JOURNAL OF FOOD PROCESS ENGINEERING
·
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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高影响因子
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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PubMed
高影响因子
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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PubMed
高影响因子
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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Foods
·
2023
·Vol. 12
·期 23
·4366
·
IF 5.2
Ying Li,Liya Niu,Chao Sun,Dongming Li,Zicong Zeng,Jianhui Xiao
Nowadays, medium chain triglycerides (MCT) with special health benefits have been increasingly applied for fortifying food products. Therefore, the present work aimed to investigate the effects of MCT on traditional tea polyphenols-fortified cooked rice (TP-FCR). It was visualized by DSC, CLSM, XRD, FT-IR, and Raman spectroscopy. The higher content of starch-MCT complexes with an increase in the relative crystallinity and the generation of short-range ordered structures contributed to a more ordered and compact molecular arrangement, which can hinder the action of digestive enzymes on starch. SEM demonstrated that MCT transformed the microstructure of TP-FCR into a denser and firmer character, making it an essential component hindering the accessibility of digestive enzymes to starch granules and slowing the release of tea polyphenols in TP-FCR to attenuate starch digestion. Consequently, the addition of MCT reduced the polyphenol-regulated starch digestibility from 74.28% in cooked white rice to 64.43% in TP-FCR, and further down to 50.82%. Besides, MCT also reduced the adhesiveness and improved the whiteness of TP-FCR. The findings suggested that MCT incorporation could be a potential strategy in cooked rice production to achieve high sensory quality and low glycemic cooked rice.Keywords:medium chain triglycerides;starch-lipid complexes;tea polyphenols-fortified cooked rice;digestion characteristics
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高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2023
·
IF 6.1
Yuqing Zhong,Yongling Lu,Lishuang Lv
Reactive carbonyl species (RCS) are generated during thermal food processing, and their accumulation in the body increases the risk of various chronic diseases. Herein, the RCS-scavenging ability of theanine, a unique nonproteinogenic amino acid, was evaluated in terms of the scavenging rate, reaction kinetics, and reaction pathway using LC–MS/MS. Three major products of theanine conjugated with acrolein (ACR) and glyoxal (GO) were prepared and identified using nuclear magnetic resonance. Thereafter, the simultaneous reactions of four types of RCS (namely, ACR, crotonaldehyde, methylglyoxal, and GO) with theanine were discussed in RCS–theanine and RCS–tea models. Under different reaction ratios, theanine could nonspecifically scavenge the four coexisting RCS by forming adducts with them. The amount of theanine–RCS adducts in green and black tea was more than that of catechin (epigallocatechin gallate, epigallocatechin, epicatechin gallate, and epicatechin)–RCS adducts despite the lower content of theanine than catechins. Thus, theanine, as a food additive and dietary supplement, could demonstrate new bioactivity as a promising RCS scavenger in food processing.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2023
·
IF 5.2
Datong Liu,Sijie Lei,Yang Hu,Zhanguo Li,Hailing Xi,Xiaoyan Lin
Currently, bare silica nanoparticles with low surface activity and weak stabilizing foam ability have restricted applicability in treating surface radioactive pollutants. To address potential issues with SiO 2 as a foam stabilizer , a highly efficient foam stabilizer was fabricated by compounding silica with hydroxylated graphene oxide (GO-OH), which was prepared by hydrothermal modification of graphene oxide (GO). Then, an environmentally friendly foam detergent with high stability and high decontamination efficiency was developed using the natural surfactant tea saponin (TAS) as a foaming agent and a composite of silica and GO-OH (GO-OH/SiO 2 ) as a foam stabilizer, which is named tea saponin foam detergent. For different types of surfactants, the structural and morphological characteristics of GO-OH, such as hydrophilic and surface oxygen groups, as well as the synergistic influence of GO-OH with SiO 2 on foamability, foam stability, and detergency of the foam detergent, were studied. As a consequence, the TAS foam detergent has good stability with a drain half-life of 68 min. By hydrothermal modification of GO, the contact angle of water on GO-OH in air dropped to 63.2°, which was lower than that (73.0°) on GO. Furthermore, the hydrophilicity of GO-OH increased, and more oxygen-containing groups on GO-OH enhanced its absorption and enrichment of the radionuclide uranium and improved the decontamination rate of the TAS foam detergent. Moreover, when GO-OH was combined with SiO 2 , the dispersion and stability of SiO 2 in the foam detergent improved, and the foam stability of the detergent subsequently further improved. Adding 2 wt% SiO 2 and 0.1 wt% GO-OH to the detergent enhanced the foam drainage half-life of the detergent from 40 min to 68 min and improved the stability of the detergent by 70%. In addition, the synergistic action of GO-OH/SiO 2 with TAS surfactant increased the liquid film thickness of the foam and the airflow resistance to support the weight-bearing capacity of the foam skeleton. As a result, it slowed the rate of foam disproportionation , reduced the bubble size, increased the bubble number, and finally improved the foam stability of the detergent. For simulated radioactive uranium pollutants on the surfaces of glass, stainless steel , and tiles, the foam detergent with the synergistic action of GO-OH/SiO 2 and TAS surfactant had decontamination rates of 91.7%, 91.16% and 91.76%, respectively, which were 14.96%, 15.67% and 19.39% higher than that of TAS foam detergent without GO-OH/SiO 2 . The synergistic enhancement of GO-OH and SiO 2 on foam stability and its adsorption and combination action with uranyl ions would be the main reasons to improve the detergency of the TAS foam detergent. Therefore, TAS foam detergent stabilized synergistically by GO-OH/SiO 2 with high stability and efficient decontamination will be widely applied in nuclear emergencies and decommissioning decontamination of nuclear facilities.
