LWT-FOOD SCIENCE AND TECHNOLOGY
·
2023
·
IF 6
Dahe Qiao,Junyan Zhu,Xiaozeng Mi,Hui Xie,Mingtao Shu,Minyi Chen,Rui Li,Shengrui Liu,Chaoling Wei
Withering time of fresh leaves is a key factor affecting the stability of flavor quality of Taiping Houkui tea (TPHK). It's effect and mechanism on the formation of flavor in TPHK remain unelucidated. Here, metabolomics and transcriptomics were combined to comprehensively investigate changes in the main flavor compounds and the expression patterns of related genes under different withering times. The results showed that withering had the greatest influence on the content of most amino acids and aroma volatiles. The relative content of most volatiles was observed to be highest at 6–8 h of withering time, which was consistent with the results from the sensory evaluation of aroma quality. Plant hormone signal transduction pathways played a key role in the variation of the flavor compound content under different withering times, especially ABA and JA signals. WGCNA demonstrated that ABA, JA, IAA, SA and different flavor substances were significantly associated with specific modules. JA may be involved in the metabolism of theanine during withering, while ABA may be involved in the accumulation of aromatic amino acids and main aroma components of TPHK. This research may serve as a reference for the optimization of the processing technology for TPHK.
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL DAIRY JOURNAL
·
2023
·
IF 3.1
Hongbo Li,Meng Bian,Yuelu Jiang,Chunshuang Li,Yang Zou,Xiaohong Chen,Hongjuan Li,Jinghua Yu
To better monitor and reduce the generation of Maillard reaction products (MRPs) during the heat treatment and storage of dairy products , a reaction kinetic model was established to evaluate the inhibitory effects of tea polyphenols on MRPs in the milk simulation system. The inhibition of MRPs by tea polyphenols followed first order kinetics, while the inhibition of 5-hydroxymethyl-2-furfural (5-HMF) was most pronounced at 95 °C with the reaction rate constant of −0.0683 d −1 . Arrhenius model showed that the conversion rate of 5-HMF (35.672 d −1 ) was higher than N ε -carboxyethyllysine (2.585 d −1 ) and N ε -carboxymethyllysine (0.53 d −1 ) after the addition of tea polyphenols, which indicated that 5-HMF was the main intermediate product of Maillard reaction. Moreover, the shelf life of the two-stage sterilised milk containing tea polyphenols was 141 d, which was 2.1 times longer than that of the control sample (67 d), which provided reference for consumers during the drinking period.
✓ 已验证
DOI
高影响因子
FOOD SCIENCE AND BIOTECHNOLOGY
·
2023
·
IF 2.9
Chen Xiaoqiang,Chen Tingting,Liu Jiayan,Wei Yan’an,Zhou Weilong
Tea polyphenols were used as substrates and oxidized successively by polyphenol oxidase and peroxidase to prepare theabrownins (TBs-dE). The conversion rate of catechins to TBs-dE was 90.91%. The ultraviolet and infrared spectroscopic properties and zeta potential of TBs-dE were characterized. TBs-dE is more stable at pH 5.0–7.0, about 25 °C or in dark environment. Ultraviolet light and sunlight can deepen its color due to the further oxidative polymerization. Mg 2+ , Cu 2+ , and Al 3+ had a significant effect on the stability of TBs-dE. The inhibitory rates of TBs-dE (1 mg/mL) against Staphylococcus aureus and Escherichia coli DH5α were 51.45% and 45.05%, respectively. After TBs-dE treatment, the cell morphology of both bacteria changed, some cell walls were blurred, and the cytoplasmic content leaked. The research results can provide theoretical support for the industrialization of theabrownins.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
AQUATIC TOXICOLOGY
·
2023
·
IF 4.5
Yitong Lu,Xinxin Jiang,Hongzhou Xu,Chengrong Liu,Yanzhen Song,Kuiquan Pan,Lixin Wang,Liang Du,Haixia Liu
Global warming has increased the frequency of Microcystis aeruginosa blooms, leading to the deterioration of water quality and loss of biodiversity. Therefore, developing effective strategies for controlling M. aeruginosa blooms has become an important research topic. Plant extracts, 4‑tert-butylpyrocatechol (TBC) and tea polyphenol (TP) are commonly used for water purification and to increase fish immunity, which have great potential to inhibit cyanobacterial blooms. The inhibitory effects of TBC and TP on M. aeruginosa were investigated in terms of growth characteristics, cell membrane morphology, physiological, photosynthetic activities, and antioxidant enzymes activities . The results showed that TBC and TP inhibited the growth of M. aeruginosa by decreasing the chlorophyll fluorescence transients or increasing the antioxidant enzymes activities of M. aeruginosa . TBC damaged the cell morphology of M. aeruginosa , reduced extracellular polysaccharides and protein contents, and up-regulated the antioxidant activity-related gene ( sod and gsh ) expressions of M. aeruginosa . TP significantly decreased the photosynthetic pigment content, influenced the phycobiliprotein content, and strongly down-regulated the photosynthesis-related gene ( psbA, psaB, and rbcL ) relative expressions of M. aeruginosa . TBC caused significant oxidative stress , dysfunction of physiological metabolic processes, and damaged crucial biomacromolecules (e.g., lipids, proteins and polysaccharides), prompted the loss of cell integrity, ultimately leading to the death of M. aeruginosa . However, TP depressed photosynthetic activities and consequently inhibited the transfer of electrons, affected the electron transfer chain , decreased the photosynthetic efficiency , and eventually caused the death of M. aeruginosa cells. Our study showed the inhibitory effects and algicidal mechanisms of TBC and TP on M. aeruginosa , and provide a theoretical basis for restrain the overgrowth of M. aeruginosa .
