FOOD CHEMISTRY
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2015
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IF 3.391
Fang-Yuan Fan,Meng Shi,Ying Nie,Yue Zhao,Jian-Hui Ye,Yue-Rong Liang
Tea catechins as a member of flavan-3-ols subclass with the same skeleton may behave differentially. This study investigated the chemical conversions of 8 catechins under heat treatment with the involvement of epimerization, hydrolysis and oxidation/condensation reactions. Three reactions were enhanced as temperature increased from 30 °C to 90 °C. The epimerization of non-gallated catechins was favored by epi-configuration but hindered by pyrogallol moiety, and the hydrolysis reaction of gallated catechins was facilitated by pyrogallol moiety. Epicatechin and epigallocatechin had the lowest thermostabilities due to epimerization and oxidation/condensation reactions respectively. Sufficient O 2 was not a precondition for the occurrence of chemical conversions of catechins under heat treatment. Non-enzymatic oligomerization occurred to epi type catechins and catechin under heat treatment, and dehydrodicatechins A were mainly responsible for the browning of epicatechin and catechin solutions. The evidence of generation of catechin oligomers provides a novel way to explain sensory change of tea and relevant products during thermal processing.
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Food & Function
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2015
·Vol. 6
·期 6
·2008-2016
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IF 2.791
Liang Zeng,Jingna Yan,Liyong Luo,Dongying Zhang
Disorders of blood lipid metabolism are the primary risk factors for many diseases. Recently, the effect of Pu-erh tea on blood lipid metabolism has received increasing attention. However, the mechanism underlying its ability to regulate blood lipid metabolism is unclear. We set out to study this through assessing the effects of Pu-erh tea aqueous extract (PTAE) on the central enzymes of blood lipid metabolism, including lipoprotein-associated phospholipase A2 (Lp-PLA2), lecithin: cholesterol acyltransferase (LCAT), 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) and pancreatic lipase (PL). We find that the Lp-PLA2, HMRG and PL activities are inhibited by PTAE in a dose-dependent manner and that the LCAT activity tends to increase with increasing PTAE concentrations. Lineweaver–Burk plot analyses reveal that PTAE acts as a competitive inhibitor for HMGR and PL and as a noncompetitive inhibitor for Lp-PLA2. Moreover, we determine that its active ingredients include catechins, gallic acid, caffeine, free amino acids, and soluble sugar. However, the effect of each ingredient and whether any of them have synergistic effects are still unknown. The results suggest that Pu-erh tea has a potent ability to regulate blood lipid metabolism and knowledge of the mechanisms provides insights into its potential therapeutic application as an alternative hypolipidemic drug.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2013
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IF 2.596
Yuanfeng Wang,Yangyang Liu,Jianglei Huo,Tingtong Zhao,Jian Ren,Xinlin Wei
Four polysaccharides (TPS-F, TPS-V, TPS-S and TPS-M) were obtained from tea ( Camellia sinensis ) leaves by freeze-drying, vacuum-drying, spray-drying and microwave-vacuum drying, respectively. Their chemical composition and biological properties were comparatively studied. The results showed these TPS were similar in IR, UV absorption and distribution of molecular weight. However, they showed significant differences ( P < 0.05) in yields of crude polysaccharides and contents of protein and total polyphenols. Furthermore, morphological analysis showed their surface differed from each other in size and shape when viewed by SEM, from which surface of TPS-F was rough and porous, surface of TPS-S was evenly particles, and surfaces of the other two were similar to anomalistic bricks. In addition, the bioactivity of them was also evaluated. It was found TPS-F exhibited relatively better ability on metal chelating and superoxide radicals scavenging assays than others, and TPS-V exhibited higher ability on α-glycosidase and α-amylase inhibition assays than others with inhibitory percentages of 82.75% and 92.8%.
