Foods

2024

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11 pages, 3495 KiB

Open AccessArticle

Tea’s Characteristic Components Eliminate Acrylamide in the Maillard Model System

by Zhihao Ye, Haojie Xu, Yingying Xie, Ziqi Peng, Hongfang Li, Ruyan Hou, Huimei Cai, Wei Song, Chuanyi Peng and Daxiang Li

Foods 2024, 13(17), 2836; https://doi.org/10.3390/foods13172836 - 6 Sep 2024

Viewed by 749

Abstract

This study investigated the effects of various characteristic components of tea—theaflavins, catechins, thearubigins, theasinensins, theanine, catechin (C), catechin gallate (CG), epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin (GC), and gallocatechin gallate (GCG)—on acrylamide formation. The results revealed that most [...] Read more.

This study investigated the effects of various characteristic components of tea—theaflavins, catechins, thearubigins, theasinensins, theanine, catechin (C), catechin gallate (CG), epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin (GC), and gallocatechin gallate (GCG)—on acrylamide formation. The results revealed that most of tea’s characteristic components could significantly eliminate acrylamide, ranked from highest to lowest as follows: GC (55.73%) > EC (46.31%) > theaflavins (44.91%) > CG (40.73%) > thearubigins (37.36%) > ECG (37.03%) > EGCG (27.37%) > theabrownine (22.54%) > GCG (16.21%) > catechins (10.14%) > C (7.48%). Synergistic elimination effects were observed with thearubigins + EC + GC + CG, thearubigins + EC + CG, thearubigins + EC + GC, theaflavins + GC + CG, and thearubigins + theaflavins, with the reduction rates being 73.99%, 72.67%, 67.62%, 71.03%, and 65.74%, respectively. Tea’s components reduced the numbers of persistent free radicals to prevent acrylamide formation in the model system. The results provide a theoretical basis for the development of low-acrylamide foods and the application of tea resources in the food industry. Full article

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13 pages, 2392 KiB

Open AccessArticle

¹H NMR Spectroscopy Combined with Machine-Learning Algorithm for Origin Recognition of Chinese Famous Green Tea Longjing Tea

by Zhiwei Hou, Yugu Jin, Zhe Gu, Ran Zhang, Zhucheng Su and Sitong Liu

Foods 2024, 13(17), 2702; https://doi.org/10.3390/foods13172702 - 27 Aug 2024

Viewed by 555

Abstract

Premium green tea is a high-value agricultural product significantly influenced by its geographical origin, making it susceptible to food fraud. This study utilized nuclear magnetic resonance (NMR) spectroscopy to perform chemical fingerprint analysis on 78 Longjing tea (LJT) samples from both protected designation [...] Read more.

Premium green tea is a high-value agricultural product significantly influenced by its geographical origin, making it susceptible to food fraud. This study utilized nuclear magnetic resonance (NMR) spectroscopy to perform chemical fingerprint analysis on 78 Longjing tea (LJT) samples from both protected designation of origin (PDO) regions (Zhejiang) and non-PDO regions (Sichuan, Guangxi, and Guizhou) in China. Unsupervised algorithms and heatmaps were employed for the visual analysis of the data from PDO and non-PDO teas while exploring the feasibility of linear and nonlinear machine-learning algorithms in discriminating the origin of LJT. The findings revealed that the nonlinear model random forest (92.2%), exhibited superior performance compared to the linear model linear discriminant analysis (85.6%). The random forest model identified 15 key marker metabolites for the geographical origin of LJT, such as kaempferol glycoside, glutamine, and ECG. The results support the conclusion that the integration of NMR with machine-learning classification serves as an effective tool for the quality assessment and origin identification of LJT. Full article

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15 pages, 8816 KiB

Open AccessArticle

The Potential Mechanisms of Catechins in Tea for Anti-Hypertension: An Integration of Network Pharmacology, Molecular Docking, and Molecular Dynamics Simulation

by Yanming Tuo, Xiaofeng Lu, Fang Tao, Marat Tukhvatshin, Fumin Xiang, Xi Wang, Yutao Shi, Jinke Lin and Yunfei Hu

Foods 2024, 13(17), 2685; https://doi.org/10.3390/foods13172685 - 26 Aug 2024

Viewed by 1168

Abstract

Catechins, a class of polyphenolic compounds found in tea, have attracted significant attention due to their numerous health benefits, particularly for the treatment and protection of hypertension. However, the potential targets and mechanisms of action of catechins in combating hypertension remain unclear. This [...] Read more.

