FOOD CHEMISTRY
·
2021
·
IF 7.514
Jinghui Zhou,Changwei Liu,Shimin Zhao,Ya Liu,Sheng Zhang,Qiang Zhao,Fen Wang,Gang Xu,Jianan Huang,Zhonghua Liu
Theaflavin-3,3ʹ-digallate (TFDG) in black tea possesses several health benefits. However, low TFDG yields limit its application. Herein, tyrosinases from Bacillus megaterium (Bmtyrc) were used to synthesize TFDG. To improve the catalytic efficiency of tyrosinase, a directed evolution strategy and a high-throughput screening method was employed. Compared with the wild type, mutant Bmtyrc-3 (N205D/D166E/D167G/F197W) showed 6.46 and 4.91-folds higher specific activity and 51.97- and 1.95-folds higher Vmax values towards epigallocatechin gallate (EGCG) and epicatechin gallate (ECG), respectively. Moreover, Bmtyrc-3 displayed significantly enhanced catalytic efficiencies, and the space–time yield of TFDG was 35.35 g L -1 d -1 . Bmtyrc-3 presents a broader substrate binding area, caused by a mutation (N205D) encompassing the active site. Changes in the potential of the substrate binding site and hydrogen bonds, and the electrostatic effect on the protein surface resulted in an increased activity of the substrates EGCG and ECG.
研究领域:
生物技术
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生物化学
·
酶学
·
食品科学
✓ 已验证
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2019
·
IF 5.399
Yinyin Liao,Xiumin Fu,Haiyun Zhou,Wei Rao,Lanting Zeng,Ziyin Yang
Although specialized metabolite distributions in different tea ( Camellia sinensis ) tissues has been studied extensively, little is known about their within-tissue distribution owing to the lack of nondestructive methodology. In this study, desorption electrospray ionization imaging mass spectrometry was used to investigate the within-tissue spatial distributions of specialized metabolites in tea. To overcome the negative effects of the large amount of wax on tea leaves, several sample preparation methods were compared, with a Teflon-imprint method established for tea leaves. Polyphenols are characteristic metabolites in tea leaves. Epicatechin gallate/catechin gallate, epigallocatechin gallate/gallocatechin gallate, and gallic acid were evenly distributed on both sides of the leaves, while epicatechin/catechin, epigallocatechin/gallocatechin, and assamicain A were distributed near the leaf vein. L -Theanine was mainly accumulated in tea roots. L -Theanine and valinol were distributed around the outer root cross-section. The results will advance our understanding of the precise localizations and in-vivo biosyntheses of specialized metabolites in tea.
研究领域:
植物科学
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分析化学
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代谢组学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
·
2022
·Vol. 103
·期 8
·3896-3906
·
IF 4.125
Xinyue Hong,Xin Song,Xiaqing Wu,Change Yang,Deming Gong,Guowen Zhang
BACKGROUND Gallocatechin gallate (GCG), a catechin of tea polyphenols, possesses inhibitory ability against tyrosinase, but few studies have reported how common processing methods affect it. In this research, the influence of heating and ultrasound treatments on the inhibition of GCG against tyrosinase was explored by ultraviolet–visible absorption, fluorescence spectroscopy, high-performance liquid chromatography and liquid chromatography–tandem mass spectrometry. RESULTS Both heating and ultrasound treatments of GCG alone improved GCG's inhibitory ability against tyrosinase compared with the untreated, and a combination of heating and ultrasound treatment (100 °C, 20 min + 630 W, 20 min) further decreased the relative tyrosinase activity to 26.8%. The treated GCG exhibited a stronger fluorescence quenching effect on tyrosinase, but did not have any influence on the static quenching mechanism. Compared to the untreated GCG, the binding constants of treated GCG by heating, ultrasound and their combination with tyrosinase significantly increased, but the number of binding sites was still approximately one and the main driving force of the treated GCG was still hydrophobic interaction. After treatments of heating, ultrasound and their combination, the composition of GCG solutions was changed. CONCLUSION The enhanced inhibition of treated GCG on tyrosinase may be due to partial conversion of GCG into epigallocatechin-3-gallate (EGCG) and gallic acid (GA), which may cooperate with GCG to better inhibit the enzyme activity. This study has provided some valuable information for the application of catechins against tyrosinase in food processing and cosmetic industry. © 2022 Society of Chemical Industry.
