CRYSTENGCOMM
·
2023
·Vol. 25
·期 40
·5682-5696
·
IF 3.1
Xin-Yue Yuan,Yan Cheng,Jun Liu,Qi-Lei Sun,Fu-Min Xue
A cocrystal screening of a series of theobromine (TBR) with five organic carboxylic acids (p-coumaric acid (p-COA), 2,4,6-trihydroxybenzoic acid monohydrate (2,4,6-TRM), gallic acid monohydrate (GAL), 1-hydroxy-2-naphthoic acid (1-H-2-NA) and citric acid monohydrate (CAM)) with 1 : 1 or 1 : 2 stoichiometry was performed in order to broaden its application in the food and pharmaceutical areas. Six novel multicomponent systems were identified, out of which two nonsolvated single crystals (TBR-2,4,6-TRM, TBR-p-COA) and two hydrated single crystals (TBR-GAL·2H2O, TBR-GAL·4H2O) except for TBR-GAL·2H2O were first reported and the structures of four cocrystal or cocrystal hydrates were determined by SCXRD. The cocrystals of TBR were obtained by the solid-state mechanochemical grinding method and solution-state crystallization. The cocrystal structures were preliminarily determined directly from powder X-ray diffraction (PXRD) data, augmented by information from simultaneous thermal analysis (STA) and Fourier transform infrared spectroscopy (IR). Specifically, the four single crystals were successfully cultured in solution, the structures of which were characterized using the Shelxl method for structure refinement and meticulously searched in the Cambridge Structural Database (CSD). Moreover, the structure determination of the four single crystals was further confirmed by STA and IR assisted by Gaussian calculations. The results led us to the conclusion that TBR and four cocrystal formers (CCF) form a supramolecular system with lower energy. The hydrogen bonding network between TBR and CCF is mainly responsible for cocrystal formation, while TBR-GAL·2H2O and TBR-GAL·4H2O are mainly stabilized by water molecules. The solubilities of TBR, as well as that of cocrystals, were evaluated in two media: pure water and phosphate buffer solution (PBS) (pH 7.2–7.4). Solubilities in water and PBS of cocrystals of TBR-GAL·2H2O and TBR-p-COA were improved by 1.59-fold and 2.98-fold, respectively. Thus, cocrystals significantly influence the solubility of TBR, which could be taken into account in enhancing solubility formulations.
研究领域:
药物化学
·
晶体学
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DOI
高影响因子
JOURNAL OF MOLECULAR SPECTROSCOPY
·
2024
·
IF 1.4
Ningyi Wang,Xinghao Huang,Jiamin Zhang,Xu Wu,Yan Peng,Yiming Zhu
Caffeine, theophylline and theobromine are representative xanthine alkaloids, commonly used as stimulants due to their effects on the central nervous system. Despite their similar molecular structures, they have different pharmacological effects, necessitating a rapid and accurate identification method. In this study, terahertz time-domain spectroscopy (THz-TDS) was used to measure the absorption spectra of these three xanthine alkaloids within the range of 2.0–17.0 THz. The characteristic absorption peaks were visualized and analyzed basing on the quantum chemical calculations using Hartree-Fock (HF), Møller–Plesset perturbation theory (MP2) and density functional theory (DFT). Caffeine exhibited unique absorption peaks at 4.24, 5.00, and 11.13 THz. Theophylline showed characteristic peaks at 9.25, 12.20, and 15.09 THz. While theobromine exhibited characteristic peaks at 4.45, 7.68, and 11.21 THz. The results demonstrate that combining THz-TDS with DFT calculation can non-destructively, efficiently, and accurately identify these xanthine alkaloids, and providing valuable information for further understanding their pharmacological functions.