Catechins, a class of polyphenolic compounds found in tea, have attracted significant attention due to their numerous health benefits, particularly for the treatment and protection of hypertension. However, the potential targets and mechanisms of action of catechins in combating hypertension remain unclear. This study systematically investigates the anti-hypertensive mechanisms of tea catechins using network pharmacology, molecular docking, and molecular dynamics simulation techniques. The results indicate that 23 potential anti-hypertensive targets for eight catechin components were predicted through public databases. The analysis of protein–protein interaction (PPI) identified three key targets (MMP9, BCL2, and HIF1A). KEGG pathway and GO enrichment analyses revealed that these key targets play significant roles in regulating vascular smooth muscle contraction, promoting angiogenesis, and mediating vascular endothelial growth factor receptor signaling. The molecular docking results demonstrate that the key targets (MMP9, BCL2, and HIF1A) effectively bind with catechin components (CG, GCG, ECG, and EGCG) through hydrogen bonds and hydrophobic interactions. Molecular dynamics simulations further confirmed the stability of the binding between catechins and the targets. This study systematically elucidates the potential mechanisms by which tea catechins treat anti-hypertension and provides a theoretical basis for the development and application of tea catechins as functional additives for the prevention of hypertension. Full article

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12 pages, 1912 KiB

Open AccessArticle

Functional Tea Extract Inhibits Cell Growth, Induces Apoptosis, and Causes G0/G1 Arrest in Human Hepatocellular Carcinoma Cell Line Possibly through Reduction in Telomerase Activity

by Yuan Chen, Changsong Chen, Jiaxing Xiang, Ruizhen Gao, Guojun Wang and Wenquan Yu

Foods 2024, 13(12), 1867; https://doi.org/10.3390/foods13121867 - 14 Jun 2024

Cited by 2 | Viewed by 669

Abstract

The functional tea CFT-1 has been introduced into China as a nutraceutical beverage according to the “Healthy China” national project. The effects on human hepatocellular carcinoma (HCC) cells remain unclear and were investigated with the functional tea extract (purity > 98%). The morphological [...] Read more.

The functional tea CFT-1 has been introduced into China as a nutraceutical beverage according to the “Healthy China” national project. The effects on human hepatocellular carcinoma (HCC) cells remain unclear and were investigated with the functional tea extract (purity > 98%). The morphological changes in the cells were observed with microscopes. Cell proliferation, migration, cycle distribution, and apoptotic effects were assessed by MTT, Transwell assays, and flow cytometry, respectively, while telomerase inhibition was evaluated with telomerase PCR ELISA assay kits. The CFT-1 treatment resulted in cell shrinkage, nuclear pyknosis, and chromatin condensation. CFT-1 suppressed the growth of Hep3B cells with IC50 of 143 μg/mL by inducing apoptosis and G0/G1 arrest in Hep3B cells. As for the molecular mechanism, CFT-1 treatment can effectively reduce the telomerase activity. The functional tea extract inhibits cell growth in human HCC by inducing apoptosis and G0/G1 arrest, possibly through a reduction in telomerase activity. These results indicate that CFT-1 extract exhibited in vitro anticancer activities and provided insights into the future development and utilization of CFT-1 as functional foods to inhibit the proliferation of HCC cells. Full article

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16 pages, 3202 KiB

Open AccessArticle

GC–MS Combined with Fast GC E-Nose for the Analysis of Volatile Components of Chamomile (Matricaria chamomilla L.)

by Jiayu Lu, Zheng Jiang, Jingjie Dang, Dishuai Li, Daixin Yu, Cheng Qu and Qinan Wu

Foods 2024, 13(12), 1865; https://doi.org/10.3390/foods13121865 - 13 Jun 2024

Cited by 1 | Viewed by 925

Abstract

Chamomile has become one of the world’s most popular herbal teas due to its unique properties. Chamomile is widely used in dietary supplements, cosmetics, and herbal products. This study aimed to investigate the volatile aromatic components in chamomile. Two analytical techniques, gas chromatography–mass [...] Read more.

