查找使用阿拉丁产品的科研文献

Extraction of benzoylurea insecticides from tea leaves based on thermoplastic polyethyleneimine embedded magnetic nanoparticle carbon materials

Xiang Li,Xiaofeng Lu,Xiaojing Liang,Yong Guo,Licheng Wang,Shuai Wang

A novel mosaic structured core-shell composite, Silica@C/Ni (Sil@C/Ni), has been prepared by embedding Ni nanoparticles on the surface of silica microspheres via coordination and carbonization reduction, and was used as magnetic solid-phase extraction sorbents in combination with high performance liquid chromatography (HPLC) for the extraction and determination of four benzoylurea insecticides (BUs) in tea leaves. Based on the fact that hydrogen bonding and hydrophobic interactions exist between the material and BUs, allowing BUs on the surface of the material can achieve rapid mass transfer and improved sorption performance, satisfactory extraction recoveries have been achieved in practical sample applications. Under the optimized experimental conditions, the linear ranges were 0.5–200 µg L −1 for diflubenzuron and triflumuron, 1.0–200 µg L −1 for teflubenzuron and 0.8–200 µg L −1 for flufenoxuron with the correlation coefficients R 2  ≥ 0.9991. The method has limits of detection and limits of quantification of 0.2–0.4 µg L −1 and 0.5–1.0 µg L −1 , respectively. The intra-day and inter-day relative standard deviations were less than 5%. The actual sample recoveries were 76.63–95.26%. In addition, Sil@C/Ni was used repeatedly for 15 times and still showed a relatively satisfactory recovery of the four BUs. Therefore, Sil@C/Ni has a high stability and can be used as an ideal magnetic solid phase extraction sorbent for the trace enrichment of BUs in tea-leaf samples.

Cost-effective and sensitive indicator-displacement array (IDA) assay for quality monitoring of black tea fermentation

Huiyan Jia,Wenxuan Yuan,Zhengyu Ren,Jingming Ning,Yong-Quan Xu,Yujie Wang,Wei-Wei Deng

Herein, a new indicator-displacement array (IDA) sensor was developed for the quality evaluation of black tea fermentation. On the principle of the reversible covalent binding of phenylboronic acid and catechol, phenylboronic acids were selected as acceptors for targeted binding to polyphenols. Pyrocatechol violet and alizarin red S were used as indicators of the reaction. The IDA sensors have sensitive differential responses to fermented tea samples, achieving an assessment of the fermentation degree with accuracies of 80.39–88.00% by support vector machine (SVM). In addition, the key polyphenol components of the fermentation process were accurately predicted by the IDA and SVM regression with ratio of prediction to deviation values of 1.55–1.72, 2.03–2.21, and 2.03–2.08 for total polyphenols, total catechins, and epigallocatechin-3-O-gallate, respectively. In conclusion, the developed IDA sensor is capable of the in-situ quality monitoring of black tea fermentation, with the advantages being cost-effectiveness, sensitivity, and rapidity.

Optimization of ultrasonic-assisted extraction model of Pinus koraiensis seed scales oil induced by tea saponin

Zhanjun Li,Yibin Xu,Yunwei Liu,Ke Ma,Kunlun Wang,Fengjian Yang

Tea saponin was used for UAE of oil from Pinus koraiensis seed scales for the first time, and the extraction kinetic model was fitted and compared with that of traditional SE. Considering the relationship among the oil yield, proanthocyanidins content and solvent properties, ethanol was selected as the optimum extraction solvent. PBD and BBD were used to determine the optimal conditions: 63% aqueous ethanol solution, liquid-to-material ratio was 11:1 mL/g, ultrasonic power was 100 W, ultrasonic duration was 15 min, temperature was 45 °C, and the dose of tea saponin was 0.3%. Under the optimal conditions, the oil yield and proanthocyanidins content from P. koraiensis seed scales were 22.73 ± 0.42% and 3.04 mg/g ± 0.08%, respectively. The actual operating value was consistent with the theoretically predicted value. Comparison of the extraction kinetics model, oil components, physical and chemical properties, antioxidants, microstructure of oil residue, energy consumption and ecological emission characteristics of UAE and SE shows that UAE is a more advantageous technique.

Facile Synthesis of MOF-Derived Hierarchical Flower-Like Sr-Doped Co3O4 Structure for Effective TEA Sensing

Heming Sun,Xiaonian Tang

Evaluation of chitosan coatings enriched with turmeric and green tea extracts on postharvest preservation of strawberries

Chun Yang,Jia-Hao Lu,Mei-Ting Xu,Xin-Chi Shi,Zhi-Wei Song,Tang-Min Chen,Daniela D. Herrera-Balandrano,Yun-Jiao Zhang,Pedro Laborda,Mahdi Shahriar,Su-Yan Wang