✓ 已验证
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2023
·
IF 8.2
Mengyao Liu,Shan Shan,Xin Gao,Yudong Shi,Weihong Lu
In this study, we investigated the effect of sweet tea polysaccharide (STP) on the physicochemical and structural properties of heat-induced whey protein isolate (WPI) gels, and explored the potential mechanism. The results indicated that STP promoted the unfolding and cross-linking of WPI to form a stable three-dimensional network structure, and significantly improved the strength , water-holding capacity and viscoelasticity of WPI gels. However, the addition of STP was limited to 2 %, too much STP would loosen the gel network and affect the gel properties. The results of FTIR and fluorescence spectroscopy suggested that STP affected the secondary and tertiary structures of WPI, promoted the movement of aromatic amino acids to the protein surface and the conversion of α-helix to β-sheet. In addition, STP reduced the surface hydrophobicity of the gel, increased the free sulfhydryl content, and enhanced the hydrogen bonding, disulfide bonding , and hydrophobic interactions between protein molecules . These findings can provide a reference for the application of STP as a gel modifier in the food industry.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Ming Liu,Mei Lin,Pan Wu,Gary Owens,Zuliang Chen
A green tea extract was used as a natural reducing agent to prepare three different manganese oxides (Mn 3 O 4 , Mn 2 O 3 and MnO) which after carbonization in different atmospheres, were evaluated for their ability to degrade estriol (E3). Catalytic ability of the three manganese oxides varied in the order Mn 2 O 3 > Mn 3 O 4 > MnO; corresponding to E3 degradation efficiencies of 100, 100 and 92.5 % after 180 min. After calcination, no new functional groups were observed on the surface of three manganese oxides, except the corresponding spectra. The morphology of the manganese oxides was primarily olive-shaped, with numerous small cubic particles stacked at the nanoscale, with a uniform distribution of elements. Free radicals and Mn ion leaching was observed from the prepared manganese oxides where leaching of manganese ions was related to the intensity of singlet oxygen. Advanced material characterization showed while green synthesis resulted in materials being doped with a small amounts of elements such as C and S, the broad crystal structure of the three materials was still the main factor affecting the removal efficiency of E3; with Mn(III) playing a major role in the catalytic peroxydisulfate (PDS) process.
✓ 已验证
产品关联
DOI
高影响因子
CLINICAL ORTHOPAEDICS AND RELATED RESEARCH
·
2019
·
IF 4.154
Yue Ren,Xin Wei,Song-Tao Wei,Fei-Yu Wang,Jing Wang,Jia-Zhuang Xu,Lu Xu,Rizwan M. Gul,Zhong-Ming Li
Background Synovial fluid components, especially lipids, can trigger oxidation of ultrahigh-molecular-weight polyethylene (UHMWPE) artificial joint components in vivo. The use of antioxidants such as vitamin E effectively diminishes the oxidative cascade by capturing free radicals and reducing the oxidation potential of UHMWPE implants. Using a thermo-oxidative aging method, we recently found that tea polyphenols can enhance the oxidation resistance of irradiated UHMWPE in comparison with commercial vitamin E. However, it is yet unknown whether tea polyphenols can reduce lipid-induced oxidation. Questions/purposes We explored whether tea polyphenol-stabilized UHMWPE would exhibit (1) lower squalene absorption; (2) stronger oxidation resistance; and (3) lower content of free radicals than vitamin E-stabilized UHMWPE under a physiologically-motivated in vitro accelerated-aging model. Methods Tea polyphenol (lipid-soluble epigallocatechin gallate [ ls EGCG]) and vitamin E were blended with UHMWPE powders followed by compression molding and electron beam irradiation at 100 and 150 kGy. Small cubes (n = 3, 60 mg, 4 × 4 × 4 mm 3 ) cut from the blocks were doped in squalene at 60°, 80°, 100°, and 120° C for 2 hours. Gravimetric change of the cubes after squalene immersion was measured to assess absorption. Thin films (n = 3, ∼60 μm) were also microtomed from the blocks and were doped at 120° C for 24 hours. Oxidation induction time (n = 3, 5 mg of material from the cubes) and incipient oxidation temperature (n = 3, thin films) were obtained to determine the oxidation stability. Signal intensity