first to reveal that processing methods regulate the prebiotic efficacy of sweet tea by modulating the bioaccessibility of active compounds, providing a theoretical foundation for the development of functional sweet tea products.
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FOOD CHEMISTRY
·
2018
·
IF 4.946
Xiangyang Guo,Chuankui Song,Chi-Tang Ho,Xiaochun Wan
l -Theanine, the most abundant amino acid in tea, is widely believed to be associated with the tea taste, however, its contribution to the formation of tea aroma is still unknown. Volatiles were determined and nitrogen-containing compounds formed during manufacturing processes were quantified. Lower levels of total sugar and l -theanine were detected in the Oolong tea product undergoing full fire processing (FFOT) suggesting that l -theanine probably involved in the volatile formation during manufacturing processes. Methylpyrazine and 2,5-dimethylpyrazine, two newly formed compounds in FFOT, together with other volatiles were successfully detected in a model thermal reaction of d -glucose and l -theanine (GT-MTR) but not detectable in thermal reactions with single d -glucose (G-MTR) or l -theanine (T-MTR). The concentration of 2,5-dimethylpyrazine increased significantly by adding additional l -theanine to 2nd roasted tea. Our study demonstrated that l -theanine, at least partly, contributed to the formation of 2,5-dimethylpyrazine, a key roasted peanutty flavor in Oolong tea.
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CyTA-Journal of Food
·
2018
·
IF 1.371
Yingmei Wu,Wenfeng Li,Yalong Lu,Qiu Wu,Xingbin Yang
High fructose (HF) ingestion is a common risk factor for the development of nonalcoholic fatty liver disease (NAFLD), which has become a serious health problem. The underlying mechanism of HF-induced NAFLD needs to be further understood and an effective prevention needs to be established urgently. Gas chromatography-mass spectrometer-based metabonomic method was employed to characterize the serum metabolic profile of HF-induced NAFLD in mice. β-Hydroxybutyric acid, elaidic acid and oleic acid that contributed to energy and lipid metabolism were confirmed as potential biomarkers for HF-induced NAFLD. With these changed metabolic pathways as possible drug targets, different administrations revealed that co-administration of stachyose and tea polyphenols was a more effective method than treatment of stachyose or tea polyphenols alone for preventing HF-induced negative changes of metabolic pathways in mice. These findings suggest that β-hydroxybutyric acid, elaidic acid and oleic acid are potential biomarkers in HF-induced NAFLD, and co-administration is a novel preventive strategy.
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Food Biophysics
·
2016
·Vol. 12
·期 1
·78-87
·
IF 1.605
Wu Zhibing,Shen Liangliang,Han Qingguo,Lu Jun,Tang Haifeng,Xu Xu,Xu Hong,Huang Fengwen,Xie Jiangfeng,He Zhendan,Zeng Zheling,Hu Zhangli
Ligupurpuroside A is a glycoside extracted from Ku-Ding tea. As extracts from Ku-Ding tea exhibit anti-inflammatory property, we hypothesize that Ligupurpuroside A may be an active compound which inhibits trypsin activity during the anti-inflammatory process. The mechanism and nature of inhibition of trypsin by Ligupurpuroside A have been studied by multi-spectroscopic method, enzyme-activity assay and molecular docking. Enzyme activity assay reveals that Ligupurpuroside A significantly inhibits the activity of trypsin through a competitive manner with an IC 50 value of 3.08 × 10 −3 mol L −1 . Fluorescence titration together with thermodynamic analysis indicate that a Ligupurpuroside A-trypsin complex is formed, and that hydrophobic force and hydrogen bonding are the main forces stabilizing the complex. UV-vis absorption, synchronous fluorescence and circular dichroism spectra show that the interaction between Ligupurpuroside A and trypsin induces conformational changes of trypsin with a decrease in the contents of α-helix and β-sheet. Finally, molecular docking further suggests that Ligupurpuroside A molecule binds within the active pocket of trypsin via hydrophobic force and hydrogen bond. Results from this study of the interaction of trypsin with its natural inhibitor should be useful to minimize the antinutritional effects and make full use of tea extracts in the food industry, and be also helpful to the design of the drugs for the diseases related to overexpression of trypsin.
