Nanomaterials
·
2025
·Vol. 15
·期 5
·385
·
IF 4.3
Yuanyuan Yuan,Baohui Li,Keqing Zhang,Hongtao Zhu
A covalent organic framework TPB-DMTP was physically coated onto the gully-like surface of stainless-steel fiber. The fabricated TPB-DMTP-coated stainless-steel fiber was used to extract five phthalic acid esters (PAEs) prior to the GC-FID separation and determination in bottled tea beverages. The developed SPME-GC-FID method gave limits of detection (S/N = 3) from 0.04 µg·L−1(DBP) to 0.44 µg·L−1(BBP), with the enrichment factors from 268 (DEHP) to 2657 (DPP). The relative standard deviations (RSDs) of the built method for inter-day and fiber-to-fiber were 4.1–11.8% and 2.3–9.9%, respectively. The prepared TPB-DMTP-coated stainless-steel fibers could stand at least 180 cycles without a significant loss of extraction efficiency. The developed method was successfully applied for the determination of trace PAEs in different bottled tea beverages, with recoveries from 85.5% to 115%.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2019
·
IF 3.571
Xueli Pang,Weisong Yu,Changdai Cao,Xiaoxiang Yuan,Jun Qiu,Fanyu Kong,Jihong Wu
Infusions prepared from raw pu-erh tea (RAPT) and ripened pu-erh tea (RIPT) showed remarkable aroma differences. Predominant odorants in RAPT and RIPT infusions were identified and compared by the combined use of gas chromatography–olfactometry, aroma extract dilution analysis, odor activity values (OAVs), and multivariate analysis. A total of 35 and 19 odorants (OAV > 1) were detected in RIPT and RAPT, respectively. Odorants in RAPT and RIPT are significantly different in both odor properties and aroma compound intensities. Overall, RAPT contained a complex variety of chemical classes with diverse odors and moderate odor intensities, while RIPT is dominated by structurally and organoleptically similar compounds with high potency. Specifically, stale and musty smelling methoxybenzenes contributed the most to RIPT, while floral-, sweet-, and woody-smelling terpene alcohols, terpene ketones, and phenolic compounds were the predominant odorants in RAPT. Orthogonal partial least squares discriminant analysis revealed that linalool, α-ionone, 1,2,4-trimethoxybenzene, 1,2,3-trimethoxy-5-methylbenzene, 1,2,3,4-tetramethoxybenzene, and 1,2,3-trimethoxybenzene underwent remarkable changes during pile fermentation and could be used as potential odor-active markers for RIPT and RAPT discrimination. The comprehensive aroma characterization of pu-erh tea and determination of the effect of pile fermentation on odorant alteration herein will provide guidance for pu-erh tea flavor quality control and evaluation.
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FOOD CHEMISTRY
·
2025
·
IF 9.8
Jinjie Hua,Xiwang Li,Chun Zou,Liyue Yang,Wen Ouyang,Ming Chen,Xinxin Lv,Fenglan Zhang,Xizhe Zhu,Ting An,Jinjin Wang,Jiayi Zhu,Haibo Yuan,Yongwen Jiang
Fixation is key for green tea flavor formation; however, the impact of fixation methods on non-volatile metabolites (NVMs) and volatile metabolites (VMs) regulation remains unclear. We applied objective quantification techniques, widely targeted metabolomics, and aroma-omics to analyze the influence of fixation methods on green tea quality. Roller-hot air coupling fixation (RHF) produced an umami taste with a chestnut aroma, whereas roller-steam coupling fixation (RSF) produced a tender aroma with bitterness. We detected 498 NVMs and 63 VMs, and 14 key quality-differential NVMs and 7 key VMs were identified. KEGG revealed flavonoid, amino acid, glycoside, and carotenoid metabolism were the key pathways caused by fixation methods resulting in green tea flavor difference. RHF accelerated flavonoid transformation and amino acid formation metabolism, resulting in higher L-glutamic acid and catechin contents, lower rutin and l -lysine contents. These results provide a theoretical and technical support for precise targeted processing of high-quality green tea.
