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Enterobacter sakazakii is a food-borne bacterium that causes diseases as diverse as necrotizing enteritis, meningitis and infantile sepsis. Catechin is a kind of natural polyphenol products existing in tea and other natural plants, which has good antibacterial activity. In this study, laser confocal scanning microscopy and field emission scanning electron microscopy observations showed that the cell membrane of E. sakazakii was damaged after the action of catechin, and the cell surface adhered and pitted with holes. Under 1 MIC concentration, E. sakazakii membrane potential increased by 24.79%, intracellular reactive oxygen species increased by 4.72 times, intracellular ATP decreased by 4.93 times, and intracellular pH decreased by 45.63%. These results indicate that catechin can achieve antibacterial effect by disrupting cell membrane integrity and changing cell membrane permeability. This study lays a theoretical foundation for the application of catechin as a natural antibacterial agent. [ABSTRACT FROM AUTHOR]

[Objective] Through conducting a in-depth study on the variety diversity of Yunnan big-leaf tea, analyzing the diversity of their biochemical components with corresponding varieties and screening the specific varieties, the purpose of this paper was to provide theoretical guidance for the exploration, utilization, reproduction of those specific varieties. [Method] The biochemical components of autumn tea of 26 Yunnan big-leaf tea varieties were determined, and based on the results, principal component analysis and cluster analysis were carried out. [Result] The biochemical components of 26 varieties had rich diversity and variation, with an average coefficient of variation of 25.53%. Among the four conventional biochemical components, the largest coefficient of variation was amino acid, up to 14.13%. Among the catechin components, catechin had the largest coefficient of variation, reaching 63.51%. Multivariate principal component analysis showed that the first three principal components accounted for 77.179% of the diversity of biochemical components of 26 varieties, the variance accounted for by the first principal component was 50.165%, the contribution of phenol ammonia ratio was the largest; the variance accounted for by the second principal component was 16.894%, the contribution of epicatechin (EC) was the largest; the variance accounted for by the third principal component was 10.120%, and the contribution of epigallocatechin gallate (EGCG) was the largest. Based on the clustering of 12 biochemical components of 26 variety resources, three groups were formed. The first group mainly was Yunkang series variety resources, which were mainly characterized by high contents of water extract, tea polyphenols, phenol ammonia ratio, total catechin, catechin DL-C and epigallocatechin gallate (ECG), and low contents of amino acids and epigallocatechin (EGC) . The second group was Yunnan large leaf population resources, which were characterized by high contents of amino acids, caffeine and EC, and low contents of total catechin, EGCG and ECG, The third group was mainly artificial hybrid variety resources, which were characterized by high contents of EGC and EGCG, and low contents of water extract, tea polyphenols, caffeine, phenol ammonia ratio, catechin DL-C and EC. The contents of four conventional components of the three groups were relatively consistent, and there were differences in phenol ammonia ratio and catechin content. [Conclusion] 26 Yunnan big-leaf tea variety resources have rich genetic diversity, with 26 high tea polyphenol resources, 1 high caffeine resources and 15 high catechin resources were preliminarily screened. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of catechin on myocardial injury and anti-inflammatory effects in rats with coronary heart disease through PI3K-Akt-eNOS signaling pathway. Methods: Healthy adult SPF-grade SD male rats were injected with pituitrin intraperitoneally to establish coronary heart disease model. The expression of PI3K-Akt-eNOS signaling pathway was detected by Western blot. The expressions of inflammatory factors and oxidative stress were detected by ELISA. Myocardial injury in rats was observed and recorded. Results: Compared with blank group, myocardial ischemia and myocardial infarction area in model group, catechin low-dose group, catechin medium-dose group and catechin high-dose group were higher (P<0.05). The area of myocardial ischemia and myocardial infarction in catechin high-dose group was smaller than that in model group, catechin low-dose group and catechin medium-dose group (P<0.05). Compared with blank group, PI3K, p-Akt /Akt and P-ENOS /eNOS in model group, catechin low-dose group, catechin medium-dose group and catechin high-dose group were higher (P<0.05). PI3K, P-Akt /Akt and P-ENOS /eNOS in catechin high-dose group were higher than those in model group, catechin low-dose group and catechin medium-dose group (P<0.05); Compared with blank group, TNF-α, IL-1βand IL-18 in model group, catechin low-dose group, catechin medium-dose group and catechin high-dose group were higher (P<0.05). TNF-α, IL-1βand IL-18 in catechin high-dose group were lower than those in model group, catechin low-dose group and catechin medium-dose group (P<0.05). Compared with blank group, ROS, GSH-Px and MDA in model group, catechin low-dose group, catechin medium-dose group and catechin high-dose group were higher (P<0.05). TNF-α, IL-1β and IL-18 in catechin high-dose group were lower than those in model group, catechin low-dose group and catechin medium-dose group (P<0.05). Conclusions: Catechin can improve myocardial inflammation and oxidative stress in rats with coronary heart disease by targeting the PI3K-Akt-eNOS signaling pathway, and thus play a myocardial protective role. [ABSTRACT FROM AUTHOR]