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高影响因子
ACS Applied Nano Materials
·
2023
·
IF 5.9
Nahar Jannatun,Yuqian Zhang,Ben Wu,Qingle Song,Guoli Cao,Wenhe Luo,Feng Yuan,Qi Li,Yanqiao Zeng,Guofang Zhang,Guocheng Wang,Yang Li
Epigallocatechin-3-gallate (EGCG), the most abundant tea polyphenol, possesses excellent anti-inflammation properties. Emerging studies proved its potent potential as an immune checkpoint (ICP) inhibitor for anticancer therapy. However, the low bioavailability of EGCG reduces its treatment efficiency. In this work EGCG-based nanomedicine EGCG–ZIF-8@PDA–PEG (EZP) was developed via the coordination between ZIF-8 MOF and EGCG, followed by polydopamine and PEG functionalization for efficient tumor-targeting EGCG delivery. Results demonstrated that the EGCG loading rate in EZP reached up to 85%. Both in vitro and in vivo studies proved that the EZP nanoparticles were capable of inhibiting the expression of ICP molecules and modulating the inflammatory tumor microenvironment, evidenced by the suppression of PD-L1 expression, the reduction of inflammatory cytokines, and the resultant decline in the number of immunosuppressive cells, for instance, myeloid-derived suppressor cells, tumor-associated macrophages, and regulatory T cells. These synergistic effects significantly improved the infiltration of dendritic cells and T cells in tumors, realizing an inspiring antitumor effect.
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高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
·
2023
·
IF 6
Jie-Qiong Wang,Zhuo-Shun Dai,Ying Gao,Fang Wang,Jian-Xin Chen,Zhi-Hui Feng,Jun-Feng Yin,Liang Zeng,Yong-Quan Xu
The stability of flavor in ready-to-drink tea beverages has been a pressing concern for the tea beverage industry. This study aimed to investigate the flavor quality changes in Dahongpao oolong tea beverages stored under different conditions (4 °C and 37 °C) using ultra-high-performance liquid chromatography coupled with ultra-high-performance liquid chromatography-quadrupole exactive-orbitrap mass spectrometry and headspace solid phase micro-extraction-gas chromatography-mass spectrometry. The results revealed that, compared to the samples stored at 4 °C, those stored at 37 °C exhibited noticeable color changes, transitioning from a mellower and sweet aftertaste to a riper and coarser flavor profile, with a decrease in roasted aroma. Utilizing orthogonal partial least square discriminant analysis, 37 key taste substances were identified, including gallic acid, catechin, 3- O - p -coumaroylquinic acid, epigallocatechin gallate, and ellagic acid, which experienced changes of 358.50%, 90.35%, 207.59%, −98.98%, and 866.10%, respectively (4 °C→37 °C). Moreover, through chemometric analysis and relative odor activity values＞1, β -damascone, linalool, and 2-ethyl-5-methyl pyrazine were identified as key contributors, with the carotenoid-derived pathway playing a more significant role. This study provides valuable insights for understanding and addressing flavor stability in tea beverages.
