Materials
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2020
·Vol. 13
·期 17
·3857
·
IF 3.057
Liao Pan,Meiying Zhang,Lixin Lu,Bingxian Ou,Xi Chen
Antioxidant packaging is an effective method to protect oxygen-sensitive food from oxidation. In order to concurrently obtain a storage stability and excellent oxygen scavenging of antioxidant film for the high moisture food, a moisture activating oxygen scavenging film was prepared by using tea polyphenols as the oxygen scavenger. The moisture activating function was achieved by introducing the β-cyclodextrin embedding technology, and the tea polyphenols–β-cyclodextrin inclusion complex was co-extruded with low-density polyethylene (LDPE) to improve the storage stability. The results indicate that the tea polyphenols is well embedded by β-cyclodextrin according to the Fourier transform infrared spectra (FT-IR), and a relatively homogeneous dispersion of oxygen scavenger is observed while the oxygen scavenger content is less than 5%. The oxygen scavenging increases with the increase of oxygen scavenger from 1% to 5%, and a maximal oxygen absorption of 0.0150 mol/m2is exhibited at oxygen scavenger content value of 5%. Then, the oxygen scavenging significantly decrease under the oxygen scavenger content of 7% and 10%. Moreover, the oxygen scavenging amount sharply increase after steeping in water or storage in extremely high humidity of RH 84% while the oxygen scavenging is restrained under RH 32–75%, indicating that the moisture activating oxygen scavenging is functioning. The oxygen scavenging is obvious restrained under low temperature of 4 °C while the oxygen scavenging is activated at 23 °C and 50 °C with similar oxygen scavenging amount. Besides, both of the tensile and heat-sealing strength deteriorative with the increase of oxygen scavenger content, while they are acceptable at oxygen scavenger content of 5%. Finally, the prepared oxygen scavenging film was used for packaging orange juice and received a good antioxidant effect. Thus, the acquired moisture activating oxygen scavenging film has a good stability under regular storage condition, and shows a potentially application for oxygen-sensitive food with high moisture content.Keywords:moisture activating;oxygen scavenging film;tea polyphenols;β-cyclodextrin;low-density polyethylene (LDPE)
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JOURNAL OF FOOD PROCESS ENGINEERING
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2020
·Vol. 43
·期 7
·e13419
·
IF 1.703
Qingyi Wei,Ting Liu,Hongbin Pu,Da-Wen Sun
Tea polyphenols (TPs) are a major functional ingredient in tea, but current traditional detection methods for TPs are generally time-consuming and involve a lot of organic chemicals. In this study, carbon dots (CDs) with a high quantum yield of 73.66% was prepared using a rapid, safe, and economical way. The synthesized CDs had an average particle size of 5 nm in diameter and showed a strong emission peak at 445 nm when the excitation wavelength was 350 nm. Additionally, a fluorescent CDs/Cu 2+ probe was employed for detection of TPs. This fluorescent sensing approach allowed for detecting TPs in the range between 1 and 30 μg/mL with a low detection limit of 0.31 μg/mL. Besides, satisfactory recoveries of 101.11–106.97% in spiked real tea samples were obtained by this present probe. The outcomes confirmed the applicability of the fluorescent CDs/Cu 2+ probe for TPs measurements in spiked real samples. Moreover, as compared with the standard Folin–Ciocalteu method, the probe was facile and time-saving for the detection of TPs. Therefore, it is hoped that this effective way could also be employed to quantify phenolic compounds from other herbal plants in future studies. Practical Applications In this paper, low toxicity, low cost, simple synthetic, and water solubility of carbon dots (CDs) coupled with Cu 2+ was applied as a fluorescent probe to detect TPs. Compared with the traditional method, good applicability was shown with the proposed method for TPs measurements in real tea samples, indicating great potential for monitoring the content of TPs in tea. In the future, it could provide a sensitive and effective way of detecting phenolic compounds from other herbal plants for the industry.