Strawberries are a widely consumed fruit that contains a variety of antioxidant metabolites. However, postharvest strawberries are highly perishable and susceptible to a variety of fungal pathogens. In this study, a chitosan-based coating containing turmeric (TU) and green tea (GT) extracts was developed and evaluated for the preservation of strawberries. Both TU and GT extracts contained high phenolic contents (>5.8 g kg −1 dry weight), but only TU extract showed strong antifungal activity. SEM observations revealed that high concentrations of extract (3–5% v/v ) caused the formation of agglomerates within the films, reduced elongation at break and increased tensile strength. The postharvest treatment of strawberries with chitosan coating containing TU extract inhibited the proliferation of Botrytis cinerea during 7 d of storage at 20 °C, whereas the coating containing GT extract extended the antioxidant properties of postharvest strawberries from 4 to 8 d at 20 °C. Sensory analysis indicated that the coatings did not significantly affect flavor and taste. Overall, TU extract was used for the first time for food packaging purposes and proved to be a great complement to the antioxidant properties of GT to extend the shelf-life of postharvest strawberries.

Tea Polyphenol Liposomes Overcome Gastric Mucus to Treat Helicobacter Pylori Infection and Enhance the Intestinal Microenvironment

Guiyun Deng,Yang Wu,Zhiyong Song,Shuojun Li,Moqing Du,Jiamin Deng,Quan Xu,Liu Deng,Hagar Shendy Bahlol,Heyou Han

Infection with Helicobacter pylori (Hp) is one of the leading causes of stomach cancer. The ability to treat Hp infection is hampered by a lack of stomach gastric acid environment. This work introduces a nanoliposome that can rapidly adjust the gastric acid environment to ensure a drug’s optimal efficacy. We introduce CaCO3@Fe–TP@EggPC nanoliposomes (CTE NLs) that are composed of Fe3+ and tea polyphenols (TPs) forming complexes on the surface of internal CaCO3 and then with lecithin producing a phospholipid bilayer on the polyphenols’ outer surface. Through the action of iron–TP chelate, the phospholipid layer can fuse with the bacterial membrane to eliminate Hp. Furthermore, CaCO3 can promptly consume the excessive gastric acid, ensuring an ideal operating environment for the chelate. TPs, on the other hand, can improve the inflammation and gut microbes in the body. The experimental results show that CTE NLs can quickly consume protons in the stomach and reduce the bacterial burden by 1.2 orders of magnitude while reducing the inflammatory factors in the body. The biosafety evaluation revealed that nanoliposomes have good biocompatibility and provide a new strategy for treating Hp infection.

Potential prebiotic effects of nonabsorptive components of Keemun and Dianhong black tea: an in vitro study

Wenjing Liao,Wenjiao Li,Suyu Liu,Dong Tang,Yunxi Chen,Yijun Wang,Zhongwen Xie,Jinbao Huang

Black tea is a healthy and popular tea beverage. However, its main bioactive compounds (theaflavins and thearubigins) are not easily absorbed. The aim of this study was to investigate the modulation of intestinal microbiota by the nonabsorptive components of Keemun black tea (KBT) and Dianhong black tea (DBT), and fructooligosaccharide (FOS) was selected for use in the control group. KBT, DBT, and FOS significantly increased total short-chain acid production. Specifically, FOS treatment predominantly increased the production of acetic acids and black tea treatments increased the production of acetic, propionic, and butyric acids at similar rates. Moreover, FOS exerted a strong bifidogenic effect after 24 h of fermentation; KBT and DBT increased the abundance of the beneficial genus Bacteroides and Roseburia . In summary, the nonabsorptive components of KBT and DBT could serve as novel prebiotics, the underlying mechanisms of which are quite different from those of FOS.

Facile synthesis of porous helical activated carbon fibers from waste tea and their electrochemical energy storage

Zhu Shuyuan,Wang Zhijun,Liu Xinglong,Cao Qiyi,Wen Yadong,Cao Ruozhao,Wu Zhiqing,Zhou Cong,Jin Ying,Tao Feng

As a hopeful material for energy storage, helical carbon fibers (HCFs) have attracted wide attention due to their unique morphology and superior properties. However, the facile synthesis of HCFs with high specific surface area (SSA) and good electrochemical performance is still a challenge. In this study, we synthesized HCFs through a catalyst-free strategy using the helical vessels (HVs) extracted from tea as the bio-template and further obtained the helical porous activated carbon fibers (HPACFs) by KOH activation. The as-prepared HPACFs exhibited a high SSA (3124 m 2 ·g −1 ) and developed pore structure, which provided efficient migration of electrolyte ions and electrons, and thus exhibited excellent electrochemical performance for energy storage. For example, HPACF-5 exhibited a specific capacitance of 488 F·g −1 (at 0.5 A·g −1 ) in a three-electrode system and 187 F·g −1 (1 A·g −1 ) in a two-electrode system, with good cyclic stability (loss ~7% after 3000 cycles at 20 A·g −1 ). The helical porous structure with such high SSA provided a combination of defect sites, sufficient active sites, and nanoporous regions in the bends for ion storage. In addition, these structures also improve the ion diffusion and charge transfer during the discharge process, which is in favor of optimized electrolyte ion and energy storage equipment.