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NEW PHYTOLOGIST
·
2024
·
IF 8.3
Honglian Gu,Jiaxing Li,Dahe Qiao,Mei Li,Yingjie Yao,Hui Xie,Ke-lin Huang,Shengrui Liu,De-Yu Xie,Chaoling Wei,Junyan Zhu
Summary Numerous herbivore-induced plant volatiles (HIPVs) play important roles in plant defense. In tea plants ( Camellia sinensis ), (Z)-3-hexenyl acetate (3-HAC) has been characterized as associated with resistance to herbivores. To date, how tea plants biosynthesize and regulate 3-HAC to resist herbivores remain unclear. Based on transcriptomes assembled from Ectropis obliqua- fed leaves, a cDNA encoding BAHD acyltransferase, namely CsCHAT1 , was highly induced in leaves fed with E. obliqua . Enzymatic assays showed that CsCHAT1 converted (Z)-3-hexenol into 3-HAC. Further suppression of CsCHAT1 expression reduced the accumulation of 3-HAC and lowered the resistance of tea plants to E. obliqua , while 3-HAC replenishment rescued the reduced resistance of CsCHAT1 -silenced tea plants against E. obliqua . Two transcription factors (TFs), CsNAC30 and CsTCP11 , were co-expressed with CsCHAT1 . An integrative approach of biochemistry, DNA–protein interaction, gene silencing, and metabolic profiling revealed that the two TFs positively regulated the expression of CsCHAT1 . The suppression of either one decreased the production of 3-HAC and eliminated the resistance of tea plants to E. obliqua . Notably, the suppression of either one considerably impaired JA-induced 3-HAC biosynthesis in tea plant. The proposed pathway can be targeted for innovative agro-biotechnologies protecting tea plants from damage by E. obliqua .
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TALANTA
·
2025
·
IF 6.1
Yuanyuan Zheng,Manyi Wang,Mengyuan Lv,Yu Huang,Bingyu Wang,Chenqi Niu,Di Chen
This study presents a novel liquid-filled stick microextraction (LFSME) method for the efficient extraction of hydrophobic compounds from aqueous samples. The LFSME device, inspired by a single-use swab, consists of a hollow plastic stick pre-filled with a hydrophobic deep eutectic solvent (DES), and wrapped with polypropylene fabric at the end. Upon activation, the DES is released and absorbed by the polypropylene fabric, enabling direct immersion into the sample solution for efficient extraction. The extracted analytes are subsequently desorbed with acetonitrile and analyzed by liquid chromatography-ultraviolet detection. The method demonstrated excellent analytical performance, including high enrichment factors (34–90), good linearity (R 2 > 0.99), and low limits of detection (LODs: 0.99–2.61 ng/mL) for the five target triazole pesticides. The disposable and portable nature of the LFSME device eliminates the need for complex sample handling, providing a cost-effective and user-friendly solution for routine monitoring of pesticide residues and other contaminants in complex matrices.
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JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2020
·
IF 3.721
Hui Wang,Lili Hu,Peng Zhou,Li Ouyang,Bo Chen,Ying Li,Yaya Chen,Yan Zhang,Jinsha Zhou
A solid phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC–MS/MS) method was developed for simultaneous determination of fructose, glucose and sucrose in tea. Tea samples were ultrasonically extracted with ultrapure water and cleaned up by Oasis PRIME HLB SPE cartridge. The separation of the analytes was performed on XBridge BEH Amide column (2.1 × 150 mm, 5 μm) with isocratic elution. Detection of the target compounds were carried out under the multiple reaction monitoring (MRM) mode with negative electrospray ionization (ESI − ). The qualitative screening was achieved with retention time and qualitative ion, then confirmation analysis with peak area and quantitative ion. The limits of detection (LODs, S/N ≥ 3) of fructose, glucose and sucrose were 0.02 mg/L, 0.03 mg/L and 0.08 mg/L, respectively. The average recoveries varied from 92.1 %–108.5 % for three levels. Linearity was obtained with the correlation coefficients greater than 0.992 for three target compounds. The established method was rapid, simple and accurate which was suitable for batch determination of fructose, glucose and sucrose in tea. A total of 213 tea samples from 7 countries were analysed and the results statistically analyzed using MATLAB software. Moreover, source and adulteration analysis of sucrose in tea was carried out. Sucrose in tea is mainly derived from photosynthesis during growth, hydrolysis of polysaccharides during the processing and artificial adulteration, once the sucrose content in tea exceeds 24.3 g/kg, it may involve artificial adulteration.