[Objective] The investigation of quality statue of Sichuan green tea was performed and it would provide data support for the quality improvement of Sichuan green tea. [Method] In the study, 68 green tea samples from the main tea areas in Sichuan province were used as the survey objects, and the main biochemical components (water extract, tea polyphenols, soluble sugar, gallic acid, caffeine, catechin components, amino acid components) and its taste contribution were systematically analyzed. The taste difference between different grades of green tea was studied by the orthogonal partial least squares method (OPLS-DA). Combined with the results of the sensory evaluation, flavor wheel of taste was drawn. 【Result】 Analysis of biochemical components with Dot ( Dove-over-threshold) greater than I found that y-aminobu- tyric acid, caffeine, EGC, EGCG, GCG, and ECG were the main contributors to the bitterness of Sichuan green tea; EGC, EGCG, GCG, and ECG were the main contributors to the astringency; Glutamate was the main contributor to umami. Through the OPLS-DA model, the VIP values of 15 biochemical components such as gallic acid cysteine, total catechins, and soluble sugar were greater than 1, indicating that they had a greater impact on the classification of Sichuan green tea. Contribution, that was, these 15 components were the differential com- ponents related to the taste of Sichuan green tea. The flavor wheel showed that bitterness, astringency, freshness, sweetness, and sourness were the main characteristic flavors of Sichuan green tea. And grassy smell, burnt bitter, smoky, sour and stale were defective taste types. 【Conclusion] Based on the Dot value and OPLS-DA modeling analysis of taste characteristic components, combined with the flavor wheel, different grades of green tea can be distinguished, which provides new ideas and methods for building a technical standard system for taste quality of Sichuan green tea. [ABSTRACT FROM AUTHOR]

【Objective】 The differences of biochemical components of Pu-erh raw tea stored at different times and its antioxidant activity in aged mice were determined and compared. 【Method】 The contents of water extraction, tea polyphenols, catechins, amino acids, caffeine, flavonoids and soluble sugar of Pu-erh raw tea stored at different years (in 2014 and 2020) were determined. Moreover, the effects of Pu-erh raw tea stored at different times on body weight, water consumption, food intake, liver index, kidney index, spleen index, activities of glutamic-pyruvic transaminase (ALT), glutamic oxalacetic transaminase (AST) and superoxide dismutase (SOD), and contents of glutathione (GSH) and malondialdehyde (MDA) in serum and liver of aged mice were determined. 【Result】 The contents of water extraction (40.11%), amino acids (3.15%), caffeine (4.18%), GC (0.21%), EGC (0.84%), C (0.61%), EC (2.46%), EGCG (6.90%), CG (0.10%), non-ester catechins (4.11%), ester-catechins (13.44%) and total catechins (17.55%) decreased notably in Pu-erh raw tea with longer storage time, while the content of gallic acid (0.38%) increased significantly. Pu-erh raw tea with longer storage time significantly reduced the activity of AST in the serum (21.49 U/L) but improved the content of GSH (77.28 μmol/gprot) and the activity of SOD in the liver of aged mice; In addition, it reduced the activity of AST and the content of MDA in the liver of aged mice, but the levels were not significant. Pu-erh raw tea with shorter storage time significantly reduced the activity of AST in the serum (29.50 U/L) of aged mice, improved the activity of SOD and GSH content, reduced the activities of ALT and AST and the MDA contents of liver and serum, but the levels were not significant. 【Conclusion】 As the increase of storage time, the contents of water extraction, amino acids, caffeine and catechins decreased notably, while gallic acid increased significantly. Pu-erh raw tea stored at different times both have antioxidant effect on the aged mice. Besides, Pu-erh raw tea with longer storage time had better ability to enhance the activity of antioxidant enzymes SOD and GSH in vivo. [ABSTRACT FROM AUTHOR]