研究领域:
药物分析
·
光谱学
·
量子化学
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DOI
高影响因子
FOOD CHEMISTRY
·
2024
·
IF 8.5
Lihui Xiang,Chen Zhu,Jiajia Qian,Xiaochen Zhou,Miao Wang,Zhenshuo Song,Changsong Chen,Wenquan Yu,Lin Chen,Lanting Zeng
Most teas, including white tea, are produced from tender shoots containing both leaf and stem. However, the effect of the stem on white tea quality remains unclear, especially during withering, an essential process. Therefore, this study investigated the withering-induced changes in the leaves and stems of Camellia sinensis cv. ‘Fudingdabai’ by multi-group analysis. During withering, the levels of catechin and theobromine (i.e., major flavor-related compounds) decreased slightly, mainly in the leaves. The abundance of some proteinaceous amino acids related to fresh taste increased in stems due to increased protein hydrolysis. In addition, changes in biosynthetic pathways caused a decrease in theanine (a major non-proteinaceous amino acid) and an increase in gamma-aminobutyric acid in stems. Terpenes, mainly in the stems, were partially affected by withering. Phenylacetaldehyde, a major contributor to white tea aroma, increased mainly in the stems. These findings reflect the positive contribution of the stem to white tea quality.
研究领域:
农业科学
·
食品科学
·
植物生理学
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DOI
PubMed
高影响因子
MICROCHIMICA ACTA
·
2013
·Vol. 181
·期 3
·303-311
·
IF 3.434
Zhu Quanfei,Ma Chao,Chen Huaixia,Wu Yaqi,Huang Jianlin
We have prepared a novel caffeine imprinted polymer on a stir bar that can be used for selective extraction of caffeine, theobromine and theophylline from beverages. The polymerization time and quantities of reagents (template, cross-linker, porogenic solvent) were optimized. The morphology of the molecularly imprinted polymer-coating was studied by scanning electron microscopy and Fourier transform IR spectroscopy. A rapid and sensitive method was worked out for the extraction of caffeine, theobromine and theophylline from beverages by using the molecularly imprinted stir bar followed by HPLC analysis. The effects of extraction solvent, stirring speed, desorption solvent, adsorption and desorption time were optimized. The method displays a linear response in the 5–150 μg L −1 caffein concentration range, with a correlation coefficient of >0.9904. The recoveries for three analytes in tea, carbonated and functional beverages were 91–108 %, 90–110 % and 93–109 %, with relative standard deviations ranging from 3.6–5.7 %, 3.5–7.9 % and 3.2–7.9 %, respectively. A molecularly imprinted stir bar was prepared and applied for the selective extraction and sensitive determination of caffeine and its analogues in beverages by coupling with HPLC. The limits of detection were in the range of 1.24–2.25 μg L −1 (S/N = 3) which are lower than those in published papers
研究领域:
分析化学
·
食品科学
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DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 27
·12934-12940
·
IF 3.925
Hansen Yang,Zhimiao Wang,Hualiang An,Qiusheng Yang,Wei Xue,Fang Li,Yanji Wang
Theobromine is an important pharmaceutical intermediate and food additive. We have developed a green method for theobromine synthesis, namely catalyst-free methylation of 3-methylxanthine with dimethyl carbonate (DMC). The effects of various solvents on the reaction were investigated; H2O was found to be the most appropriate solvent. The bond energies of C–O in DMC and N–H in 3-methylxanthine were calculated at the M06-2x/6-311G(d,p) level, and the role of the solvent was examined theoretically. The use of H2O as the solvent and the effects of DMC hydrolysis on the reaction were investigated. The results show that DMC hydrolysis was, to some extent, beneficial to theobromine synthesis. The reaction conditions were optimized. When the molar ratio of DMC to 3-methylxanthine was 11 : 1 and the 3-methylxanthine dosage was 0.1 g per mL-H2O, reaction at 160 °C for 9 h gave a 3-methylxanthine conversion of 89.9% with 98.2% theobromine selectivity.
