Effects of electromagnetic roller-hot-air-steam triple-coupled fixation on reducing the bitterness and astringency and improving the flavor quality of green tea.

Despite the importance of fixation in determining green tea quality, its role in reducing the bitter and astringent taste of this beverage remains largely unknown. Herein, an electromagnetic roller-hot-air-steam triple-coupled fixation (ERHSF) device was developed, and its operating parameters were optimized (steam volume: 20 kg/h; hot-air temperature: 90 °C; hot-air blower speed: 1200 r/min). Compared with conventional fixation treated samples, the ratio of tea polyphenols to free amino acids and ester-catechins to simple-catechins in ERHSF-treated samples was reduced by 11.0% and 3.2%, reducing bitterness and astringency of green tea; amino acids, soluble sugars, and chlorophyll contents were significantly increased, enhancing the freshness, sweetness, and greenness; the color indexes, such as L/L* value of brightness and -a/-a* value of greenness, were also improved, and ERHSF-treated samples had the highest sensory scores. These results provided theoretical support and technical guidance for precise quality improvement of summer-autumn green tea.

New insights into the effect of fermentation temperature and duration on catechins conversion and formation of tea pigments and theasinensins in black tea.

BACKGROUND: The phenol oxidative pathway during fermentation remains unclear. To elucidate the effect of fermentation on phenol conversion, we investigated the effects of fermentation temperature and duration on the conversion of catechins and the formation of theasinensins (TSs), theaflavins (TFs), thearubigins (TRs), and theabrownins (TBs). RESULTS: During fermentation, TSs formation increased initially and then decreased. Long fermentation durations were unfavorable for liquor brightness (LB) and resulted in the production of large amounts of TRs and TBs. Low fermentation temperatures (20 °C and 25 °C) favored the maintenance of polyphenol oxidase activity and the continuous formation of TFs, TSs, and TRSI (a TRs fraction), resulting in better LB and liquor color. Higher temperatures (30 °C, 35 °C, and 40 °C) resulted in higher peroxidase activity, higher oxidative depletion rates of catechins, and excessive production of TRSII (a TRs fraction) and TBs. Analysis of the conversion pathway of polyphenolic compounds during fermentation showed that, during early fermentation, large amounts of catechins were oxidized and converted to TFs and theasinensin B. As fermentation progressed, considerable amounts of theaflavin-3'-gallate, theasinensin A, theaflavin-3-gallate, theaflavin-3,3'-digallate, and theasinensin C were produced and then converted to TRSI; in the final stage, TRSII and TBs were converted continuously. CONCLUSION: Different fermentation temperature and duration combinations directly affected the type and composition of phenolic compounds. The key conditions for controlling phenolic compound conversion and fermentation direction were 60 or 90 min and 25 or 30 °C. Our study provides insights into the regulation of phenolic compound conversion during black tea fermentation. © 2021 Society of Chemical Industry.

Rapid characterization of the volatile profiles in Pu-erh tea by gas phase electronic nose and microchamber/thermal extractor combined with TD-GC-MS.

Aroma plays an important role in the quality of Pu-erh tea. However, the quality evaluation of Pu-erh tea aroma is heavily relied on the experience of sensory evaluation, and the theoretical research is relatively scarce. In the present work, the volatile compounds in Pu-erh tea were characterized by using gas phase electronic nose (e-nose) and microchamber/thermal extractor (µ-CTE) combined with thermal desorption coupled to gas chromatography-mass spectrometry (TD-GC-MS). A satisfactory discrimination model (R2 Y = 0.95, Q2  = 0.807) was obtained by using orthogonal partial least squares discriminant analysis (OPLS-DA) based on the odor fingerprint of different brands of Pu-erh tea. In addition, based on the double criterion of multivariate analysis with VIP >1.0 and univariate analysis with p ≤ 0.001, 39 volatile components were identified to contribute greatly to the discrimination of five brands of Pu-erh tea. The results suggested that gas phase e-nose and µ-CTE combined with TD-GC/MS were simple, rapid techniques to characterize the volatile compounds in Pu-erh tea and were allowed to effectively distinguish different brands of Pu-erh tea, which would provide an important reference on the quality assessment of Pu-erh tea. PRACTICAL APPLICATION: This work demonstrates that the volatile compounds in Pu-erh tea are simply and rapidly characterized by using µ-CTE/TD-GC/MS and gas phase e-nose, allowing to effectively distinguish different brands of Pu-erh tea, which can provide an important reference for the quality assessment and authentication of Pu-erh tea.