In this study, using 10 Cerasus humilis as test materials, the changes of total proanthocyanidin content and tannin content during fruit development were analyzed. Taking Jin'ou 1 with high content of proanthocyanidin and DS-1 with low content of proanthocyanidin, change of components and contents, and accumulation of proanthocyanidin were analyzed, also correlation between proanthocyanidin components and fruit antioxidant capacity was probed in order to provide a reference for further improvement of quality and development of Cerasus humilis. The results showed that the content of proanthocyanidins and tannins in the fruits of 10 Cerasus humilis showed a downward trend during the fruit development period, and the content of procyanidins in Jin'ou 1 was the highest and that in DS-1 was the lowest. Procyanidin B1(PCB1), procyanidin B2(PCB2), procyanidin A1(PCA1), procyanidin A2(PCA2), catechin(CC), and epicatechin(EC) were all detected in Jin'ou 1 and DS-1. During the whole fruit development period, the content of proanthocyanidin B2(PCB2) in the fruits of the two Cerasus humilis varieties was basically stable, and the contents of other components showed a downward trend. The content of PCA1 in DS-1 was higher than that in Jin'ou 1, and the contents of other components were lower than those in Jin'ou 1. The three antioxidant capacity including DPPH, ABTS+, and FRAP of the two varieties decreased with the fruit ripening, and the antioxidant capacity was significantly positively correlated with total proanthocyanidin and procyanidin B1(PCB1), was extremely significantly positively correlated with catechin(CC) and epicatechin(EC). [ABSTRACT FROM AUTHOR]

The experiment was to study the composition and its antioxidant and bacteriostatic activities of Ficus polyphenols. Using dried Ficus as raw materials, the composition of Ficus polyphenols was identified by FTIR and HPLC. The total reducing power and the scavenging ability of DPPH·and ABTS+·as well as the inhibition zone, MIC and MBC were determined. The results showed that Ficus polyphenols contained polyphenolic hydroxyl, C--H, carbonyl, aromatic ring skeleton, glycosidic bonds and other substances, and the content of gallic acid and catechin were 2.873 and 42.013 mg/L, respectively. The IC50 values of DPPH·and ABTS+·scavenging ability of Ficus polyphenols were 0.090 and 0.143 g/L, respectively, which were similar to those of vitamin C. The results of the inhibition zone assay showed that the inhibitory ability of Ficus polyphenols on the test strains was ranked as follows: Bacillus subtilis > Escherichia coli > Staphylococcus aureus. The MIC of fig polyphenols against Escherichia coli, Bacillus subtilis and Staphylococcus aureus were 0.625 0, 0.625 0, 1.250 0 g/L, respectively, and the MBC were 0.625 0, 1.250 0, and 1.250 0 g/L, respectively. The study indicates that Ficus polyphenols have good antioxidant capacity and antibacterial activity. [ABSTRACT FROM AUTHOR]

The root of Kadsura coccinea is a commonly used herb in traditional Chinese medicine, and flavonoids are one of the main active constituents of medicinal plants. This study intended to investigate whether the leaves and stems of K. coccinea plants may contain similar or highly enriched flavonoids in roots and to explore its application value. Widely-targeted metabolomics was used to identify the compounds in different organs of K. coccinea. According to their structural distribution and categories, the diversity and abundance of flavonoids were analyzed. The results were as follows:(1)The number of flavonoids metabolites in K. coccinea was sorted in descending order as leaf(80)> stem(73)> root(67), and a total of 61 flavonoids were the same in three parts. Leaves and stems contained more flavonols, contributing to a diversity of flavonoids greater than that in the roots.(2)Flavonols, flavonoids, flavanols, and chalcones were highly accumulated in the three parts. Among them, the accumulation of flavonols and flavonoids was lower in the stems and roots, resulting in a continuously, substantially decreasing abundance of flavonoids from leaf(24.00 × 107)to stem(13.45 × 107)to root(9.05 × 107).(3)Leaves and stems of K. coccinea contained a large amount of flavonoids that were also found in the roots and a variety of those not found in the roots, which could be considered for alternative or complementary use. Catechins highly expressed in all three parts, and the leaves were also rich in quercetin and its derivatives, which were highly valuable in application. [ABSTRACT FROM AUTHOR]