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Journal of Environmental Chemical Engineering
·
2021
·
IF 5.909
Zheng-Wei Ma,Kai-Ning Zhang,Zhi-Jin Zou,Qiu-Feng Lü
A novel activated carbon (C CH-TS ) derived from chitosan hydrogel (CH) coated tea saponin (TS) was prepared to investigate its removal performance for methylene blue (MB). C CH-TS was characterized by thermogravimetric analysis , field-emission scanning electron microscope , fourier transform infrared spectroscopy , X-ray diffraction, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller, and zeta potential analysis. The results showed that C CH-TS had a high specific area of 3504 m 2 /g with a large pore volume of 6.03 m 3 /g. In the batch mode adsorption experiments, the effects of initial pH values, adsorbent concentration, initial MB concentration and contact time, and adsorption temperature on the adsorption performance of C CH-TS for MB were studied. The experimental results were fitted by pseudo-first-order kinetic, pseudo-second-order kinetic and intra-particle diffusion models. Furthermore, Langmuir, Freundlich and Temkin isotherms were employed to analyze the equilibrium adsorption data. It was found that these data were fitted to Langmuir isotherm best with a maximum adsorption capacity of 604.10 mg/g, while pseudo-second-order kinetic model could describe the adsorption process more accurately. Thermodynamic analysis implied that the adsorption process was spontaneous and exothermic. Therefore, a facile one-step route to preparation of activated carbon with a high specific area and efficient dye removal ability was achieved.
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LWT-FOOD SCIENCE AND TECHNOLOGY
·
2020
·
IF 4.006
Ruifei Wang,Xinyi Hu,Addo Keren Agyekumwaa,Xiaofeng Li,Xinglong Xiao,Yigang Yu
Fresh fish are highly perishable because their high content of protein and unsaturated fatty acids are easily oxidized and/or degraded under the influence of bacteria and the external environment. In this study, four natural preservatives (phenyllactic acid, kojic acid , tea polyphenols and thymol) were initially screened for antimicrobial activity against spoilage bacteria commonly found in fish by in vitro antibacterial tests. The results suggested that kojic acid (KA) and tea polyphenols (TP) exhibited a strong synergistic antibacterial effect against spoilage bacteria. Hence, the effects of KA and/or TP on the preservation of refrigerated sea bass ( Lateolabrax japonicus ) fillets after soaking treatments were determined. Changes in physicochemical parameters, indexes of fish freshness and microbial enumeration were examined. KA, TP and KA-TP treatments were effective in inhibiting bacterial growth and delaying lipid oxidation in fish flesh, resulting in lower TVB-N and TBARS than the control. Meanwhile, the freshness and physical qualities (color and texture) of fish fillets were also stabilized by the three treatments. Moreover, the KA-TP treatment showed the best effect on refrigerated fish preservation among the three treatments and extended the shelf-life by 5–6 days, suggesting that KA-TP have the potential to become a compound preservative for aquatic products.
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FOOD CHEMISTRY
·
2021
·
IF 7.514
Wanjun Ma,Yali Shi,Gaozhong Yang,Jiang Shi,Junpeng Ji,Yue Zhang,Jiatong Wang,Qunhua Peng,Zhi Lin,Haipeng Lv
In order to investigate the hypolipidaemic and antioxidant effects of various dark teas produced from different post-fermentation using the same raw material, a hyperlipidaemia zebrafish model combined with binding bile salts assay and antioxidant assays were performed in this study. Results showed that the hypolipidaemic effect of dark tea extracts increased significantly ( p < 0.05) while the antioxidant ability decreased sharply compared with raw material. Particularly, Liupao tea (50%) and Pu-erh tea (48%) showed promising hypolipidaemic potential; however, the antioxidant capacity of Pu-erh tea decreased (31–49%) most dramatically. Besides, the levels of total polyphenols and catechins decreased sharply, but theabrownin, gallic acid, and caffeine increased significantly after post-fermentation. Moreover, the potential mechanisms of regulating hyperlipidaemia by dark tea extracts were discussed. These results suggest that microbial fermentation significantly affects the bioactivity of dark teas, and provide theoretical basis for processing and improving of dark tea products for hyperlipidaemia therapy.