of the free radicals, obtained by electron spin resonance spectroscopy, was used to qualitatively rank the antioxidant ability of vitamin E and ls EGCG. Results Squalene absorption was comparable between ls EGCG/UHMWPE and vitamin E/UHMWPE at a given temperature and radiation dose. The oxidation induction time of 100 kGy-irradiated UHMWPE was increased with ls EGCG compared with vitamin E except at 120° C. For example, the oxidation induction time value of 100 kGy-irradiated ls EGCG/UHMWPE immersed at 60 o C was 25.3 minutes (24.2–27.8 minutes), which was 8.3 minutes longer than that of 100 kGy-irradiated vitamin E/UHMWPE which was 17.0 minutes (15.0–17.1 minutes) (p = 0.040). After squalene immersion at 120° C, the incipient oxidation temperature of 100 and 150 kGy irradiated ls EGCG/UHMWPE was 234° C (227–240° C) and 227° C (225–229° C), which was higher than vitamin E-stabilized counterparts with value of 217° C (214–229° C; p = 0.095) and 216° C (207–218° C; p = 0.040), respectively. The electron spin resonance signal of 150 kGy irradiated ls EGCG/UHMWPE was qualitatively weaker than that of 150 kGy irradiated vitamin E/UHMWPE. Conclusions ls EGCG-stabilized UHMWPE demonstrated higher oxidation resistance than vitamin E-stabilized UHMWPE after squalene immersion, likely because ls EGCG donates more protons to eliminate macroradicals than vitamin E. Clinical Relevance Our in vitro findings provide support that ls EGCG may be effective in protecting against oxidation that may be associated with synovial fluid-associated oxidation of highly crosslinked UHMWPE joint replacement components.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF SEPARATION SCIENCE
·
2019
·Vol. 42
·期 22
·3451-3458
·
IF 2.516
Lili Lian,Xinhao Jiang,Jinyi Lv,Fengkun Bai,Bo Zhu,Dawei Lou
Glucose-derived carbon-decorated magnetic microspheres were synthesized by an easy hydrothermal carbonization method and used as a high-efficiency adsorbent to extract bisphenols in water and tea drinks. The as-prepared carbon-decorated magnetic microspheres had a well-defined core–shell structure with a shell thickness of about 5 nm. The microspheres possessed high saturation magnetization at 60.8 emu/g and excellent chemical stability in aqueous solution. The experimental parameters affecting the extraction efficiency, including extraction time, pH, adsorbent dosage, desorption solvents, desorption time, and solution volume were evaluated. Electrostatic and π–π interactions were the major driving forces during extraction. Overall, a new magnetic solid-phase extraction method of determining bisphenols was developed on the basis of as-prepared magnetic microspheres. The method had a wide linear range, low limits of detection (0.03–0.10 µg/L), and high recoveries (85.4–104.6%).
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
·
2019
·
IF 6.395
Ze Lin,Xiulan Weng,Gary Owens,Zuliang Chen
Most environmental contaminants exist as a complex mixture of both metallic and organic pollutants and it is thus often a major challenge to remove both components simultaneously. In this paper, due to its low cost and environmentally friendliness, iron nanoparticles (Fe NPs) were successfully prepared using a one-step green synthesis for the simultaneous in-situ remediation of mixed contaminants. Specifically Fe NPs were used for the simultaneous removal of Pb(II) and rifampicin. The removal efficiency for Pb(II) and rifampicin were 100% and 91.6%, respectively. To better understand the mechanism of mixed contaminant removal by Fe NPs various characterization methods and the major conditions impacting removal efficiency were examined. It was concluded that (1) polyphenols and caffeine, both ubiquitous in green tea extracts, acted as both reducing and capping agents during the preparation of Fe NPs, reducing the agglomeration of Fe NPs and increasing their stability and reactivity; (2) the removal mechanism of contaminants involved Pb(II) being adsorbed onto the surface of Fe NPs due to the innate strong adsorption of metal ions onto iron oxides , while rifampicin and Pb(II) both interacted positively with the functional groups on the surface of Fe NPs. Overall, this study demonstrated that green synthesis Fe NPs had potential for use as inexpensive and efficient adsorbent for the simultaneous removal of both Pb(II) and rifampicin from wastewater.