研究领域:
食品科学
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化妆品化学
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生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2020
·
IF 6.306
Yu-gang Shi,Run-run Zhang,Chen-min Zhu,Ming-feng Xu,Qing Gu,Rammile Ettelaie,Shan Lin,Yi-fan Wang,Xin-yi Leng
The objective of this study was to investigate the antibacterial activity and potential mechanism of alkyl gallates against Escherichia coli and Staphylococcus aureus . Results show that the length of the alkyl chain plays a pivotal role in eliciting the activity and octyl gallate (OG) exerted excellent bactericidal activity through a multiple bactericidal mechanism. OG functions against both bacteria through damaging bacterial cell wall integrity, permeating into cells and then interacting with DNA, as well as disturbing the activity of the respiratory electron transport chain to induce a high-level toxic ROS (hydroxyl radicals) generation and up-regulation of the ROS genes. Also, electrospun nanofibers with OG have unique superiorities for maintaining the freshness of the icefish (4 °C). This research not only provides a more in-depth understanding of the interaction between OG and microorganisms but also highlights the great promise of using OG as a safe multi-functionalized food additive for food preservations.
研究领域:
食品科学
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微生物学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Xiaohong Hu,Jia Wen,Haibo Zhang,Qian Wang,Caiya Yan,Lang Xing
The most important thing to do with hexavalent chromium (Cr(VI)) removal in wastewater through adsorption-reduction method is to find an adsorbent that has both strong adsorbability and reducibility. Herein, an eco-friendly material ZIF-8-EGCG, which was a combination of epicatechin gallate (EGCG) and ZIF-8, was synthesized to treat Cr(VI)-containing wastewater. At room temperature, the maximum adsorption amount of Cr(VI) reached 136.96 mg·g −1 , and the Cr(VI) reduction rate (96%) was much better than that of the original ZIF-8 (37%). Such outcome was among the best in the existing studies using MOFs to treat Cr(VI). In addition, the characterization results showed that the surface of ZIF-8-EGCG was electronegative. The material was irregular sphere with pore size of 7.12 nm and BET surface area of 113.02 m 2 ·g −1 . The well-fitted Langmuir adsorption isotherm and pseudo first/second-order kinetics model suggested that the adsorption of Cr(VI) on ZIF-8-EGCG was governed by both physical and chemical processes. Stability results revealed that the overall stability of ZIF-8-EGCG due to the etched structure was slightly inferior to ZIF-8, especially at higher temperatures (>35 °C). Simultaneously, the reaction between ZIF-8-EGCG and Cr(VI) was a spontaneous, exothermic, entropic decrease process.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
·
2019
·Vol. 55
·期 4
·1531-1538
·
IF 2.281
Yangping Ding,Bingcan Chen,Huayi Suo,Huarong Tong
Summary Theaflavin-3,3′-digallate (TFDG) is the main product formed by oxidative condensation between (−)-Epigallocatechin-3-gallate (EGCG) and (−)-Epicatechin-3-gallate (ECG). Some sub-products, such as homo- and hetero-oligomers of EGCG and ECG, are also produced simultaneously, which significantly decreases the yield of TFDG. In general, the optimum temperature for TFDG synthesis is 20 °C below which can reduce its generation resulting in the coexistence of a large amount of unreacted substrates (ECG and EGCG). Therefore, a higher possibility of increasing the formation of TFDG could be achieved if a suitable synthetic method can be developed at a low temperature. Our results showed that simultaneous dropwise addition of both EGCG and ECG could markedly enhance the content of TFDG at ice bath. Using such technique, the production of TFDG increased by 47.60% as compared to the group synthesised under the optimum temperature. The absorbance of TFDG at 278 nm is 2.36 times higher than that of ECG with equimolar concentration. Therefore, a rapid, simple and accurate calculation method of TFDG yield was developed via the spectral correlation. Based on the counting method, the yield of TFDG was 30.58% by using the novel synthetic method of TFDG.