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CHEMISTRY & BIODIVERSITY
·
2016
·Vol. 13
·期 11
·1573-1583
·
IF 1.444
Bao Yu,Dan Zhang,Xue-Wei Yan,Jian-Wei Wang,Ling Yao,Li-Hong Tan,Sheng-Ping Zhao,Na Li,Wei-Guo Cao
In this study, volatile oils of six Hawk tea varieties were studied for their chemical composition, antioxidant and antimicrobial activities to screen the most suitable botanical origins of Hawk tea. A total of 72 components were separated and identified from the six oils. The major constituents of the volatile oils were: α -pinene, camphene, limonene, 1,8-cineole, linalool, cis -nerolidol, and germacrene B. Moreover, the volatile oils were evaluated for antioxidant potential and antimicrobial activities. The results showed that all volatile oils exhibited acceptable antioxidant and antimicrobial activities, which suggested that these volatile oils may serve as natural alternatives to synthetic antioxidants and preservatives to be applied in food and pharmaceutical industries. Principal component analysis results denoted that some major compounds may be closely related to the antioxidant and antimicrobial activities. It also showed that the volatile oils from Litsea coreana var. lanuginosa and Litsea pungens Hemsl . were characterized by positive values of first two principal components, indicating higher active chemical compounds and antioxidant and antimicrobial activities compared with other species. Thus, they were temporarily considered as good sources of Hawk tea. Graphical
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TALANTA
·
2025
·
IF 6.1
Xueyun Wei,Baorong Zhang,Zhuomin Zhang,Gongke Li
Haloacetic acid (HAA) disinfection by-products (DBPs) with high polarity, low concentration and significant health hazard are widely present during disinfection processes, particularly iodinated and brominated acetic acids. Due to the lack of selective enrichment media, current sample preparation methods are insufficient for efficient enrichment of low concentrations of HAA DBPs in complex samples, which usually influences the analytical sensitivity and accuracy. In this study, a modulator-induced defect formation strategy was employed to prepare defective UiO-66-NH 2 (D-UiO) as a selective enrichment medium which was further fabricated as membrane solid-phase extraction (M-SPE) to efficiently enrich HAA DBPs. The structure and enrichment performance of the D-UiO medium was studied in detail. D-UiO exhibited good extraction selectivity for the five target DBPs in the presence of structural analogs as interfering compounds. Then, a sensitive quantification method by D-UiO based M-SPE was developed for trace brominated and iodinated acetic acid DBPs in tea drinks coupled with ultra-performance liquid chromatography-tandem mass spectrometry. The limits of detection of the method were in the range of 5.0-15.0 ng/L, and the recoveries were in the range of 78.3%-124%. By combining a ten-pass syringe pump with M-SPE technology, this method enabled batch sample processing and significantly reduced pre-treatment time. The method developed was efficient, selective, sensitive, and accurate for the analysis of hazardous HAA DBPs in complex tea drinks.