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Environmental Progress & Sustainable Energy
·
2021
·Vol. 40
·期 6
·e13706
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IF 2.431
Shuang Liu,Shuaizhong Zhang,Minghao Fan,Yongkai Yuan,Xun Sun,Dongfeng Wang,Ying Xu
Nanoscale zero-valent iron (nZVI) loaded on tea residue biochar activated with phosphoric acid composites was synthesized. This adsorbent can efficiently adsorb multiple heavy metal ions such as Pb (II), Cr (III), Cu (II), and Ni (II) simultaneously. The adsorption process was found to follow the pseudo-second-order kinetic model. Equilibrium adsorption capacities reached 288.18, 162.34, 242.72, and 267.22 mg·g −1 for Pb(II), Cr(III), Cu(II), and Ni(II), respectively. The common interfering ions exhibited lower influence on its adsorption capacity. The adsorption mechanism includes reduction, ion exchange, surface complexation and precipitation. Furthermore, the waste adsorbent was converted into a catalyst in situ, which could catalyze the degradation of Congo red by establishing an electron transfer pathway. This research provides a new concept for the sustainable utilization of industrial tea residues and the harmless treatment of waste nZVI composite adsorbents.
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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.
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JOURNAL OF SEPARATION SCIENCE
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2019
·Vol. 42
·期 22
·3451-3458
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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%).
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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
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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.
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FOOD CHEMISTRY
·
2019
·
IF 5.399
Xi Chen,Mengshi Lin,Lin Sun,Taotao Xu,Keqiang Lai,Meizhen Huang,Hetong Lin
The contamination of pesticide residues in Oolong tea has raised much concern in recent years. The objective of this study was to synthesize gold nanoparticles (AuNPs) and develop surface-enhanced Raman spectroscopy (SERS) methods for detection and quantification of pesticides in Oolong tea. Facile synthesis of spherical and monodispersed AuNPs with an average diameter of 15 nm was achieved, which induced strong electromagnetic fields in SERS analysis. AuNP substrates were employed for rapid detection and quantification of carbendazim in Tieguanyin Oolong tea. Partial least squares (PLS) analysis and leave-one-out cross validation were utilized in spectral data analysis. The PLS results for Oolong tea samples were obtained: R value = 0.964; the detection limit = 100 μg/kg. These results demonstrate that SERS coupled with gold nanoparticle substrate is a simple, rapid, and sensitive analytical tool for measurement and quantification of carbendazim residues in Oolong tea.
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JOURNAL OF FOOD BIOCHEMISTRY
·
2019
·Vol. 44
·期 1
·e13096
·
IF 1.358
Tingfang Gao,Yuhong Shi,Ying Xue,Fen Yan,Da Huang,Yuanzi Wu,Zuquan Weng
In this study, tea polyphenols (TPs) was first extracted from tea waste by superheated steam (SS) pretreated ultrasonic-assisted hydrothermal extraction (UAH). The optimized strategy presented extracts with the extraction yield up to 21.19% with a significantly higher antioxidant ability, compared with the one without SS pretreatment. Further investigation proved that the SS suppressed the polyphenol oxidase activity of the TPs extract. The ability to scavenge the free radicals were compared in mouse liver mitochondria. Mitochondrial swelling, mitochondrial membrane potential (MMP), cardiolipin peroxidation, and respiratory chain complex (RCC) I–V activities were also evaluated as the index of the mitochondrial oxidative damage. The study supports evidence that the TPs extract exhibited significant protection against oxidative damage on mitochondrial. Furthermore, the effect of TPs on antioxidant ability in zebrafish embryo was evaluated. After TPs pretreatment for 1 day, zebrafish embryos showed a significantly higher survival rate as well as heart rate when facing the oxidative stress. Practical applications Polyphenols from tea leaves have been viewed as an antioxidant additive in food, mainly due to the ability of scavenging free radicals and reactive oxygen species. The results of this study suggest that the SS pretreatment could be used as an efficient method to extract TPs from the tea waste for the prevention of oxidative damage in the mouse liver mitochondria and zebrafish embryos.