研究领域:
食品科学
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植物化学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2022
·
IF 8.025
Wangli Dai,Chen Yan,Yicheng Ding,Wenjie Wang,Saiqi Gu,Zheng Xu,Xuxia Zhou,Yuting Ding
The objective of this study was to investigate the potential application of chitosan coatings incorporating epigallocatechin gallate (EGCG) for preserving fillets of bighead carp during chilled storage. The fillets were coated with acetic acid and glycerol, chitosan, and chitosan-EGCG, respectively, and the changes in their physicochemical, microbiological, and sensory characteristics during storage at 4 °C were determined. Notably, total volatile basic nitrogen, thiobarbituric-acid-reactive substances, and K value of chitosan-EGCG coated fillets sampled on day 15 were 48.04 %, 60.19 %, and 32.91 % lower than untreated fillets, respectively. Microbial enumeration suggested that the inclusion of EGCG significantly improved the inhibitory effect of pure chitosan coating on the proliferation of microorganisms. Furthermore, the chitosan-EGCG coated fillets also performed the best in terms of color, texture, and sensory analysis, and extended the shelf-life of the fillets for at least 6 days. A principal component analysis further confirmed the preserving effect of the chitosan-EGCG coating. Mantel test results suggested that the fillets' organoleptic characteristics strongly correlated with physicochemical and microbiological indicators. Overall, this work provides an effective protocol for food quality control and the extension of shelf life during chilled storage, and it clarifies the relationships between organoleptic characteristics and physicochemical and microbiological indexes.
研究领域:
食品科学
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生物化学
✓ 已验证
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2016
·
IF 3.138
Shicheng Lei,Minhao Xie,Bing Hu,Li Zhou,Yi Sun,Muhammad Saeeduddin,Hongcheng Zhang,Xiaoxiong Zeng
In the present study, pear polyphenol oxidase (PPO) was purified, immobilized and applied for the synthesis of theaflavin-3,3′-digallate (TF3). Firstly, PPO of pear ( Pyrus bretschneideri Rehd cv. Huangguan) was purified 24.36-fold in specific activity with a recovery of 6.77% by sequential use of precipitation with 70% saturated ammonium sulfate and chromatography of DEAE-Sepharose Fast Flow column. The purified pear PPO, found to be a dimer of identical subunits of molecular mass 35 kDa, was then successfully immobilized onto Fe 3 O 4 /chitosan nanoparticles via glutaraldehyde coupling reaction. Finally, TF3 was effectively synthesized by applying the immobilized PPO as biocatalyst with epicatechin gallate (ECG) and epigallocatechin-3- O -gallate (EGCG) as substrates, and the maximum yield of TF3 was 42.23% based on the amount of ECG added. In addition, the immobilized enzyme still remained 85% of its initial ability after successive usage of 8 cycles and could be stored for 30 days with less loss of activity. All the results suggest that the developed procedure is quite useful and has great potential for synthesis of TF3 and other theaflavins.
研究领域:
食品科学
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酶工程
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植物学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF FOOD SCIENCE
·
2022
·Vol. 87
·期 7
·3013-3025
·
IF 3.693
Ping Chen,Pengkai Wang,Pengzhi Hong
In this study, pectin was modified with ferulic acid (Fa), trans -ferulic acid ( trans -Fa), methyl gallate (MG), and ethyl gallate (EG) via the enzymatic method using aqueous/organic phases to enhance its physiochemical and bio-active properties. Results revealed that lipase might catalyze the hydrolysis of the ester bond within pectin in aqueous phase and prompt the transesterification between the hydroxyl group in the para position in Fa/ trans -Fa or the 2′-OH group of MG/EG and the carboxylic group of pectin in the organic phase. The graft ratio was 21.00%, 21.67%, 13.24%, and 11.93% for the Fa-, trans -Fa-, MG-, and EG-modified pectin, respectively. In addition, compared with native pectin, the modified pectin exhibited improved apparent viscosity and emulsion activity. Moreover, the clearance of 1,1-diphenyl-2-picryl hydrazine (DPPH) and 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) was effectively enhanced for the modified pectin. Furthermore, the modified pectin exhibited strong antibacterial activity against Escherichia coli and Staphylococcus aureus while no cytotoxic effects based on the results of cell culture experiments. Our results provide a theoretical basis for the expansion of pectin applications in the food and pharmaceutical industries.