To establish the method for determination of gallic acid and catechin in the roots of Rosa laevigata, and to analyze the difference in the contents of gallic acid and catechin in roots of R. laevigata from different habitats and different processed methods resources from Guangxi. The contents of gallic acid and catechin of R. laevigata were used as evaluation index, the samples were determined by HPLC, and the data were analyzed by the analysis of variance(ANOVA)and discrimination study carried out based on the hierarchical clustering analysis(HCA)with SPSS 23.0 software. The results were as follows: The contents of gallic acid and catechin in roots of R. laevigata from different habitats and processed methods were different, the content of catechin was higer than that of gallic acid among all samples, the contents of gallic acid and catechin in roots of R. laevigata from the southern habitats(except for Guiping, Guigang)were generally higher than those from northern habitats, the contents of gallic acid and catechin were the highest in vinegar-processed products. The conclusion display that the differences of gallic acid and catechin contents in the roots of R. laevigata are mainly the differences of producting habitats and processed methods, the HPLC method is simple and feasible, which can provide a scientific basis for the resources development, quality control and clinical application of R. laevigata. [ABSTRACT FROM AUTHOR]

Tn order to better preserve the nutritional value of food and extend the shelf life, using green and safe plant extracts anisic acid and catechins as the main antibacterial raw materials, and polypropylene (PP) as the main base material, modified film is prepared by unifor mLy mixing with titanic acid coupling agent, and granulating and casting. The effect of changes in the content of anisic acid and catechins on the antibacterial properties, mechanical properties, and microstructure of polypropylene films is studied. The results show that when 3% mass fraction of anisic acid and catechin are added, the antibacterial effect is the best. Compared with the control group, the OT) value of E. coli decreases by 30% at 24 h, and the dry weight of black mold is reduced by 48% at 72 h, demonstrating good antibacterial properties. And the mechanical properties and microscopic results have not changed significantly. Through the test of orthogonal experiment, the film still has continuous antibacterial property in a certain period of time. Compared with traditional food additives, plant extracts not only maintain antibacterial properties, but also improve safety, which can meet the needs of daily food packaging. [ABSTRACT FROM AUTHOR]

[Objective] The effect of raw material tenderness on the quality of scented rose black tea was studied in order to further optimize the processing technology of rose black tea and provide theoretical basis for improving the quality of rose black tea. [Method] To scent Damascus rose black tea with tea dhool of different tenderness, the effect of the raw material tenderness of tea dhool on the quality of scented rose black tea was discussed from the aspects of sensory quality, main biochemical components and aroma components. [Result] The content of tea polyphenols, catechins and their main components, EGCG, free amino acids and theanine were significantly reduced after scenting, and the reduction was the greatest when the tenderness of green tea was one bud with two leaves and three leaves, reaching 12. 54%, 24. 90%, 25. 71 %, 12. 54%, 17. 26%,respectively. While the content of soluble carbohydrates increased significantly after scenting, and the increase was the largest when the tenderness of tea body was one bud with two and three leaves,reaching 16. 51 %. The change in composition was the main reason for the decrease in freshness of rose black tea soup, but the decrease in bitterness and astringency, and the increase in sweetness. The theafucin content increases significantly after scenting, and the tenderness of tea greens from single bud to one bud with two and three leaves increased by 12. 72%,5. 93%, and 13. 09%, respectively. This was the main reason for the increase in the color depth of the rose tea soup and the decrease in brightness; The newly produced β-citronellol, methyl eugenol and phenylethyl alcohol with the significant increase of relative content after scenting were the main aroma component of rose black tea, and the relative total amount reached 77. 66 %, when the tea green was one bud with two and three leaves. The substantial decrease in the relative content of geraniol and linalool was the main reason for the decrease in the sweetness of rose black tea. [Conclusion] One bud with 2 or 3 leaves tea blanks showed a better scenting effect of rose black tea. [ABSTRACT FROM AUTHOR]

