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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PubMed
高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
·
2026
·
IF 7.1
Yi He,Shulin He,Xuemei Fan,Lin Gan,Ishak Ahmad,Wan Hafizi Wan Ishak,Chaojiu Long,Kun Qian,Jin Huang,Yongqiang Zhang
Engineered a TP/GB-assisted polysaccharide quaternary preservation coating. • Extended mango shelf life over 11 days via physiology and antibacterial action. • Identified C. siamense via morphology and Koch's postulates. • Revealed TP-enhanced binding of polysaccharide-CSH by molecular docking. • Confirmed ecological safety after washing using soil and aquatic bioassays. Climacteric mangoes suffer a short shelf life due to rapid postharvest nutrient loss and pathogen invasion. Herein, a strategy of quaternized chitosan (QCS)/cellulose nanocrystal (CNC) coating incorporating complementary glycine betaine (GB) and tea polyphenols (TP) functionalities was developed through integrated metabolic regulation and antifungal-antioxidant functionalities. The prepared QCS/CNC/TP/GB-10 coating exhibited water vapor permeability (WVP) of 0.41 × 10 −3 g m −1 ·kPa −1 ·h −1 and oxygen permeability (OP) of 0.10 cm 3 μm·m −2 ·d −1 ·kPa −1 , respectively, with improvements of 38.1% and 61.5% over QCS. The 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging rate reached 91.93 ± 1.49%, 75.29% higher than QCS. Mangoes treated with QCS/CNC/TP/GB-10 extended shelf life by 11 days, with weight loss of 23.22 ± 0.83% and firmness loss of 32.69 ± 2.20%, respectively. The titratable acidity (TA) was maintained at 0.20%, significantly higher than controls (<0.07%). Colletotrichum siamense ( C. siamense ) was identified as the causal agent, and the QCS/CNC/TP/GB-10 coating achieved 67.02 ± 2.35% inhibition, 2.23-fold higher than QCS. Molecular docking suggested TP-assisted binding enhancement between QCS/CNC and the CSH protein of C. siamense , with GB showing limited contribution. Soil and aquatic organism models demonstrated no ecological risks of the coating solution. This study provides a design paradigm for developing promising polysaccharide-based coatings for climacteric fruit preservation.
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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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PubMed
高影响因子
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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Insects
·
2022
·Vol. 13
·期 11
·1056
·
IF 3.139
Nanxia Fu,Fida Hussain Magsi,Yingjie Zhao,Xiaoming Cai,Zhaoqun Li,Lei Bian,Chunli Xiu,Zongmao Chen,Zongxiu Luo
Simple SummaryThe tea tortrixArchips strojnyis a major pest of spring tea in China. Using sex pheromone-based mass trapping or mating disruption techniques to control this pest can minimize excessive pesticide usage, thereby maintaining pesticide residues within the safety standard for spring tea products. However, the sex pheromone components of this species remain elusive. In this study, we identified these components: laboratory assays showed that two bioactive compounds in female sex pheromone gland extracts, namely, (Z)-11-tetradecenyl acetate (Z11-14:Ac) and (Z)-11-tetradecenyl alcohol (Z11-14:OH), could elicit male moth antennal responses. A field trapping assay demonstrated that Z11-14:Ac was the attractant in the sex pheromone, while Z11-14:OH seemed to be an antagonist. Overall, our results indicated that lures baited with 1 mg of Z11-14:Ac could be used as a monitoring or mass trapping tool forA. strojnymanagement in Chinese tea plantations. Furthermore, Z11-14:Ac was found to be a common attractant in the sex pheromones of nine leafroller species in the genusArchips. Thus, Z11-14:Ac may be used to develop a mating disruption technique targeting multiple leafroller species.AbstractPesticide application is the only known control method for the tea tortrixArchips strojny(Lepidoptera: Tortricidae), which is a major pest of spring tea in China. To develop sex pheromone-based, environmentally safe control strategies, here we identified the sex pheromone components of this species. The male moths’ antennae responded electrophysiologically to two compounds in female pheromone gland extracts. Gas chromatography–mass spectrometry analysis indicated that the two bioactive compounds were (Z)-11-tetradecenyl acetate (Z11-14:Ac) and (Z)-11-tetradecenyl alcohol (Z11-14:OH). Field trapping assays showed that lures baited with only the major component Z11-14:Ac were the most attractive to male moths, and the attractiveness decreased significantly when the lure was impregnated with increased relative ratios of the minor component Z11-14:OH. Our study demonstrated that Z11-14:Ac was the major attractant in theA. strojnysex pheromone, and the minor component Z11-14:OH seemed to serve as an antagonist. The results indicate that lures baited with 1 mg of Z11-14:Ac could be used as a monitoring or mass trapping tool forA. strojnymanagement in Chinese tea plantations. Furthermore, Z11-14:Ac was identified as a common sex pheromone attractant of nineArchipsspecies; these results lay the foundation for developing mating disruption techniques that target multiple leafroller pests.Keywords:female sex pheromone;Archips strojny;(Z)-11-tetradecenyl acetate;male attraction;tea pest