Characterization of Key Odorants in Xinyang Maojian Green Tea and Their Changes During the Manufacturing Process

Jilai Cui,Xiaoting Zhai,Danyang Guo,Wenkai Du,Ting Gao,Jie Zhou,Wilfried G. Schwab,Chuankui Song

Xinyang Maojian (XYMJ) green tea is a famous high-grade Chinese green tea, but the key odorants contributing to its aroma have been poorly understood. In this study, solid-phase microextraction and solvent-assisted flavor evaporation were used for sample preparation, and gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactometry (GC–O) were used for both qualitative and quantitative analysis. A total of 50 volatile compounds of five chemical classes were identified in XYMJ tea infusion. Among them, nine odorants including nonanal, β-ionone, octanal, E-nerolidol, linalool, cis-3-hexenyl hexanoate, geraniol, decanal, and β-cyclocitral were identified as key odorants of XYMJ based on GC–O, odor activity values, and aroma combination experiments. Changes in the content of these aroma-active compounds during the manufacturing process of XYMJ (fresh leaves, fixing, rolling, shaping, and drying) were also determined. Most aroma-active compounds decreased after the fixation process, with the exception of cis-3-hexenyl hexanoate. This is the first study to investigate the key odorants in XYMJ using the sensomics approach. The findings of this study provide novel information on the aroma quality of XYMJ.

Proton-coupled electron transfer of catechin in tea wine: the enhanced mechanism of anti-oxidative capacity

Yirong Xia,Xintong Wang,Hechen Sun,Ximing Huang

Tea wine is a Chinese traditional alcoholic drink made by cereal and tea leaves. It is rich in tea polyphenols, caffeine, amino acids, and protons and possesses various healthcare functions. In this work, electrochemical methods, as well as density functional theory (DFT) calculations, were adopted to reveal the proton-coupled electron-transfer process of catechin in tea wine. The electrochemical results showed that the catechin preferred hydrogen-bonding with ethanol and formed molecular clusters. Thus, the direct electron-transfer process of catechin changed to proton-coupled electron transfer. This procedure reduced the energy barrier of the redox reaction and enhanced the anti-oxidative capacity. Subsequently, DFT calculations were employed to explore the bond length, bond energy, and HOMO–LUMO energy gap of catechin, which confirmed the above-mentioned mechanism. Our work offers some positive value for the scientific promotion of traditional food and a greater understanding of the health mechanisms in terms of chemistry.

Tea seed saponins ameliorate cyclophosphamide-induced intestinal injury, immune disorder and gut microbial dysbiosis in mice

Shuna Chen,Jiaxin Kang,Huanqing Zhu,Ziyi Han,Leyu Wang,Kaixi Wang,Junsheng Liu,Yuanyuan Wu,Puming He,Youying Tu,Bo Li

The impacts of tea seed saponins (TSS) on intestinal injury, immune disorder, gut microbial dysbiosis and serum metabolome in cyclophosphamide (CTX)-induced mice were explored. The findings indicated that TSS significantly reversed the spleen index, protected intestinal mucosa , and increased the protein levels of tumor necrosis factor-α (TNF-α), occludin , interleukin-6 (IL-6) and immunoglobulin A (IgA) in colon and small intestine of mice. Microbiome analysis suggested that TSS shaped the gut microbial community structure, and mainly increased the proportion of Bacillus and Alloprevotella . The in vitro experiment further demonstrated the ability of TSS to promote the growth of Bacillus . Serum metabolome analysis showed that TSS significantly upregulated and downregulated 18 and 15 metabolites, respectively. Eight of these compounds were correlated with Bacillus and Alloprevotella . Over all, this work demonstrated that TSS could improve CTX-induced immune imbalance, intestinal barrier disruption and gut microbial dysbiosis, and was a potential candidate for regulating intestinal homeostasis .

PVA@tea tree oil-emulsion core–shell microfiber membranes for extending the shelf life of fruits

Tianliang Dai,Ya Liu,Lina Wang,Juming Yao,Guocheng Zhu,Baochun Guo,Jiri Militk,Dana Kremenakova,Ming Zhang

In this work, a temperature-regulating and antimicrobial–antioxidant fiber membrane was fabricated using coaxial electrospinning technology. The tea tree oil (TTO) emulsion used as the core solution, polyvinyl alcohol (PVA) as the shell solution for coaxial electrospinning, has been demonstrated. Compared with the original PVA fibers, the average diameter of the fibers is increased after coaxial electrospinning, and the diameter increases with the core flow rate. The diameters corresponding to core flow rates of 0.05, 0.1, and 0.15 mL/h are 561, 597, and 849 nm, respectively. Via in vitro release experiment demonstrated that the quantity of TTO released from the composite membrane increased with the elevation of temperature. The inclusions TTO and polyethylene glycol give the film excellent antibacterial–antioxidant properties and a delayed thermal response. More intriguingly, core–shell fiber membranes containing TTO in the core part are effective in slowing down the formation of oxidation spots on the surface of banana compared with pure PVA membranes. Seven days after wrapping bananas with different membranes, the surface of banana in pure PVA film was full of oxidized spots, whereas banana in PVA core–shell fibers showed only one obvious spot.