Chamomile has become one of the world’s most popular herbal teas due to its unique properties. Chamomile is widely used in dietary supplements, cosmetics, and herbal products. This study aimed to investigate the volatile aromatic components in chamomile. Two analytical techniques, gas chromatography–mass spectrometry (GC-MS) and an ultra-fast gas chromatography electronic nose, were employed to examine samples from Xinjiang (XJ), Shandong (SD), and Hebei (HB) in China, and imported samples from Germany (GER). The results revealed that all chamomile samples contained specific sesquiterpene compounds, including α-bisabolol, bisabolol oxide, bisabolone oxide, and chamazulene. Additionally, forty potential aroma components were identified by the electronic nose. The primary odor components of chamomile were characterized by fruity and spicy notes. The primary differences in the components of chamomile oil were identified as (E)-β-farnesene, chamazulene, α-bisabolol oxide B, spathulenol and α-bisabolone oxide A. Significant differences in aroma compounds included geosmin, butanoic acid, 2-butene, norfuraneol, γ-terpinene. This study demonstrates that GC–MS and the ultra-fast gas chromatography electronic nose can preliminarily distinguish chamomile from different areas, providing a method and guidance for the selection of origin and sensory evaluation of chamomile. The current study is limited by the sample size and it provides preliminary conclusions. Future studies with a larger sample size are warranted to further improve these findings. Full article

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17 pages, 2865 KiB

Open AccessArticle

Distinct Changes in Metabolic Profile and Sensory Quality with Different Varieties of Chrysanthemum (Juhua) Tea Measured by LC-MS-Based Untargeted Metabolomics and Electronic Tongue

by Xing Tian, Haodong Wang, Liang Chen, Hanwen Yuan, Caiyun Peng and Wei Wang

Foods 2024, 13(7), 1080; https://doi.org/10.3390/foods13071080 - 1 Apr 2024

Cited by 1 | Viewed by 1370

Abstract

Chrysanthemum tea, a typical health tea with the same origin as medicine and food, is famous for its unique health benefits and flavor. The taste and sensory quality of chrysanthemum (Juhua) tea are mainly determined by secondary metabolites. Therefore, the present research adopted [...] Read more.

Chrysanthemum tea, a typical health tea with the same origin as medicine and food, is famous for its unique health benefits and flavor. The taste and sensory quality of chrysanthemum (Juhua) tea are mainly determined by secondary metabolites. Therefore, the present research adopted untargeted metabolomics combined with an electronic tongue system to analyze the correlation between the metabolite profiles and taste characteristics of different varieties of chrysanthemum tea. The results of sensory evaluation showed that there were significant differences in the sensory qualities of five different varieties of chrysanthemum tea, especially bitterness and astringency. The results of principal component analysis (PCA) indicated that there were significant metabolic differences among the five chrysanthemum teas. A total of 1775 metabolites were identified by using untargeted metabolomics based on UPLC-Q-TOF/MS analysis. According to the variable importance in projection (VIP) values of the orthogonal projections to latent structures discriminant analysis (OPLS-DA), 143 VIP metabolites were found to be responsible for metabolic changes between Huangju and Jinsi Huangju tea; among them, 13 metabolites were identified as the key metabolites of the differences in sensory quality between them. Kaempferol, luteolin, genistein, and some quinic acid derivatives were correlated with the “astringency” attributes. In contrast, l-(-)-3 phenyllactic acid and L-malic acid were found to be responsible for the “bitterness” and “umami” attributes in chrysanthemum tea. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis showed that the flavonoid and flavonol biosynthesis pathways had important effects on the sensory quality of chrysanthemum tea. These findings provide the theoretical basis for understanding the characteristic metabolites that contribute to the distinctive sensory qualities of chrysanthemum tea. Full article

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14 pages, 1414 KiB

Open AccessReview

Recent Advances Regarding Polyphenol Oxidase in Camellia sinensis: Extraction, Purification, Characterization, and Application

by Chun Zou, Xin Zhang, Yongquan Xu and Junfeng Yin

Foods 2024, 13(4), 545; https://doi.org/10.3390/foods13040545 - 9 Feb 2024

Cited by 2 | Viewed by 1906

Abstract

Polyphenol oxidase (PPO) is an important metalloenzyme in the tea plant (Camellia sinensis). However, there has recently been a lack of comprehensive reviews on Camellia sinensis PPO. In this study, the methods for extracting PPO from Camellia sinensis, including acetone [...] Read more.

Polyphenol oxidase (PPO) is an important metalloenzyme in the tea plant (Camellia sinensis). However, there has recently been a lack of comprehensive reviews on Camellia sinensis PPO. In this study, the methods for extracting PPO from Camellia sinensis, including acetone extraction, buffer extraction, and surfactant extraction, are compared in detail. The main purification methods for Camellia sinensis PPO, such as ammonium sulfate precipitation, three-phase partitioning, dialysis, ultrafiltration, ion exchange chromatography, gel filtration chromatography, and affinity chromatography, are summarized. PPOs from different sources of tea plants are characterized and systematically compared in terms of optimal pH, optimal temperature, molecular weight, substrate specificity, and activators and inhibitors. In addition, the applications of PPO in tea processing and the in vitro synthesis of theaflavins are outlined. In this review, detailed research regarding the extraction, purification, properties, and application of Camellia sinensis PPO is summarized to provide a reference for further research on PPO. Full article