研究领域:
药物化学
·
绿色化学
·
有机合成
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DOI
高影响因子
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2019
·
IF 2.994
Jin Tan,Rong Li,Zi-Tao Jiang,Shu-Hua Tang,Ying Wang
To circumvent the limitation of conventional high performance liquid chromatography (HPLC) method, synchronous front-face fluorescence spectroscopy was applied for the rapid and non-destructive determination of two major methylxanthines (theobromine and caffeine) and cocoa solid contents in dark chocolate for the first time. Total synchronous fluorescence spectra at wavelength interval (Δλ) between 30–100 nm of 21 brands of commercial dark chocolate bars with labeled cocoa solids of 50–100% were directly obtained at front-face geometry. The contents of the two methylxanthines were determined by HPLC. Partial least squares regression (PLSR) models for quantification were constructed, optimized, and validated by both full ( leave-one-out ) cross-validation and external validation. The coefficients of determination ( R 2 ) values are larger than 0.8, and the relative errors of prediction were ca. 10%. The built models were applied to the detection of four real samples and compared with HPLC method. The combination of front-face fluorescence and PLSR provides a fast and non-invasive procedure for the quantification of theobromine and caffeine in dark chocolate, as an effective alternative for the traditional HPLC method. The further application of the proposed strategy is the rough estimation of cocoa solids in dark chocolate.
研究领域:
食品科学
·
分析化学
·
光谱学
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DOI
高影响因子
FOOD CHEMISTRY
·
2020
·
IF 6.306
Xinlei Yu,Yuchuan Li,Chang He,Jingtao Zhou,Yuqiong Chen,Zhi Yu,Pu Wang,Dejiang Ni
The influence mechanism of different withering methods (CK, indoor natural spreading; LTD, low-temperature plus dark; LTY, low-temperature plus yellow-light; LTCD, low-temperature plus CO 2 ) on non-volatile compounds in postharvest tea leaves was investigated by UHPLC-Q‐TOF/MS-based non-targeted metabolomic and transcriptomic analyses. Compared with CK, low-temperature withering could slow down polyphenol oxidation by inhibiting polyphenol oxidase activity and keeping the expression of genes for flavanol synthesis. After withering, the proteinaceous amino acid content increased significantly, especially for LTCD and LTY, mainly due to increased peptidase activity and up-regulation of genes involved in the biosynthesis of valine, leucine, aspartic acid, glutamic acid, phenylalanine, and proline. Moreover, LTCD and LTY enhanced the synthesis of γ-aminobutyric acid and metabolism of phenylalanine-methyl salicylate and tryptophan-indole, respectively. Meanwhile, the transformation of theobromine to caffeine was accelerated under low-temperature withering. This research provides a genetic metabolic basis for the application of low-temperature withering to actual green tea processing.
研究领域:
农业
·
植物科学
·
代谢组学
·
转录组学
·
食品科学
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DOI
PubMed
高影响因子
JOURNAL OF FOOD SCIENCE
·
2026
·Vol. 91
·期 3
·e70951
·
IF 4.1
Li Xiong,Yangyu Zhou,Ruishu Peng,Yue Xiao,Yina Huang,Hong Gao
This research conducts a systematic exploration of the impacts of three fixation methods—50-type electric heating tube roller fixation (CQ), mixed fixation (HC), and steam fixation (ZQ)—on the quality formation of green tea. By means of quantitative analysis of aroma components, catechins, free amino acids, and alkaloids, in combination with electronic tongue taste fingerprint and untargeted metabolomics analysis, it is discovered that distinct fixation methods exert significant influences on the volatile and non-volatile metabolite profiles of green tea. CQ notably elevated the content of total polyphenols and gallic acid to 3.57 mg/g, intensifying its bitter and astringent taste profile. In contrast, ZQ produced the brightest green infusion and yielded the highest electronic tongue response value for sweetness. HC achieved a superior balance, retaining the highest levels of key aroma compounds like linalool (1.42 mg/kg) and D-limonene, while also preserving the highest total free amino acid content (13,983.2 µg/g). Metabolomics analysis further disclosed that fixation methods affect metabolite composition by regulating pathways such as phenylpropanoid biosynthesis and caffeine metabolism. Molecular docking experiments verify that the disparity in binding affinity between key differential metabolites (e.g., Chrysophanol 8-(6-galloylglucoside)) and taste receptors (TRPM5, TAS2R14, T1R1/T1R3) serves as the material foundation for taste differentiation. This study provides a theoretical basis for the development of precision processing technologies and quality control of green tea. Practical Applications This study provides a decision-making framework for green tea producers to select fixation techniques based on desired sensory profiles. To enhance floral and citrus notes, mixed fixation (HC) is recommended. Steam fixation (ZQ) is ideal for preserving a bright green color and sweeter taste, suitable for premium-grade teas. Roller fixation (CQ) can be applied where a stronger, more astringent profile is targeted. These insights enable the precision manufacturing of green teas with customized flavor characteristics.