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MICROCHEMICAL JOURNAL
·
2019
·
IF 3.206
Li Gao,Longhui Liu,Yaming Sun,Wenjie Zhao,Lijun He
A novel azamacrocycle-based adsorbent for solid-phase extraction was synthesized by coupling a 26-membered aromatic-aliphatic-mixed azamacrocycle to 3-chloropropyltrimethoxylsilane-modified silica. The obtained material was characterized by elemental analysis and fourier transform-infrared spectroscopy. The adsorbent showed excellent performance for extracting organophosphorus pesticides (fenitrothion, parathion, fenthion and phoxim), which may be due to multiple interactions between the adsorbent and organophosphorus pesticides, including π–π, hydrophobic, dipole-dipole, charge-transfer, hydrogen-bonding and inclusion interactions. The main parameters that affected the extraction efficiency were investigated, including the amount of adsorbent, the volume and flow rate of the sample solution, the elution solvent and the ionic strength. This azamacrocycle-based extraction technique was further combined with high-performance liquid chromatography to measure trace organophosphorus pesticides in tea drinks. The method showed good linearity (5–500 ng/mL), low limit of detection (0.10 ng/mL), and high recoveries from spiked samples (90.4%–113.5%) were obtained with low relative standard deviation (0.6%–8.9%, n = 3). The azamacrocycle-based adsorbent showed good extraction performance and offered a promising application in the extraction of organophosphorus pesticides from complicated tea drinks.
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FOOD RESEARCH INTERNATIONAL
·
2019
·
IF 3.579
Si Chen,Huihui Liu,Xiaoman Zhao,Xinlei Li,Wenna Shan,Xiaxia Wang,Shanshan Wang,Wenquan Yu,Zhenbiao Yang,Xiaomin Yu
Oolong tea is a partially fermented tea with distinct tastes and aromas. However, the dynamic biochemical changes during oolong tea processing are not well understood. In this study, we performed metabolomics-based profiling of non-volatile and volatile constituents of oolong tea during its entire processing procedures by UPLC-QTOF MS and GC-TOF MS. A step-wise change of tea metabolome was observed, where catechins and oxidized products, flavonol glycosides and amino acids were identified as key discriminate metabolites. The ZuoQing process comprising alternating YaoQing and TanQing steps was deemed most critical for key metabolic transformation. Extensive YaoQing facilitated the oxidative polymerizations of catechins into theaflavins and proanthocyanidins, lowering the astringency in raw tea. Two direct terpene precursors farnesyl pyrophosphate and geranyl pyrophosphate accumulated to high levels during ZuoQing, which provided more substrates for the synthesis of downstream volatile terpenes. Moreover, both YaoQing and prolonged TanQing facilitated the formation of terpenes as well as fatty acid and benzenoid-derived volatiles, which contributed to the fruity and floral fragrances in oolong tea. The fixation step not only converted amino acids into aromatic compounds, but also lowered the amounts of flavonol glycosides, potentially improving the flavor quality of the final tea product. This study provides a comprehensive profile of flavor-related metabolic changes during oolong tea processing and will contribute to better quality control and flavor improvement of oolong tea.
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Food & Function
·
2018
·Vol. 9
·期 9
·4858-4864
·
IF 3.289
Bo Chen,Jie Zhou,Qilu Meng,Yang Zhang,Shihua Zhang,Liang Zhang
Tea polyphenols (TP) have many health benefits, but most are metabolized into low molecular-weight phenolic acids after oral administration. In the present study, the absorption, metabolism, and excretion of catechins in rats fed a normal chow diet and in obese rats fed a high-fat and high-sugar (HFHS) diet were compared. After a ten-day oral administration of TP (500 mg per kg bw), the plasma levels of (−)-epigallocatechin gallate (EGCG) and (−)-gallocatechin gallate (GCG) in obese rats were significantly lower than those in the normal group. In obese rats, the fecal levels of EGCG, (−)-epicatechin gallate (ECG) and GCG were significantly enhanced. Ten phenolic metabolites of TP were quantitatively analyzed, and the results showed that 4-hydroxyphenylacetic acid was the primary metabolite in feces and plasma. The plasma and fecal concentrations of 4-hydroxyphenylacetic acid in the obese group were significantly lower than those in normal rats, but the levels of 4-hydroxyphenylpropionic acid in plasma and feces were increased. The content of other phenolic acids was also dramatically changed. These results suggested that a HFHS diet might influence the excretion of tea catechins, leading to insufficient metabolism of catechins by the gut microflora.
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