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Journal of Oleo Science
·
2017
·
IF 1.076
Yating Zhang,Lingbiao Gu,Fei Wang,Lingjun Kong,Huili Pang,Guangyong Qin
We specially carried out the subcritical butane extraction to separate abamectin from tea leaves. Four parameters, such as extraction temperature, extraction time, number of extraction cycles, and solid-liquid ratio were studied and optimized through the response surface methodology with design matrix developed by Box–Behnken. Seventeen experiments with three various factors and three variable levels were employed to investigate the effect of these parameters on the extraction of abamectin. Besides, catechins, theanine, caffeine, and aroma components were determined by both high-performance liquid chromatography and gas chromatography–mass spectrometry to evaluate the tea quality before and after the extraction. The results showed that the extraction temperature was the uppermost parameter compared with others. The optimal extraction conditions selected as follows: extraction temperature, 42°C; number of extraction cycles and extraction time, 1 and 30 min, respectively; and solid–liquid ratio, 1:10. Based on the above study, the separation efficiency of abamectin was up to 93.95%. It is notable that there has a quite low loss rate, including the negligible damage of aroma components, the bits reduce of catechins within the range of 0.7%–13.1%, and a handful lessen of caffeine and theanine of 1.81% and 2.6%, respectively. The proposed method suggested subcritical butane possesses solubility for lipid–soluble pesticides, and since most of the pesticides are attached to the surfaces of tea, thus the as-applied method was successfully effective to separate abamectin because of the so practical and promising method.
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Food Chemistry-X
·
2025
·
IF 8.2
Jian Ouyang,Ronggang Jiang,Huimin An,Xingchang Ou,Jing Wang,He Xie,Wenjie Fu,Jing Zhang,Hongyu Chen,Qi Liu,Juan Li,Haitao Wen,Ligui Xiong,Jian-an Huang,Zhonghua Liu
Rucheng Baimaocha ( Camellia pubescens ) black tea (RCBT) exhibits floral and sweet attributes with a unique minty-like aroma, distinguishing it from traditional and other innovative black teas. However, its key odorants remain unknown. In this study, gas chromatography-olfactometry (GC-O) combined with aroma extraction dilution analysis detected 26 aroma-active compounds (ACCs), of which 20 ACCs were quantified as odorants of RCBT infusion. In addition, aroma recombination models well simulated the overall aroma characteristics of RCBT infusion, which proved the accuracy of identification and quantification. Omission experiments showed that 12 key odorants played crucial roles in aroma formation of RCBT. Among these, four odorants (methyl salicylate, ( E , Z )-2,6-nonadienal, methyl geranate, and ( E )-2-nonenal), were of great importances for unique minty-like aroma, with significantly higher concentrations compared to other black tea varieties. This study offered a foundational theoretical framework for the processing and quality control of RCBT.
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Advanced Therapeutics
·
2024
·
IF 3.7
Kang Hu,Zhuo Huang,Qinying Tang,Danyang Chen,Lianxu Chen,Lu Chen,Guohua Jiang,Qianfei Huang,Langjie Chai,Hang Chen,Liang Guo,Bin Li
Currently, searching for safer and more effective approaches to promote skin wound healing and tissue regeneration is a significant research focus in the field of public health. Eliminating excessive reactive oxygen species (ROS) and using electrically active dressings to accelerate wound healing has gained significant attention. Herein, green tea-based carbon dots (GCDs) are synthesized from leaves of green tea and proven to possess strong antioxidant, antibacterial, and anti-inflammatory properties. Then, GCDs, polyvinyl alcohol (PVA), and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) are successfully constructed into a multifunctional conductive PVA-PEDOT:PSS/GCDs hydrogel (PPPCD) using a repeated freeze-thaw method for promoting skin wound healing. Highly electrical conductivity is imparted by introducing PEDOT:PSS, while antioxidant and antibacterial properties are conferred by GCDs. In vitro assays demonstrated the excellent biocompatibility of the hydrogel, as well as its ability to scavenge excessive ROS and promote cell migration. Furthermore, the hydrogel not only accelerates wound healing by promoting blood vessel formation and epidermal regeneration but also alleviating excessive inflammation in vivo. Overall, the developed hydrogel dressing demonstrates promising prospects for skin wound healing and offers a new perspective for tissue engineering.