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PubMed
高影响因子
ANALYTICA CHIMICA ACTA
·
2026
·
IF 6.1
Yali Yang,Hui Ding,Kaijun Quan,Hongwei Zhao,Mingxia Sun,Zhimin Yang,Xiuhui Liu,Hongdeng Qiu,Jia Chen
Background To address the limitations of traditional single-mode stationary phases in separating complex samples, mixed-mode or multi-mode chromatographic stationary phases, which can provide two or more interaction mechanisms, have attracted extensive research interest. Among them, sulfonated pyrene derivatives present a promising candidate ligand, as they synergistically retain the hydrophobicity and π-π interaction capability of the pyrene moiety along with the hydrophilicity and strong cation-exchange capacity provided by the sulfonic acid groups. This synergistic multi-mechanism design significantly enhances separation selectivity for diverse and complex components. Results A pyrene trisulfonic acid-functionalized silica stationary phase (Sil-PyTSa) was successfully prepared and evaluated. In hydrophilic interaction liquid chromatography (HILIC) mode, Sil-PyTSa could efficiently separate nucleobases and nucleosides, ginsenosides, and alkaloids. For nucleobases and nucleosides, it utilized hydrophilic, electrostatic, and π-π interactions, showing superior retention and selectivity over a control HILIC column. In reversed-phase liquid chromatography (RPLC) mode, favorable separation of PAHs was achieved via hydrophobic and π-π interactions, enabling faster analysis and lower solvent consumption than a C18 column. In ion-exchange chromatography (IEC) mode, baseline separation of 14 rare earth elements (REEs) and removal of Fe/U impurities were accomplished. The column efficiency reached 95,920 N/m for naphthalene. Additionally, Sil-PyTSa achieved effective separation for REEs and iron (Fe) in a simulated NdFeB leaching solution and detected nucleobases and nucleosides in Angelica, indicting promising potential for analyzing complex matrices. Significance and novelty This work developed a novel multi-mode chromatographic stationary phase with multiple interactions mechanisms to enable high-performance separations in HILIC, RPLC, and IEC modes. It demonstrates good separation efficiency and selectivity, low solvent consumption, and high stability. This offers a versatile and green solution for the separation of complex samples with diverse analytes.
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PubMed
高影响因子
Foods
·
2026
·Vol. 15
·期 2
·212
·
IF 5.1
Dunchao Wu,Yufei He,Juanshu Wen,Hongfa Zheng,Xi Zhao,Penghui Yu,Ni Zhong,Li Niu,Shi Li,Yong Lin,Hao Huang,Zhonghua Liu
Pile fermentation is a crucial process for developing the characteristic mellow taste and aged aroma of dark tea, yet the internal quality transformation mechanism of this process is still unclear. This study employed a high-sensitivity analytical platform based on gas chromatography–mass spectrometry (GC-MS) to systematically investigate the dynamic interplay between key chemical components, enzyme activities, and volatile compounds during the pile fermentation of primary dark tea. Our findings revealed a significant decrease in ester-type catechins, crude protein, and protopectin, alongside a notable accumulation of non-ester-type catechins, gallic acid, and soluble components. The multi-enzyme system—comprising PPO/POD, pectinase/cellulase, and protease—cooperatively drove the oxidation of phenols, cell wall degradation, and the release of aromatic precursors. This was complemented by GC-MS analysis, which identified and quantified 103 volatile compounds across nine chemical classes. The total content of volatile compounds increased significantly, with alcohols, esters, and aldehydes/ketones being the dominant groups. Floral and fruity compounds such as linalool and geraniol accumulated continuously, while esters exhibited an initial increase followed by a decrease. Notably, carotenoid degradation products, including β-ionone, were significantly enriched during the later stages. This study revealed a “oxidation–hydrolysis–reconstruction” metabolic mechanism co-driven by microbial activity and a multi-enzyme system, providing a theoretical foundation for the precise regulation of pile fermentation and targeted quality improvement of primary dark tea.