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JOURNAL OF SOLID STATE CHEMISTRY
·
2020
·
IF 2.726
Tao Chen,Jie Ding,Tianyu Liu,Qi Li,Yanping Luo,Longzhang Dong,Hongbin Du,Min Fang,Jianchun Bao,Yong Wu
A 3D, anionic novel porphyrinic metal-organic framework (PMOF) 1 having [NH 2 (CH 3 ) 2 ] + as counterions and Li + -exchanged version of 1 ( Li + -1 ) were synthesized. A very interesting feature of 1 and Li + -1 is their frameworks can change shape without breaking bonds, causing substantial changes of their PXRD patterns depending on what and how much is in the channels. Li + -1 has much larger surface area (Langmuir: 640 m 2 /g), compared with the 339 m 2 /g of PMOF 1 . The CO 2 adsorption capacities of 1 and Li + -1 are 38 (7.5 wt%) and 45 mL/g (8.9 wt%), respectively at 1 atm and 298 K, and 165–167 mL/g (33%) at 9.9 atm. They are direct-bandgap semiconductors with bandgaps of 1.56 (for 1 ) and 1.62 (for Li + -1 ) eV. The conduction and valence band-edge positions were determined in non-aqueous solutions as −0.29 and 1.27 ( 1 ), −0.32 and 1.30 V ( Li + -1 ) versus NHE. PMOF 1 or Li + -1 /Ru(bpy) 3 Cl 2 /TEA/CH 3 CN (bpy = 2,2-bipyridine, TEA = triethylamine) system photocatalytically reduce CO 2 to CO under visible light. PMOFs act as cocatalysts, and the photocatalysts were found to be the triplet excited state of Ru(bpy) 3 2+ ( Ru(II)∗ ) and its photodecomposition products. The TOFs contributed from PMOFs after 2 h were 0.091 and 0.097 h −1 (224 and 241 μmol g −1 h −1 ), respectively for 1 and Li + -1 , respectively. In addition, the Ru(bpy) 3 Cl 2 /TEA/CH 3 CN system were found to have an unprecedented high TOF of 0.31 h −1 (412 μmol g −1 h −1 ) when small amounts of H 2 O (200 μL H 2 O in 40 mL CH 3 CN and 10 mL TEA) was added.
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Food Chemistry-X
·
2023
·
IF 6.1
Jun Li,Fangbo Yuan,Jiayou Teng,Fang Li,Penghui Zhou,Yanlan Bi
The effects of tea polyphenols (TP) on the quality of palm oils (PO) and losses of endogenous vitamin E during batch frying of instant noodles as well as oxidative stability of fried instant noodles were investigated. PO without antioxidant addition was negative control and with tertiary butylhydroquinone (TBHQ) addition positive control. TP and TBHQ addition inhibited the increase of peroxide, p -anisidine, and total oxidation values of PO and reduced tocopherol and tocotrienol losses with 200 mg/kg of TP having the best performance, but didn’t affect acid value and triglyceride composition. 200 mg/kg of TP and 100 mg/kg of TBHQ inhibited unsaturated fatty acid losses. During frying, TBHQ was mainly volatilized but TP transformed. TP more effectively reduced tocopherol and tocotrienol losses than TBHQ, reducing PO deterioration. The extended lifecycles of PO and shelf life of fried instant noodles are attributed to nonvolatility of TP and antioxidative properties of its transformation products.
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MICROCHEMICAL JOURNAL
·
2019
·
IF 3.206
Zhihong Shi,Jing Jiang,Weiyue Pang,Hongyu Ma,Xiaoxue Chu,Can Zhou,Hongyi Zhang
In this study, carbon fibers (CFs) were used as sorbent material for the dispersive micro-solid phase extraction (d-μSPE) of anthracene , acenaphthene and phenanthrene from tea infusion samples prior to gas chromatography-quadrupole mass spectrometric detection. CFs were obtained by carbonizing cotton at 800 °C under the protection of nitrogen for 4 h. After characterization by the scanning electron microscopy-energy dispersive spectrometry, X-ray diffraction and N 2 adsorption-desorption, 20 mg of CFs were used to effectively adsorb PAHs in 5 min from 10 mL of tea infusion samples, 2 mL of toluene was used as desorbent . Under the optimum conditions, good linearity was obtained with R 2 between 0.9996 and 0.9998. The limits of detection were in the range of 0.012–0.014 μg/L. RSD values for intra- and inter-day precision were ≤6.7% and ≤7.8%, respectively. In this work, cotton based CFs were prepared in a solventless and green way and the CFs based d-μSPE procedure was simple, rapid and cost-effective, with no need of column-packing. The proposed method has been successfully applied to the analysis of PAHs in three kinds of tea infusion samples.