[Objective] The purpose of this study was to study the quality components of green tea processed by a new variety of Camellia sinensis. [Method] The contents of biochemical components, catechin components, free amino acids and aroma compounds of green tea processed by three different yellow strains of Sichuan tea plant were analyzed as the research object and Fuding dabai as the control group.[Result] The Jinfeng series, a new yellow strain of tea tree, was suitable for processing green tea (phenolic ammonia ratio was less than 8), and there were significant differences between the quality components of green tea and the control. The content of water extract, free amino acid, tea polyphenols and soluble sugar was all higher than that of the control group, while the content of caffeine was all lower than that of the control group except jinfeng 2, and the total amount of catechin was high or low. The predominant catechin content of Jinfeng 1 was C (6.58%), EGC (3.14%) and EC(1.13%), of Jinfeng 2 were EGC (3.14%) and EC (1.13%), and the EGCG content of Jinfeng 3 was the highest（10.12%）.The EGCG content of the yellow tea strain was higher than that of the control group. The free amino acids were mainly umami amino acids（γ-aminobutyric acid, aspartic acid, glutamic acid, theanine and asparagine), and the content ranged from high to low is Jinfeng 2 (2.53%)>Jinfeng 3(2.02%) >Fuding Dabai(2.11%) > Jinfeng 1(1.97%).The number of aroma compounds in the yellow strain was significantly higher than that in the control group, among which the neophytadiene, Butyric acid-reverse-2-hexene ester, Hexanoic acid-cis-3-hexene ester, β-ionone, α-terpineol and δ-cadinene were the important aroma substances that were different from Fuding Dabai in the yellow strain. [Conclusion] The main quality components of the yellow strains of tea were discussed, which provided a theoretical basis for the breeding of new yellow strains, the quality research and the optimization of processing technology. [ABSTRACT FROM AUTHOR]

Objective To study the protective effect of epicatechin (EC) on cerebral ischemia-reperfusion in rats and its influence on antioxidant capacity. Methods Ninety male SD rats were divided into 6 groups according to the random number table method, with 15 rats in each group, namely the sham operation group (Sham group), the model group (I/R group), EC 5 mg/kg group, EC 10 mg/kg group, EC 20 mg/kg group and edaravone 3 mg/kg group (ED 3 mg/kg group). Except for the Sham group, the other groups were established the middle cerebral artery embolism (MCAO) model by the thread embolization method. After the ischemia for 2 h, the drug was administered at the time points of 0 h, 12 h and 24 h after reperfusion. The Longa neurological function score was performed at the 12th and 24th hour. Triphenyltetrazolium chloride (TTC) was used to detect the infarct area of the ischemic side of the brain at the 36 h. Hematoxylin eosin (H&E) staining was used to observe the morphological changes of the ischemic side of the brain. Colorimetric method was used to detect the content of malondialdehyde (MDA), the activity of superoxide dismutase (SOD) and the activity of glutathione peroxidase (GPx) in the serum and the brain tissue of ischemic side of the brain. Results Compared with the Sham group, the neurological function score and the percentage of infarct area were increased in the I/R group (P＜0.05). The tissue morphology was significantly changed, the serum and brain tissue contents of MDA were increased, while the activity of SOD was decreased (P＜0.05). The activity of GPx was decreased in brain tissues (P＜0.05). Compared with the I/R group, the neurological function scores and the percentage of infarct area were decreased in the EC 10 mg/kg group, EC 20 mg/kg group and ED 3 mg/kg group (P＜0.05). The tissue damage was improved. The content of MDA in serum and brain tissue decreased, while the activity of SOD increased (P＜0.05). The activities of GPx in brain tissues increased in EC 10 and 20 mg/kg group and ED 3 mg/kg group (P＜0.05). Conclusion Epicatechin can resist cerebral ischemia-reperfusion injury by enhancing brain antioxidant capacity in rats, which is dose-dependent within a certain range. [ABSTRACT FROM AUTHOR]

Objective To observe the effect of epigallocatechin gallate (EGCG) on small intestine lesions in type 2 diabetic rats. Methods 30 healthy male Wistar rats were selected in October 2019,6 of them were not successful or did not meet the requirements. They were divided into normal control group,model control group and EGCG treatment group,with 8 mice in each group. The high-fat diet combined with streptozotocin was used to replicate type 2 diabetic rats,then successful model animals were randomly divided into the model control group and the EGCG treatment group (100mg/kg). After one month of intragastric administration, fasting blood glucose (FBG),the levels of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in the small intestine of rats were measured,and the pathological changes in the small intestine were observed by HE staining. Results Compared with the normal control group,the small intestinal mucosa of rats in the model control group was significantly damaged;FBG,MDA in the small intestine increased,while SOD activity decreased in the model control group with statistical significance (P <0.05). Compared with the model control group,the damage degree of small intestinal mucosa of rats was significantly reduced in EGCG treatment group;FBG,MDA in the small intestine decreased while SOD activity increased in EGCG treatment group with statistical significance (P <0.05). Conclusion EGCG could significantly improve the small intestinal lesions in type 2 diabetic rats,and the mechanism may be related to the decrease of blood glucose and the reduction of oxidative stress in small intestinal tissues. [ABSTRACT FROM AUTHOR]