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FOOD CHEMISTRY
·
2019
·
IF 5.399
Xi Chen,Danhong Wang,Jie Li,Taotao Xu,Keqiang Lai,Qi Ding,Hetong Lin,Lin Sun,Mengshi Lin
There have been increasing concerns among consumers about pesticide residues in Oolong tea. This study aimed to establish surface-enhanced Raman scattering (SERS) method for rapid measurement of chemical contaminants in Oolong tea. Synthesis of SERS substrate was achieved by synthesizing silver nanoparticles (AgNPs) via a reduction method. AgNPs were spherical and highly monodispersed, which created remarkable electromagnetic fields during SERS activities to measure phosmet in the methanol-water solution and Oolong tea. Partial least squares regression models were established to predict the concentrations of phosmet in the methanol-water solution ( r = 0.934; slope = 0.880; RMSEP = 1.001 mg/L) and Oolong tea samples ( r = 0.927; slope = 0.938; RMSEP = 1.157 mg/kg) with the detection limit of 0.1 mg/kg. The results indicate that SERS coupled with silver nanoparticles is a fast, sensitive, and reliable method for detection and characterization of pesticide contaminants in Oolong tea products.
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POLYMER DEGRADATION AND STABILITY
·
2025
·
IF 7.4
Jieyun Zhao,Lina Jiang,Chunlong Zuo,Lei Tan,Wei Tan,Yuanlin Ren,Ping Li,Xiaohui Liu
Triggered by heightened public safety concerns and the imperative of sustainable chemistry, an urgent demand has emerged for the development of eco-friendly and durable flame retardant Lyocell fibers. However, reconciling high flame retardancy, washing durability, mechanical strength, and formaldehyde-free processing within an environmentally benign and feasible approach remains a significant challenge. To address the issue, a novel co-coordination system of biomass tea polyphenols, L-lysine and Fe 3+ , cooperating with covalent linking of 3-epoxypropyl trimethoxysilane was constructed. Compared with Lyocell fabric, the treated Lyocell fabric exhibited substantial reductions of 70.35% for total heat release (THR) and 61.82% for peak heat release rate (PHRR), alongside a limiting oxygen index (LOI) value of 26.8% even after 50 laundering cycles. Meanwhile, the modified fabric had excellent UV resistance, antibacterial and hydrophobic properties. Encouragingly, the proposed modification process basically retained the high mechanical properties of the Lyocell fabrics, providing a sustainable, green route toward multifunctional, durable Lyocell textiles for protective and technical apparel applications.
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Food & Function
·
2025
·
IF 5.4
Qingying Luo,Xuewei Liao,Lijia Zhang,Zhengfeng Fang,Hong Chen,Bin Hu,Yuntao Liu,Zhen Zeng
Lithocarpus litseifolius [Hance] Chun (L. litseifolius), a herbal tea rich in bioactive polysaccharides, has garnered attention for its health-promoting potential. Polysaccharides represent its principal bioactive component and play a significant role in regulating the gut microbiota. This study investigated the physicochemical characteristics and in vitro digestion bioactivities of special-grade polysaccharides (STPs) and first-grade polysaccharides (FTPs) from L. litseifolius green tea, alongside their modulatory effects on the gut microbiota following in vitro fermentation. The results demonstrated that STPs exhibited higher total carbohydrate and uronic acid content, higher molecular weight, and greater in vitro bioactivity compared to FTPs, despite structural similarities. During in vitro simulated digestion, polysaccharides underwent moderate physicochemical modifications accompanied by partial loss of bioactivity. Notably, STPs exhibited a greater extent of degradation compared to FTPs. Despite differential digestion-induced degradation, most STPs and FTPs remained largely intact upon reaching the colon and were thus accessible to the gut microbiota for fermentation. Fecal fermentation demonstrated efficient microbial utilization of STPs and FTPs, each modulating the architecture of the human gut microbiota, characterized by carbohydrate consumption, a decrease in pH, and an elevated relative abundance of beneficial bacterial phyla, including Firmicutes and Bacteroidota. Concurrently, a marked increase in short-chain fatty acid (SCFA) output—particularly acetate and propionate—was observed. STPs primarily enriched Actinobacteria, whereas FTPs favored Bacteroidota, both contributing to elevated acetate and propionate levels while suppressing potential pathogens such as Proteobacteria and Escherichia–Shigella. These findings underscore the potential of L. litseifolius green tea polysaccharides to serve as effective prebiotics for gut microbiota modulation.
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