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RUBBER CHEMISTRY AND TECHNOLOGY
·
2022
·Vol. 95
·期 3
·450-464
·
IF 2.081
Wang Xiaolei,Pan Hongwei,Cao Lan,Wang Chunfu,Zong Chengzhong
Tea polyphenols and vitamin C are used as reducing agents that are introduced into nitrile–butadiene rubber (NBR) and NBR/graphene oxide (GO) latex systems, and the double bonds in the NBR and the GO sheet in NBR/GO are simultaneously hydrogenated and reduced through the synergistic hydrazine hydrate/hydrogen peroxide/copper sulfate catalytic system to prepare hydrogenated NBR (HNBR) and HNBR/reduced GO (RGO) nanocomposites. The degree of hydrogenation of the product is improved and the gel content of the product is reduced, which effectively solves the problems of the low degree of hydrogenation and high gel content in the diimide catalytic hydrogenation system. At the same time, the HNBR and HNBR/RGO nanocomposites, which are co-reduced by tea polyphenols and vitamin C, have good thermal stability and mechanical properties. Tea polyphenols are more likely to participate in the hydrogenation reaction. The degree of hydrogenation of the NBR double bonds is higher than the amount of reduction occurring within the GO sheet with the addition of tea polyphenols.
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高影响因子
PLANT AND SOIL
·
2025
·
IF 4.1
Shi Huai,Liu Guohong,Chen Qianqian,Zheng Xiangzhou
Aims Tea plants exhibit a strong preference for ammonium nitrogen (NH₄⁺-N), yet organic fertilizers release nitrogen slowly and are prone to nitrate leaching, createting a dual challenge of insufficient supply and loss. This study aimed to validate a synergistic strategy combining ammonifing bacteria and nitrification inhibitors to enhance organic nitrogen mineralization and NH₄⁺-N retention in tea plantion soils, and to elucidate the underlying microbial mechanisms. Methods A 56-day soil incubation experiment tested five treatments: control (CK), organic fertilizer (OF), OF with ammonifying bacteria (OM), OM + dicyandiamide (OMN1), and OM + 3,4-dimethylpyrazole phosphate (OMN2). Soil NH 4 + -N /NO 3 − -N dynamics, microbial communities, and functional genes were analyzed. Field trials further assessed the agronomic effects of four treatments (CK, OF, OMN1, OMN2) on tea yield and quality. Results The combined use of ammoniating bacteria and nitrification inhibitors synergistically enhanced NH 4 + -N availability by accelerating organic N mineralization and suppressing nitrification. This strategy reshaped microbial co-occurrence networks and enhanced the expression of nitrogen metabolism genes without altering overall diversity. enabling targeted N supply regulation. Field validation confirmed significant improvements in tea yield and quality. Conclusions Synergistic regulation of microbial nitrogen transformation offers a promising approach to optimize organic fertilization in tea plantations. By enhancing NH₄⁺-N supply and reducing nitrification loss, this strategy improves both soil nitrogen dynamics and tea production outcomes.
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产品关联
DOI
高影响因子
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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高影响因子
ChemistrySelect
·
2025
·Vol. 10
·期 43
·e04072
·
IF 2
Xiao Bai,Yinxue Zhou,Chunyan Lv,Fanjun Zhang,Ziyin Yang,Zhe Liu
This work demonstrates that Zn single atoms exhibit intrinsic oxidase-like activity. Zn single-atom nanozymes (Zn-SAs/NC) were synthesized via direct pyrolysis of ZIF-8 at 1000 °C under N 2 atmosphere, which retains a rhombic dodecahedral morphology with atomically dispersed Zn sites. Crucially, Zn-SAs/NC exhibited pronounced oxidase-like activity, efficiently catalyzing the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxTMB without exogenous H 2 O 2 . Control experiments with metal-free NC confirmed that the catalytic activity originated specifically from the Zn single atoms, challenging the traditional view of Zn's catalytic inertness. The Zn-SAs/NC-catalyzed TMB oxidation system was exploited for colorimetric detection of tannic acid (TA) based on TA's inhibitory effect, achieving high sensitivity (LOD = 0.016 µM) and selectivity. Successful application in real tea samples validated the method's practicality, establishing Zn single atoms as a novel nanozyme platform. Graphical This work develops a Zn single-atom nanozyme (Zn-SAs/NC) derived from ZIF-8 pyrolysis, which exhibits robust intrinsic oxidase-like activity for highly sensitive and selective colorimetric detection of tannic acid with a low detection limit of 0.016 µM.
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高影响因子
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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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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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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危险品化学品经营许可证（带存储）