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DOI
PubMed
高影响因子
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2026
·
IF 4.6
Zheng-Yun He,Jun Xiang,Xing-Zi Ding,Qing-Qing Luo,Hui-Wen Gu,Xiao-Li Yin
This study investigated the distribution of signature components in renowned Chinese green teas to develop a method for authenticity identification. By employing high-performance liquid chromatography-diode array detection (HPLC-DAD) coupled with the alternating trilinear decomposition (ATLD) algorithm, a second-order calibration model was constructed that effectively addressed the challenge of co-elution peaks in complex tea matrices. The method demonstrated satisfactory accuracy, with spiked recoveries ranging from 93.5% to 119.6% and relative standard deviations (RSDs) below 1.10% for all analytes. Using the established ATLD-enhanced HPLC method, a quantitative analysis of ten major components in 37 Chinese green teas was conducted, and their distribution patterns were visualized. Based on these quantitative results, multivariate statistical analysis methods, principal component analysis (PCA) and orthogonal projections to latent structures discriminant analysis (OPLS-DA) were subsequently employed to effectively utilize the data for authenticity discrimination concerning the geographical origin, variety, and grade of the teas. The results revealed that characteristic components varied significantly with tea origin, variety, and grade, enabling the authenticity identification of green tea. These findings not only confirm the efficacy of key catechins for authenticity identification but also establish an analytical strategy for quality evaluation, providing a powerful framework for industrial quality control and origin verification.
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高影响因子
Foods
·
2026
·Vol. 15
·期 16
·2876
·
IF 6
Anran Yan,Weiyi Kong,Xinyu Feng,Ning Tang,Fangyuan Fan,Ping Chen,Binggan Lou,Qiang Chu,Ruili Zhang
Flavored teas have gained popularity because they combine sensory appeal with potential health benefits.Ganoderma lucidum(GL) is a promising functional beverage ingredient owing to its high medicinal value. However, its strong fungal off-flavor and bland taste limit consumer acceptance. Yellow tea (YT), characterized by a mild-sweet aroma and mellow mouthfeel developed during sealed yellowing, provides a suitable matrix for moderating the sensory defects of GL. This study designed a blend-brewing strategy, optimizing the YT to GL ratio (2:3,w/w) and comparing covered (CB), standard (SB), and open-topped brewing (OB) methods. SB achieved the most balanced sensory profile. In contrast, CB intensified bitterness and astringency, which were associated with higher concentrations of EGCG, gallic acid, and theobromine, whereas OB produced a relatively flat taste because of insufficient extraction. Brewing also reshaped self-assembled nanoparticles, with CB inducing pronounced aggregation and SB yielding a broader size distribution, smoother surfaces, and more balanced colloidal proteins, catechins, and caffeine. Removing nanoparticles substantially decreased infusion mellowness, supporting a contribution of the NP-enriched fraction to mouthfeel. These findings demonstrate thatGanoderma lucidumyellow tea (GY) blending and brewing method modulate sensory quality through chemical extraction and colloidal nanoparticle organization, providing a practical strategy to improveGanoderma lucidumpalatability and develop functional tea beverages.
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高影响因子
危险品化学品经营许可证（带存储）