研究领域:
食品科学
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生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TALANTA
·
2024
·
IF 5.6
Guangxuan Chen,Huicong Yuan,Lumei Zhang,Jingran Zhang,Kefeng Li,Xu Wang
The discovery of pancreatic lipase (PL) inhibitors is an essential route to develop new anti-obesity drugs. In this experiment, chitosan was used to add amino groups to cellulose filter paper (CFP) and then glutaraldehyde was used to covalently combine PL with amino-modified CFP through the Schiff base reaction. Under optimal immobilization conditions, CFP immobilized PL has a wide range of pH and temperature tolerance, as well as excellent reproducibility, reusability and storage stability. Subsequently, 26 natural products (NPs) were screened by immobilized PL with black tea extract having the highest inhibition rate. Three compounds with binding effects on PL (epigallocatechin gallate, theaflavin-3-gallate and theaflavin-3,3′-digallate) were captured. Molecular docking proved that these three compounds have a strong binding affinity for PL. Fluorescence spectra further revealed that theaflavin-3,3′-digallate could statically quench the intrinsic fluorescence of pancreatic lipase. The molecular docking and thermodynamic parameters indicated that electrostatic interaction was considered as the main interaction force between PL and theaflavin-3,3′-digallate. Finally, the potential anti-obesity targets and pathways of the three compounds were discussed through network pharmacology. This study not only proposes a simple and efficient method for screening PL inhibitors, but also sheds light on the anti-obesity mechanism of active compounds in black tea.
研究领域:
药理学
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生物化学
·
分子生物学
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食品科学
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生物技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Food Biophysics
·
2022
·Vol. 17
·期 4
·598-611
·
IF 3.34
Yang Pan-pan,Shi Yu-gang,Li Dong-hui,Chen Ru-kang,Zheng Mei-zhi,Ma Kai-zhi,Xu Nuo,Dong Li-juan,Li Teng
To guarantee the safety and quality of food and prolong its shelf life, a novel multi-functionalized chitosan-based film with the outstanding antimicrobial property was prepared by incorporating with β -cyclodextrin ( β CD) and octyl gallate (OG). The OG encapsulation with β CD to form inclusion complexes ( β CD/OG-IC) endows OG with improved water-solubility and physicochemical stability. The formation of β CD/OG-IC has been proved through analytical techniques including FTIR, XRD, DSC and 1 H NMR. Then the chitosan (CS) films containing β CD/OG-IC were fabricated and their mechanical, physical properties and antimicrobial activities against four foodborne pathogens ( E. coli , S. aureus , L. monocytogenes and P. fluorescens ) were evaluated. The increased antibacterial activities of the CS film containing β CD/OG-IC were demonstrated by measuring the diameter of the inhibition zone. Meanwhile, the composite films showed higher tensile strength, more excellent water vapor resistance in contrast to pure CS films. Additionally, the composite films showed slow-release capacity and enhanced antibacterial efficacy to remarkably extend the shelf life of blueberry and asparagus. Our results substantially suggest that CS film containing β CD/OG-IC is a potential candidate for use as a multi-functionalized layer in the food-packaging system.
研究领域:
食品科学
·
材料科学
✓ 已验证
DOI
高影响因子
FOOD RESEARCH INTERNATIONAL
·
2024
·
IF 7
Dong Cai,Xinmiao Wang,Qian Wang,Peiyong Tong,Weiyuan Niu,Xu Guo,Jinghan Yu,Xuan Chen,Xiaoyang Liu,Dayong Zhou,Fawen Yin
The β-cyclodextrin and short-chain alkyl gallates (A-GAs), which are representative of phenolipids, such as butyl, propyl, ethyl, and methyl gallates, were chosen to form inclusion complexes by the use of the freeze-drying process. In the everted rat gut sac model, HPLC-UV analysis demonstrated that the released A-GAs from inclusion complexes were degraded to yield free gallic acid (GA) (sustained-release function 1). The small intestine membrane may be crossed by both the GA and the A-GAs. A-GAs may also undergo hydrolysis to provide GA (sustained-release function 2) following transmembrane transfer. Clearly, a helpful technique for the dual sustained-release of phenolic compounds is to produce β-cyclodextrin inclusion complexes with short-chain phenolipids. This will increase the bioactivities of phenolic compounds and prolong their in vivo residence length. Moreover, changing the carbon-chain length of these β-cyclodextrin inclusion complexes would readily modify the dual sustained-release behavior of the phenolic compounds. Thus, our work effectively established a theoretical foundation for the use of β-cyclodextrin inclusion complexes containing short-chain phenolipids as new source of functional food components to provide the body with phenolic compounds more efficiently.
研究领域:
食品科学
·
药理学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）