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FOOD RESEARCH INTERNATIONAL
·
2025
·
IF 8
Yingbin Zhang,Xuwei Chen,Dingding Chen,Li Zhu,Guoqing Wang,Zhongxiu Chen
The taste of Chinese green tea is highly diverse. In this study, a combination of unsupervised and supervised learning methods was utilized to develop a model for classifying and predicting typical Chinese green tea taste. Three clustering methods were assessed based on quantitative descriptive analysis (QDA) results, with the Hierarchical-K means method chosen to classify 88 tea infusions into seven distinct taste types. Electronic tongue sensors, near-infrared spectroscopy, and metabolomics, along with the analysis of key chemical constituents, were applied to construct various datasets as model data. The performance of four multivariate statistical methods and six artificial intelligence algorithms was compared across the three datasets. Dataset 3, comprising chemical components, taste activity value (Tav), and their ratios, achieved the highest accuracy. The random forest (RF) model achieved the highest accuracy (0.98) and Kappa value (0.97) in predictions. The results indicate that key chemical components, Tav, and their relationships are more critical for classifying green tea taste. This study can provide a more accurate representation and prediction of typical Chinese tea taste profiles from a consumer standpoint. Significant variations in sensory attributes and chemical composition were observed among the identified taste categories, with the MU type displaying the lowest TavTC (total Tav of catechins)/TavTAA (total Tav of amino acids) ratio, indicating the strongest umami and sweetness characteristics. The findings of this study offer the potential for the development of personalized tea products, thereby contributing to an enhanced consumer experience.
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FOOD RESEARCH INTERNATIONAL
·
2024
·
IF 7
Dongzhu Huang,Chenyi Sun,Yuhan Wu,Fangling Zheng,Qiqi Yang,Xinmeng Zhang,Qianying Dai,Xiaochun Wan,Qi Chen
This study aimed to investigate the effect of the combination of shaking and various anaerobic treatments on the aroma quality of gabaron oolong tea (GAOT) by chemical and sensory evaluation. The results showed that elevated anaerobic treatment harmed GAOT aroma, emphasizing undesirable attributes such as earthy, fatty, etc. A total of 85 volatiles were identified by gas chromatography-ion mobility spectrometry (GC-IMS), and the relationship between aroma attributes and volatiles were revealed by PLS regression projection and correlation network. Hexanal and octanal at inappropriate concentrations were main causes to the earthy attribute, while nonanal exhibited a potential masking effect against unpleasant attributes. Addition experiments and σ-τ plot analysis verified these associations. Furthermore, observing dynamic patterns of content changes of these three aldehydes in fresh leaves prior to tea thermal processing, providing references for future process optimization. These results provide a new direction for enhancing the quality of GAOT.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2024
·
IF 5.8
Kuikun Gu,Xinyue Du,Xueying Song,Yu Wang,Zhongbao Luo,Xiaodong Yang,Mingzhe Zhang
The ternary metal oxides that combine two different metal cations is an interesting candidate as sensing material based on their interesting properties. Hence, ordered dendrite InWO 4 was successfully synthesized via a hydrothermal method, followed by the construction of an InWO 4 -rGO heterojunction to enhance detection capability for triethylamine (TEA) gas. The synthesized product underwent morphology and elemental composition analysis using various techniques. Gas sensing experiments revealed that the InWO 4 -rGO gas sensor, operating at the optimal temperature of 220 ℃, displayed a significantly improved response to 100 ppm TEA, with a high value of 59.5, in comparison to the pure InWO 4 gas sensor (11.5 at 250 ℃). Additionally, the recovery time was reduced from 184 s to 122 s. Based on experimental data and gas sensing reaction theory, this study attributes the improved gas sensing performance to the formation of p-n heterojunction, a larger specific surface area and rGO's catalytic effect. This study not only introduces a novel addition to the gas sensing material family but also promotes the development of advanced gas sensors.