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2023

Jump to: 2024

27 pages, 925 KiB

Open AccessReview

Research Review on Quality Detection of Fresh Tea Leaves Based on Spectral Technology

by Ting Tang, Qing Luo, Liu Yang, Changlun Gao, Caijin Ling and Weibin Wu

Foods 2024, 13(1), 25; https://doi.org/10.3390/foods13010025 - 20 Dec 2023

Cited by 3 | Viewed by 2271

Abstract

As the raw material for tea making, the quality of tea leaves directly affects the quality of finished tea. The quality of fresh tea leaves is mainly assessed by manual judgment or physical and chemical testing of the content of internal components. Physical [...] Read more.

As the raw material for tea making, the quality of tea leaves directly affects the quality of finished tea. The quality of fresh tea leaves is mainly assessed by manual judgment or physical and chemical testing of the content of internal components. Physical and chemical methods are more mature, and the test results are more accurate and objective, but traditional chemical methods for measuring the biochemical indexes of tea leaves are time-consuming, labor-costly, complicated, and destructive. With the rapid development of imaging and spectroscopic technology, spectroscopic technology as an emerging technology has been widely used in rapid non-destructive testing of the quality and safety of agricultural products. Due to the existence of spectral information with a low signal-to-noise ratio, high information redundancy, and strong autocorrelation, scholars have conducted a series of studies on spectral data preprocessing. The correlation between spectral data and target data is improved by smoothing noise reduction, correction, extraction of feature bands, and so on, to construct a stable, highly accurate estimation or discrimination model with strong generalization ability. There have been more research papers published on spectroscopic techniques to detect the quality of tea fresh leaves. This study summarizes the principles, analytical methods, and applications of Hyperspectral imaging (HSI) in the nondestructive testing of the quality and safety of fresh tea leaves for the purpose of tracking the latest research advances at home and abroad. At the same time, the principles and applications of other spectroscopic techniques including Near-infrared spectroscopy (NIRS), Mid-infrared spectroscopy (MIRS), Raman spectroscopy (RS), and other spectroscopic techniques for non-destructive testing of quality and safety of fresh tea leaves are also briefly introduced. Finally, in terms of technical obstacles and practical applications, the challenges and development trends of spectral analysis technology in the nondestructive assessment of tea leaf quality are examined. Full article

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17 pages, 3856 KiB

Open AccessArticle

Huangqin Tea Total Flavonoids–Gut Microbiota Interactions: Based on Metabolome and Microbiome Analysis

by Yaping Zheng, Kailin Yang, Jie Shen, Xiangdong Chen, Chunnian He and Peigen Xiao

Foods 2023, 12(24), 4410; https://doi.org/10.3390/foods12244410 - 7 Dec 2023

Cited by 2 | Viewed by 1603

Abstract

Huangqin tea (HQT), a Non-Camellia Tea derived from the aerial parts of Scutellaria baicalensis, is widely used in the north of China. The intervention effects of HQT on intestinal inflammation and tumors have been found recently, but the active ingredient and [...] Read more.

Huangqin tea (HQT), a Non-Camellia Tea derived from the aerial parts of Scutellaria baicalensis, is widely used in the north of China. The intervention effects of HQT on intestinal inflammation and tumors have been found recently, but the active ingredient and mechanism of action remain unclear. This study aimed to investigate the interactions between the potential flavonoid active components and gut microbiota through culture experiments in vitro combined with HPLC-UV, UPLC-QTOF-MS, and 16S rDNA sequencing technology. The results showed that the HQT total flavonoids were mainly composed of isocarthamidin-7-O-β-D-glucuronide, carthamidin-7-O-β-D-glucuronide, scutellarin, and others, which interact closely with gut microbiota. After 48 h, the primary flavonoid glycosides transformed into corresponding aglycones with varying degrees of deglycosylation. The composition of the intestinal microbiota was changed significantly. The beneficial bacteria, such as Enterococcus and Parabacteroides, were promoted, while the harmful bacteria, such as Shigella, were inhibited. The functional prediction results have indicated notable regulatory effects exerted by total flavonoids and scutellarin on various pathways, including purine metabolism and aminoacyl-tRNA biosynthesis, among others, to play a role in the intervention of inflammation and tumor-related diseases. These findings provided valuable insights for further in-depth research and investigation of the active ingredients, metabolic processes, and mechanisms of HQT. Full article