To investigate the quality status of Sichuan Gongfu black tea and provide data support for improving the quality of Sichuan Gongfu black tea. [Method] In this study, 64 Kungfu black tea samples from the main tea areas in Sichuan Province were taken as the survey objects, and their sensory quality (shape, aroma, taste, soup color, leaf bottom) and physical and chemical components (gallic acid, caffeine, catechins) were investigated., Theaflavins) for comparative analysis, and draw the taste, aroma and flavor wheel. [Results] The flavor characteristics of Chuanhong Gongfu are mainly "sweet" and "mellow". The total sensory evaluation score is between 83.35 and 91.27, and the evaluation score is basically consistent with the price trend. The flavor wheel shows that the aroma types of Chuanhong Gongfu include fresh, floral, fruity, sweet, etc.; the flavor types include "strong", "mellow", "fresh", "sweet", "thick", etc., but a certain proportion of products have "high fire" "Smoke", "Coke", "Bitter", "Astringent" and other quality defects. Its quality components are trans-catechin content of 24.9～92.25 mg/g, cis-catechin content of 18.37～86.79 mg/g, theaflavin content of 9.03～26.33 mg/g, and caffeine content of 27.92～44.91 mg /g, the gallic acid content is 0.36～7.7 mg/g. Among them, the catechin, theaflavins and gallic acid content (mean value) of the northern Sichuan tea area are the highest compared to the western and southern Sichuan tea areas, while the caffeine content (mean value) is the lowest. [Conclusion] Among the collected tea samples, the comprehensive evaluation of Gongfu black tea quality in the northern Sichuan tea area is the best, but the overall lack of black tea products with excellent sensory qualities such as special flavor types. Therefore, it is recommended to strengthen independent selection and appropriate introduction of tea varieties with flower and fruit aroma, and combine with the main planted varieties in Sichuan to carry out research on different fermentation levels based on different maturity of raw materials and drying and flavoring. [ABSTRACT FROM AUTHOR]

Huangshan Maofeng tea has become one of the most famous Chinese tea due to its amazing orchid fragrance and fresh, sweet taste. However, different quality grades of Huangshan Maofeng tea vary greatly in price. The quality evaluation of tea has posed a great challenge in the tea market. The quality grades of variant tea are also related to the different microelements and concentrations. Traditional sensory evaluation methods cannot achieve fast and accurate discrimination, particularly depending on the manual experience. Alternatively, the chemical analysis can serve as an essential method for the quality evaluation of tea. But the chemical analysis for all microelements was confined to its complexity and time-consuming in a large-scale production under gradually refined detection standards with the fast expansion of tea market. Previous studies reveal that the samples collected from the same production or origin places have the similar microelement compositions and concentrations, indicating that the variation of tea grades depends only on a few types of microelements. Therefore, it is reasonable to select the typical microelements for the distinguishing performance, thereby to optimize the traditional chemical analysis. In this work, a new method was proposed based on the feature extraction using the Elastic Net, in order to simplify the procedure of conventional chemical analysis, while to improve the grade evaluation. First, 96 samples of Huangshan Maofeng tea were collected from three original places (Fuxi, Yangcun, and Xintian village) with 6 quality grades (advance 1-3 grades, and 1-3 grades) using the traditional manual process. The chemical analysis was used to analyze the types and contents of 19 microelements. Second, a cross-validation method was used to determine the optimal parameters in the Elastic Net, and 9 feature microelements (Gallic Acid, Epicatechin Gallate, Catechin, Epicatechin, Gallocatechin Gallate, Epigallocatechin, Glutamate, Arginine and catechins bitterness index) were selected when the cost function was minimized. Third, the radar chart was used to visualize the selected 9 microelements, indicating the tea grade evaluation. To quantify the classification, a quality grade evaluation model of Huangshan Maofeng tea was established on the selected feature microelements using partial least squares regression. Monte-Carlo method with 100 times was chosen to evaluate the stability and robustness of the presented model. The proposed method can reduce the number of microelements from 19 to 9, and thereby to improve the identification accuracy of quality grade evaluation from 69.55% to 79.31%, compared with the traditional chemical analysis. A principal component analysis (PCA) was also taken for comparison. The recognition accuracies of PCA and the proposed method for validation set were 70.79% and 78.72% respectively in the Monte-Carlo experiment. The experimental results demonstrated that the selection of feature microelements was feasible to simply the traditional chemical analysis, and improve the prediction performance. The analysis model based on the typical microelements can simplify the current chemical process, and thereby provide a flexible selection to the quality identification of tea. [ABSTRACT FROM AUTHOR]