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2019
·Vol. 24
·期 4
·657
·
IF 3.06
Zhuo Chen,Dan Zhang,Jia-Jia Guo,Wei Tao,Rui-Xue Gong,Ling Yao,Xing-Long Zhang,Wei-Guo Cao
Hawk tea is a rich and edible resource, traditionally used as a beverage in South China. This drink has many pharmacologic effects, such as acting as an antioxidant and reducing blood sugar and lipids. The objective of this work was to explore the active compound contents, bioactivities and their monthly changes, and optimize the harvest time. In the present study, Hawk tea from each month in 2017 was collected and extracted with 70% (v/v) ethanol. The contents of the total flavonoids and total phenols were determined using the colorimetric method. We determined the contents of seven characteristic active substances—hyperin, isoquercitrin, trifolin, quercitrin, astragalin, quercetin, and kaempferol—using high-performance liquid chromatography. The crude extract was tested for its antioxidant and inhibitory properties on enzymes involved in metabolic syndrome. Specifically, 2,2-diphenyl-1-picrylhydrazyl, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid), ferric-reducing power assay, and the inhibition capacity test on α-glucosidase and lipase were conducted to determine the antioxidant effect in vitro, as well as the reduction of blood sugar and lipids. Monthly variations in activities and components were determined by numeric analysis and comparison. Correlation analysis revealed that antioxidant effects are significantly correlated with the total flavonoids. The hierarchical cluster analysis of bioactivities and their contents indicates that October and November are the best harvesting months, which differs with the habitual collection of Hawk tea.Keywords:Hawk tea;active components;antioxidant;α-glucosidase and lipase;monthly variation
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2018
·
IF 3.909
Ping Shao,Haoya Zhang,Ben Niu,Weiping Jin
In this research, Pickering emulsion stabilized by taro starch nanoparticles was successfully prepared, and the potential application of encapsulating tea polyphenols was investigated. The nanoparticle size (about 460 nm) and contact angle (81.5°) of taro starch indicate that it is suitable for adsorbing on the oil-water interface and forming a dense interfacial layer. Emulsion stability at different particle concentrations, oil-water ratios, and sodium chloride concentrations has been systematically studied. By considering the particle size, zeta potential , and stability index of Pickering emulsion, it is considered that the emulsion has the best stability when the particle concentration is 7% and the oil fraction is 0.5. Low concentration of salt ions (0.04 mM NaCl) will cause a slight flocculation to improve the stability, but adding high concentration of salt will make emulsion break. In addition, we found that this Pickering emulsion could encapsulate the tea polyphenols greatly with a retention rate of up to 67%. The findings may have great significance for the design and fabrication of native starch particle stabilized emulsion.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF FOOD SCIENCE
·
2018
·Vol. 83
·期 11
·2718-2732
·
IF 2.018
Huanhuan Li,Liyong Luo,Mengjun Ma,Liang Zeng
Jasmine scented black tea is widely popular in China and the scenting process is the most crucial issue affecting its aroma quality. This study aimed to analyze the influence of different processes on aroma quality and the specific contribution of volatiles to aroma quality. To achieve it, the headspace solid-phase microextraction method combined with gas-chromatography mass-spectrometry was used to identify and quantify the volatile compounds, and further collected the characteristics according to odor activity values or contents. The quantitative descriptive analysis (QDA) and traditional sensory analysis (TSA) were used to evaluate its aroma quality and the correlation analysis between QDA and characteristic aroma compounds was carry out to analyze the specific contribution of characteristics to sensory quality. The GC/MS results showed that 130 aroma components and 20 characteristics were identified in 6 tea samples and more new volatile components appeared and less original volatile components disappeared in traditional scenting process (TSP) compared with continuous scenting process (CSP). The QDA and TSA results showed that TSP samples had better “overall” and “jasmine” than CSP samples. The correlation analysis between QDA and characteristics showed that nerolidol and methylbenzoate were related to “overall,” linalool and methyl anthranilate to “jasmine,” and decanal and benzeneacetaldehyde to “sweet floral,” “roasted,” and “fermented.” This study suggested that TSP is a favorable scenting process for black tea, and QDA is an objective and digital sensory evaluation method for jasmine scented black tea. Practical Application Compare the effect of scenting technology on the aroma quality of jasmine scented black tea based on sensory analysis and chemical analysis, and suggested a favorable scenting process for processing jasmine scented black tea with better qualities. Explore the correlation between aroma composition and specific aroma properties to provide some useful information about guiding the scenting process to acquire a product with target aroma qualities. And the application of QDA for evaluation of jasmine scented black tea was better for consumers to understand the quality attributes of product.
✓ 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）