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JOURNAL OF FOOD SCIENCE
·
2024
·Vol. 89
·期 11
·7803-7818
·
IF 3.2
Jianfeng Zhou,Weiqiang Wang,Xingjian Yang,Deng-Guang Yu,Ping Liu
Bio-based active food packaging materials have a high market demand. We use coaxial electrospinning technology to prepare core–shell structured nanofibers with sustained antibacterial and antioxidant properties. The fiber core layer was composed of gelatin and tea polyphenols, whereas tea polyphenols provide antibacterial and antioxidant properties; the fiber sheath was composed of pullulan polysaccharides with antioxidant properties. By using a scanning electron microscope, it can be seen that the diameter distribution of the prepared nanofibers was uniform and the surface is smooth; using a transmission electron microscope, it can be clearly seen that the nanofibers have a core–shell structure; Fourier Transform Infrared and X-ray diffraction analysis indicate that the nanofibers have an amorphous structure; the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging shows that nanofibers have higher antioxidant properties with the addition of tea polyphenols; antibacterial test showed that nanofibers had obvious inhibitory effect on the growth of Staphylococcus aureus and Escherichia coli ; and the nanofiber film dissolution test shows that nanofibers can be used as fast soluble active packaging. Finally, core–sheath-structured nanofibers can serve as active packaging for instant food, possessing both rapid water solubility and excellent antibacterial and antioxidant activity, making water-soluble nanofibers interesting applications in the field of food packaging.
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ACS Biomaterials Science & Engineering
·
2024
·
IF 5.4
Jialuo Chen,Zhipeng Li,Xinpeng Chen,Yurong Sun,Jin Cheng,Aijing Li,Shenzhou Lu,Tieling Xing
Adhesives have garnered significant interest recently due to their application in the field of biomedical applications. Nonetheless, developing adhesives that exhibit robust underwater adhesion and possess antimicrobial properties continues to pose a significant challenge. In this study, motivated by the adhesive mechanism observed in mussels in aquatic environments, dopamine (DA) was added to modify the silk fibroin (SF) solution. Subsequently, tea polyphenol (TP) was incorporated to form a sticky mixture, resulting in a biomimetic adhesive (TP-DA/SF). TP-DA/SF demonstrated rapid, robust, and indiscriminate adhesion to a wide array of substrates and even biological tissues (39 kPa). TP-DA/SF exhibits the ability to replicate the mussel adhesion mechanism of mussels underwater thanks to its biomimetic design. This characteristic provides the material with robust adhesion (40 kPa), notable reusability (at least 10 times), and long-lasting stability, especially in aquatic settings. It is worth noting that TP-DA/SF also demonstrated high adhesion in various water environments, even in solutions with a pH of 7.4 and buffered saline (PBS), which is one of the most widely used buffers in biochemistry research, offering salt-balancing and adjustable pH buffering capabilities. Meanwhile, TP-DA/SF exhibits excellent antibacterial and antioxidant properties due to its tea polyphenol content. After 15 days of wound closure in SD rats, the healing rate in the experimental group reached 93.4%, compared to 83.9% in the control group. Thus, the TP-DA/SF adhesive holds promising potential for biomedical applications, including sutureless wound closure and tissue adhesion.
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CELLULOSE
·
2024
·
IF 4.9
Liu Huijun,Chen Li,Peng Yan,Li Xia,Zhang Haiqiang,Chen Yanhao,Li Zhi,Dai Fangyin
Hydrogels can relieve wound pain and provide a moist environment for wound healing. Although hydrogels based on natural materials have proven to be biocompatible and biodegradable, their antibacterial and anti-inflammatory properties are not desirable. Natural extracts with antimicrobial and antioxidant properties are becoming increasingly attractive because of their environmentally friendly nature and good biocompatibility. Herein, composite cellulose/silk fibroin/polyacrylic acid hydrogels based on natural materials were fabricated by crosslinking between oxidized cellulose and silk fibroin together with radical polymerization of acrylic acid. The fabricated hydrogels displayed a uniform hierarchical topography with high porosity, as well as good mechanical properties, swelling properties, air permeability and biocompatibility. With the addition of tea polyphenols to natural extracts, the composite hydrogels exhibited significant antimicrobial and antioxidant properties such that they could prevent bacterial infection and relieve wound inflammation in the inflammation stage and could promote the synthesis of extracellular matrix (ECM), angiogenesis, collagenization and re-epithelization during wound healing. The tea polyphenols/cellulose/silk fibroin/polyacrylic acid hydrogels fabricated in this study can accelerate wound healing, demonstrating their great potential for application in wound dressings.
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