Drying is an essential procedure in the processing of fresh tea leaves, in order to enhance the flavors of a tea and ensure its long shelf-life, for making herbal tea. This paper aims to study the effect of temperature and duration on the characteristics and quality of congou black tea during hot-air second drying. An experiment was performed on four second-drying temperatures of 130, 110, 90 and 70 ℃, to determine the contents of biochemical components (water content, catechins, tea pigment, tea polyphenols, caffeine, amino acids, soluble sugar), and thereby to evaluate sensory quality when the tea was dried to 10, 20, 30, 40, 50 and 60 min. The drying characteristics of congou black tea were analyzed under different second-drying temperatures, to obtain the influence of second-drying conditions on the biochemical components and sensory quality of congou black tea. Partial least squares discriminant analysis (PLS-DA) was used to explore the key differential components of second-drying temperature. The results showed that the higher the second-drying temperature, the lower the moisture content of tea, and the higher the drying rate would be, as well the shorter the drying time would be until the moisture content was less than 5%. In terms of drying rate, the drying process at 130 ℃ could be divided into two stages of acceleration and deceleration, while the drying process at 110, 90 and 70 ℃ could be divided into three stages of acceleration, deceleration and constant velocity, where the rapid acceleration and deceleration process were completed within 20min in all second-drying temperature conditions. The effective diffusion coefficient of moisture varied from 1.729×10-8 to 3.648×10-8 m²/s, while the average activation energy was 15.40 kJ/mol. The Page model can well describe the change of moisture with the drying time in the drying process of tea, where the coefficient of determination (R²) ranged from 0.924-0.995, the root-mean-square (RMSE) ranged from 0.008~0.023, the sum of squares (χ²) ranged from 1.043×10-4-7.866×10-4. With the increase of second-drying temperature, the content of some biochemical components would significantly enhance, including (−)-Epogallocatechin, (+)-Catechin, (−)-Gallocatechin, total simple catechins, (−)-Epigallocatechin Gallate, (−)-Gallocatechin Gallate, total ester catechins, total catechins, tea polyphenols, caffeine, whereas, the content of theaflavins, amino acids, soluble sugar would be reduced, where all changed dramatically before drying 20 min. Compared with that of 130 and 110 ℃, the case of the second-drying temperature at 90 and 70 ℃ can better improve the quality of congou black tea. The optimal liquor color effect, aroma effect and taste effect can be achieved in the case of 90 ℃ drying 20-30 min, 70 ℃ drying 40-50 min, 70 ℃ drying 20 min, respectively. The condition of 90 ℃ drying 40 min was the optimum drying parameter of black tea. PLS-DA results showed that four kinds of second-drying temperature conditions could be effectively distinguished, and the caffeine, soluble sugar, amino acid, catechin C and theaflavins were the distinctive characteristic components of congou black tea under different second-drying conditions, which can be served as the control indexes for the drying process of black tea. This finding can provide a theoretical basis to optimize the processing parameters of high-quality black tea. [ABSTRACT FROM AUTHOR]

[Objective]The effect of optimized fertilization technology on tea quality in Pu’er modern tea plantation was studied, which provided the theoretical basis for promoting tea quality. [Method] The national registered tea cultivars ( Yunkang 14) was used as experiment material, four plot experimental treatments including no fertilizer (blank control) , conventional fertilization (positive control) and two different fertilization mode were designed. [ Results]Compared with blank control, fertilizer could improve the tea contains substances. Compared with positive control, treatment with fertilization could obviously improve the contents of tea water extract, tea polyphenols, amino acid, caffeine and catechins, and the content of catechins increased from 1.36 % to 1.93 % , and C, EC and EGC in catechins increased by 0.3 % -0.46 % , 0.24 % -0.33 % , 0.24 % -0.46 % , respectively. The contents of tea catechins and C, EC and EGC in treatments with fertilization were significantly higher than that in blank control, treatment with optimized fertilization had best effeet. [ Conclusion ] Optimal fertilization technology in modern tea garden could significantly improve the tea quality and should be popularized in modern tea plantation. [ABSTRACT FROM AUTHOR]