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JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2023
·
IF 4.3
Baosong Wang,Mingguang Yu,Yuan Tang,Ying Wang,Tianze Xia,Huanlu Song
Different methods for extraction and analysis of odor-active compounds in Dahongpao (DHP) Wuyi Rock Tea (WRT) were compared. The results showed that two-dimensional gas chromatography–olfactometry–mass spectrometry (GC×GC–O–MS) is a better method than GC–O–MS, stir bar sorptive extraction (SBSE) can extract more odor-active compounds. Aroma extraction dilution analysis (AEDA) and odor activity value (OAV) further indicated that 15 compounds were the most important odor-active compounds in DHP: phenethyl alcohol, ( E )- β -ionone, nonanal, linalool, hexanal, geraniol, benzaldehyde, α -ionone, methyl salicylate, 6-methyl-5-hepten-2-one, geranylacetone, benzyl alcohol, tea pyrrole and hexyl hexanoate. The roasting process affected the overall odor characteristics of DHP, and appropriate roasting would enhance the sensory quality of DHP. As the roasting temperature increases, the contribution of compounds such as tea pyrrole, 2-ethyl-6-methylpyrazine, and 2,6-dimethylpyrazine to the roasted and burnt odor of the samples gradually increase, and the concentration of typical floral compounds such as phenethyl alcohol, ( E )- β -ionone, α -ionone and linalool increase decidedly under light fire roasting, which was consistent with the sensory evaluation results. This study is helpful to further guide the production process of DHP.
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高影响因子
INTERNATIONAL JOURNAL OF FOOD PROPERTIES
·
2023
·
IF 2.9
Lixia Zan,Chao Wang
This study presents an ecologically conscious methodology for synthesizing tea polypeptides-selenium nanoparticles (TP-SeNPs) exhibiting antioxidant and antibacterial properties, utilizing tea polypeptides (TP). Proteins were extracted from tea leaves using an alkali extraction-acid precipitation method, and response surface methodology (RSM) was employed to optimize the preparation processes for both TP and TP-SeNPs. The TP extract was obtained with the highest TP content of 28.12% at a pH of 6, temperature of 50°C, duration of 3 h, and enzyme concentration of 4%. TP-SeNPs with a minimum particle size of 98 nm were biosynthesized by adding 3% TP at pH 4 and reaction temperature of 55°C for 6 h. The UV spectrum of TP-SeNPs showed an absorption peak at 285 nm. The EDS peak at 1.37 keV confirmed the presence of selenium in TP-SeNPs. Electron microscopy revealed a thin layer coating on the surface of TP-SeNPs. Infrared analysis showed changes in the C=O, NH, and C-N bonds. XRD analysis indicated the formation of a crystalline structure in TP-SeNPs. The absorbance ratio of the peptide selenium nanoparticle colloidal solution remained stable over 7 days at 25°C and 4°C. TP-SeNPs exhibited higher antioxidant activity than SeNPs at high concentrations. TP-SeNPs contain selenium, carbon, oxygen, and nitrogen, and TP plays a role in stabilizing and encapsulating TP-SeNPs. This may involve physical adsorption, covalent interactions, and other unknown interactions, preventing aggregation or degradation. The crystalline structure of TP-SeNPs improves their material properties and enhances their antioxidant and antibacterial abilities.
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高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
·
2023
·
IF 6
Xuchao Yin,Yuming Wei,Tiehan Li,Jixin Zhang,Li Zou,Qingqing Cui,Chengye Lu,Jingming Ning
Maillard reactions occurred during the roasting process of large-leaf yellow tea (LYT) were the main reason for the formation of their unique flavor. However, the contribution of different amino acids and soluble sugars to the formation of heterocyclic compounds in the Maillard reaction is still unclear. First, this study found that trimethylpyrazine, 2-ethyl-3,5-dimethylpyrazine, 3-ethyl-2,5-dimethylpyrazine and 2,5-diethylpyrazine, which had higher odor activity values (OAV), were significantly increased with the increase of roasting temperature. In contrast, only five amino acids ( l -theanine, glutamic acid, lysine, glutamine, histidine) and three monosaccharides ( d -glucose, d -fructose, and l -fucose) decreased significantly with increasing roasting temperature, which were significantly and positively correlated with each other. This indicates that these five amino acids and three monosaccharides were involved in the Maillard reaction during the roasting process. In addition, the model thermal reaction results showed that lysine contributed significantly to the formation of pyrazine especially with d -glucose to methylpyrazine, 2,5-dimethylpyrazine, trimethylpyrazine and 3-ethyl-2,5-dimethylpyrazine, while l -theanine contributed significantly to the formation of 1-ethylpyrrole-2-carbaldehyde. The d -glucose and d -fructose were the main contributors to the Maillard reaction among soluble sugars. This study lays the foundation for future studies on the relationship between volatile compounds and Maillard reactions.
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高影响因子
危险品化学品经营许可证（带存储）