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16 pages, 2320 KiB

Open AccessArticle

The Effects of Structure and Oxidative Polymerization on Antioxidant Activity of Catechins and Polymers

by Wei Wang, Ting Le, Wei-Wei Wang, Jun-Feng Yin and He-Yuan Jiang

Foods 2023, 12(23), 4207; https://doi.org/10.3390/foods12234207 - 22 Nov 2023

Cited by 1 | Viewed by 1298

Abstract

Polyphenols are key free radical scavengers in tea. This study screened the antioxidant active groups of catechins and dimers and analyzed the effects of the degree of oxidative polymerization and oxidative dimerization reaction on their antioxidant activities. ABTS^+· free radical scavenging activity, [...] Read more.

Polyphenols are key free radical scavengers in tea. This study screened the antioxidant active groups of catechins and dimers and analyzed the effects of the degree of oxidative polymerization and oxidative dimerization reaction on their antioxidant activities. ABTS^+· free radical scavenging activity, DPPH free radical scavenging activity, and total antioxidant capacity of catechins and polymers were systematically analyzed and compared in this study. Results manifested antioxidant activities of catechins were dominated by B-ring pyrogallol and 3-galloyl, but were not decided by geometrical isomerism. 3-galloyl had a stronger antioxidant activity than B-ring pyrogallol in catechins. The number, not the position, of the galloyl group was positively correlated with the antioxidant activities of theaflavins. Theasinensin A has more active groups than (−)-epigallocatechin gallate and theaflavin-3,3′-digallate, so it had a stronger antioxidant activity. Additionally, the higher the degree of oxidation polymerization, the weaker the antioxidant activities of the samples. The oxidative dimerization reaction hindered the antioxidant activities of the substrate–catechin mixture by reducing the number of active groups of the substrate and increasing the molecular structure size of the product. Overall, pyrogallol and galloyl groups were antioxidant active groups. The degree of oxidative polymerization and the oxidative dimerization reaction weakened the antioxidant activity. Full article

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2 pages, 160 KiB

Open AccessEditorial

Advances in Tea Chemistry

by Qing-Qing Cao, Ying Gao and Yong-Quan Xu

Foods 2023, 12(21), 3944; https://doi.org/10.3390/foods12213944 - 28 Oct 2023

Viewed by 1263

Abstract

The origins of tea, a traditional beverage in China, can be traced back to the Shennong period, about 2737 years before the birth of Christ [...] Full article

13 pages, 1473 KiB

Open AccessArticle

Quantitative Analysis of Bioactive Compounds in Commercial Teas: Profiling Catechin Alkaloids, Phenolic Acids, and Flavonols Using Targeted Statistical Approaches

by Yuan Chen, Lingling Lai, Youli You, Ruizhen Gao, Jiaxin Xiang, Guojun Wang and Wenquan Yu

Foods 2023, 12(16), 3098; https://doi.org/10.3390/foods12163098 - 17 Aug 2023

Cited by 6 | Viewed by 1516

Abstract

Tea, an extensively consumed and globally popular beverage, has diverse chemical compositions that ascertain its quality and categorization. In this investigation, we formulated an analytical and quantification approach employing reversed-phase ultra-high-performance liquid chromatography (UHPLC) methodology coupled with diode-array detection (DAD) to precisely quantify [...] Read more.

Tea, an extensively consumed and globally popular beverage, has diverse chemical compositions that ascertain its quality and categorization. In this investigation, we formulated an analytical and quantification approach employing reversed-phase ultra-high-performance liquid chromatography (UHPLC) methodology coupled with diode-array detection (DAD) to precisely quantify 20 principal constituents within 121 tea samples spanning 6 distinct variants. The constituents include alkaloids, catechins, flavonols, and phenolic acids. Our findings delineate that the variances in chemical constitution across dissimilar tea types predominantly hinge upon the intricacies of their processing protocols. Notably, green and yellow teas evinced elevated concentrations of total chemical moieties vis à vis other tea classifications. Remarkably divergent levels of alkaloids, catechins, flavonols, and phenolic acids were ascertained among the disparate tea classifications. By leveraging random forest analysis, we ascertained gallocatechin, epigallocatechin gallate, and epicatechin gallate as pivotal biomarkers for effective tea classification within the principal cadre of tea catechins. Our outcomes distinctly underscore substantial dissimilarities in the specific compounds inherent to varying tea categories, as ascertained via the devised and duly validated approach. The implications of this compositional elucidation serve as a pertinent benchmark for the comprehensive assessment and classification of tea specimens. Full article

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