【Objective】 The present paper aims to study the genetic diversity of wild tea catechins in Yunnan province and provide a theoretical basis for breeding special tea tree resources. 【Method】The components of catechin for 100 Yunnan wild tea tree resources were detected and the component contents of eight major catechins were analyzed by using high performance liquid chromatography (HPLC) method. 【Result】 The components of tea catechins tested had rich diversity and variation，Its variation coefficient ranged from 0. 2912 % to 0. 5669 %. 100 wild tea tree resources by clustering were divided into group A and group B according to catechin components of wild tea tree resources. 【Conclusion】 Group A with the low content of ester type catechins was used to product black tea. Group B showed a high content of ester type catechins. Five quality varieties (Andingyecha，Huangnihedacha，Xisheludacha，Badaerhao and Mengyangcongcha) with the high content of ester type catechins were found and used to product green tea. Four varieties (Zhashangdachashu，Shibalianshandacha，Diweibaimaocha and Longshucha) showed the lower of nonester type catechins as well as the lowest of ester type catechins. Daheishan wild tea had the highest of nonester type catechins. They could be used as breeding special varieties and specific germplasm materials. [ABSTRACT FROM AUTHOR]

The main quality chemical composition of water extract, tea polyphenols and total free amino acid were studied in 35 sun-dried tea of ancient tea plants from south Yunnan. The catechins and caffeine were separated by high performance liquid chromatography. The sun-dried tea of ancient tea plants in different places made the dynamic clustering analysis through the major components analysis method. The results showed that the average contents of water extract, tea polyphenols, total free amino acid and caffeine were 46. 95 %, 22. 76 %, 2. 49 %, 3. 45 %, 8. 3 % and 0. 13 % respectively, and their variable coefficient were 4. 58 %, 8. 14 %, 22. 24 %, 24. 06 %, 19. 31 % and 29. 85 %, respectively. The SNK multiple comparison results showed that the average content of the same chemical component were significantly different in the sun-dried tea of ancient tea plants of different regions. The cluster analysis results showed that the samples were divided into 6 classes. The results showed that the content of the main quality chemical composition of sun-dried tea of ancient tea plants was rich and varied. [ABSTRACT FROM AUTHOR]

Objective:To investigate the effect and mechanism of EGCG on human ovarian cancer SKOV3 cells′ apoptosis. Methods:SKOV3 cells were divided into four groups. Negative control group: cultured with normal culture medium; EGCG low dose group: cultured with 1 μmol/L EGCG; EGCG middle dose group: cultured with 10 μmol/L EGCG; EGCG high dose group: cultured with 100 μmol/L EGCG. Cell proliferation inhibition rate of each group of SKOV3 cells were test by MTT assay, nuclei apoptosis were checked by Hoechs staine, cells morphology were investigated by electron microscope, Caspase-3 expression was detected by Western-blot. Results:Cell proliferation inhibition test results showed that the inhibition rate of EGCG low, medium and high concentration group on SKOV3 cells was (81.33±3.71)%, (67.00±7.21)% and (54.67±3.84)%, the difference was statistically significant (P<0.05) compared with the negative control group (101.00±3.06)%. Hoechst33258 staining results showed that, apoptosis cell percentage of EGCG low, medium and high concentration group was (16.77±2.48)%, (24.33±3.70)% and (39.67±4.11)%, the difference was statistically significant (P<0.05) compared with the negative control group [(2.00±1.45)%]. Electron microscopy showed that with the concentration of EGCG elevated, the damage on ultrastructure of SKOV3 cell became clear. In addition, EGCG could raised Caspase-3 expression levels. Conclusions:EGCG induced ovarian cancer SKOV3 cells apoptosis by enhancing the expression of Caspase-3 gene. [ABSTRACT FROM AUTHOR]

Objective To isolate and identificate the flavonoids from Prinsepia Utilis Royle. Method The chemical compounds were isolated and purified with column chromatographic methods, and identified by ESI-MS, 1H-NMR and 13C-NMR. Results Multiple compounds were isolated, and four compounds among them were flavonoids which were identified as quercetin (I), eriodictyol (II), kaempferol (III),(+) -catechin (IV). Conclusion Four flavones compounds were isolated from Prinsepia Utilis Royle, among them the compounds II~IVwere isolated from prinsepia utilis for the first time. [ABSTRACT FROM AUTHOR]