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JOURNAL OF SEPARATION SCIENCE
·
2019
·Vol. 42
·期 7
·1304-1311
·
IF 2.516
Guanwei Gao,Hongping Chen,Yunfeng Chai,Lili Jin,Xin Liu,Chengyin Lu
Phthalimide can be formed from either the degradation of folpet and phosmet, or reaction of phthalic anhydride with primary amino groups. Consequently, the sum of phthalimide and folpet, expressed as folpet-residue definition, is highly prone to false-positive levels of folpet in tea. An analytical method is thus urgently needed to investigate the residue level and source of phthalimide in tea. In this work, we developed an accurate method of determining phthalimide and phthalic acid (the indicator of phthalic anhydride) by acetonitrile extraction and 3-bromopropyltrimethylammonium bromide derivatization coupled with ultra high performance liquid chromatography and high-resolution mass spectrometry. The method was validated, and linearity (correlation coefficients > 0.99) was obtained. Satisfactory recoveries at 10, 20, 50, and 100 μg/kg ranged from 76 to 117%, and the intra- and interday accuracies were <23%. The limit of quantification for phthalimide and phthalic acid was 10 μg/kg. The developed method was further successfully used to determine phthalimide and phthalic acid in some tea samples. The positive rate of phthalimide and phthalic acid detected in the tea samples ranged from 30–75 and 50–90%, respectively.
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JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
·
2012
·
IF 2.888
Mantong Song,Tiejie Wang,Qing Li,Longshan Zhao,Huijuan Fang,Dongxiang Li,Kaishun Bi
A liquid chromatography hybrid ion trap time-of-flight mass spectrometric (LC–IT-TOF-MS) method was developed and validated for identification and simultaneous determination of the potential bioactive components from green tea in rat plasma. The plasma samples were extracted by liquid–liquid extraction with ethyl acetate and separated on Shim-pack XR-ODS II column by a gradient elution within a runtime of 8.0 min. The mobile phase consisted of A (0.1% formic acid in acetonitrile) and B (0.1% formic acid in water) at a flow rate of 0.4 ml/min. Two prototype components and one metabolite were successfully identified as caffeine, theobromine and theophylline according to their retention times, accurate molecule weight, and major fragment ions. Then they were determined with the addition of two internal standards, hypoxanthine and paracetamol. The linear range was 10–10,000 ng/ml for caffeine, 2.0–2000 ng/ml for theobromine and 1.0–1000 ng/ml for theophylline, respectively. Intra-day and inter-day precision were within 6.0% and 10.9%, and accuracy was less than 4.8% and 6.5%, respectively. The validated method was successfully applied to investigate the dynamic change rules of caffeine, theobromine and theophylline in rat plasma after oral administration of caffeine, theobromine and green tea extract. The comparative analysis of the pharmacokinetic parameters indicated that there were obvious differences between green tea extract administration and single substances administration.
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FOOD RESEARCH INTERNATIONAL
·
2017
·
IF 3.086
Chao Wang,Chenxia Zhang,Yawen Kong,Xiaopei Peng,Changwen Li,Shunhang Liu,Liping Du,Dongguang Xiao,Yongquan Xu
Dianhong teas produced from fresh leaves of different tea cultivars (YK is Yunkang No. 10, XY is Xueya 100, CY is Changyebaihao, SS is Shishengmiao), were compared in terms of volatile compounds and descriptive sensory analysis. A total of 73 volatile compounds in 16 tea samples were tentatively identified. YK, XY, CY, and SS contained 55, 53, 49, and 51 volatile compounds, respectively. Partial least squares–discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA) were used to classify the samples, and 40 key components were selected based on variable importance in the projection. Moreover, 11 flavor attributes, namely, floral, fruity, grass/green, woody, sweet, roasty, caramel, mellow and thick, bitter, astringent, and sweet aftertaste were identified through descriptive sensory analysis (DSA). In generally, innate differences among the tea varieties significantly affected the intensities of most of the key sensory attributes of Dianhong teas possibly because of the different amounts of aroma-active and taste components in Dianhong teas.
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危险品化学品经营许可证（带存储）