Aroma dynamic characteristics during the process of variable-temperature final firing of Congou black tea by electronic nose and comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry.

The drying technology is crucial to the quality of Congou black tea. In this study, the aroma dynamic characteristics during the variable-temperature final firing of Congou black tea was investigated by electronic nose (e-nose) and comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOFMS). Varying drying temperatures and time obtained distinctly different types of aroma characteristics such as faint scent, floral aroma, and sweet fragrance. GC × GC-TOFMS identified a total of 243 volatile compounds. Clear discrimination among different variable-temperature final firing samples was achieved by using partial least squares discriminant analysis (R2Y = 0.95, Q2 = 0.727). Based on a dual criterion of variable importance in the projection value (VIP > 1.0) and one-way ANOVA (p < 0.05), ninety-one specific volatile biomarkers were identified, including 2,6-dimethyl-2,6-octadiene and 2,5-diethylpyrazine with VIP > 1.5. In addition, for the overall odor perception, e-nose was able to distinguish the subtle difference during the variable-temperature final firing process.

Rapid determination by near infrared spectroscopy of theaflavins-to-thearubigins ratio during Congou black tea fermentation process.

The theaflavin-to-thearubigin ratio (TF/TR) is an important parameter for evaluating the degree of fermentation and quality characteristics of Congou black tea. Near infrared (NIR) spectroscopy, one of the most promising techniques for evaluating large-scale tea processing quality, in association with chemometrics, can be used as a selection tool when a fast determination of the requested parameters is required. The aim of this work is to develop a unique model for the determination of TF/TR. First, 11 key wavelength variables were screened by synergy interval partial least-squares regression (SI-PLS) and competitive adaptive reweighted sampling (CARS). Based on these characteristic variables, a new extreme learning machine (ELM) combined with an adaptive boosting (ADABOOST) algorithm (ELM-ADABOOST) was applied to construct the nonlinear prediction model for TF/TR, and an independent external set was used for the validation. A determinate coefficient (Rp2) of 0.893, root mean square error of prediction (RMSEP) of 0.0044, RSD below 10%, and RPD above 3 were acquired in the prediction model. These results demonstrate that NIR can be used to rapidly determine the TF/TR value during fermentation, and it effectively simplify the model and improve the prediction accuracy when combined with the SI-CARS variable.

Far-Infrared Optimization of the Fragrance-Improving Process with Temperature and Humidity Control for Green Tea.

In this study, a Box-Behnken design was used to explore the effect of a new technology on green tea fragrance improvement and to optimize fragrance-improving with a bilayer far-infrared fragrance-improving machine with temperature and humidity control. Based on the results of previous single-factor experiments, the main biochemical composition and sensory evaluation scores of the fragrance-improved samples were used as investigation indices. The new fragrance-improving technology was compared with the traditional far-infrared fragrance-improving process, roller pot fragrance improvement, and hot air rotary fragrance improvement. The results show that the optimal parameter combination of the new technology consists of a temperature of 128.00 °C, relative humidity of 70.00 g/h, and transmission speed of 435.00 r/min. With these process parameters, the amino acids, tea polyphenols, flavonoids, soluble sugar, catechins, and caffeine in the fragrance-improved samples reached 3.86%, 32.29%, 5.59%, 4.45%, 8.97%, and 2.75%, respectively. The quality material weight value was 11.72%. The shape, color, taste, and aroma of the fragrance-improved samples made using these parameters were found to be best, with a sensory quality score of 87.40, which is significantly higher than that of other fragrance-improving methods. The energy consumption was 0.19 RMB/kg, which was reduced by more than 50% compared with the other methods, and the production efficiency was more than 30% higher than the traditional methods. This new far-infrared fragrance-improving technology overcomes the yellowish and grayish color of fragrance-improved tea samples that is caused by the traditional fragrance-improving approach, and will provide technical guidance for actual green tea production. PRACTICAL APPLICATION: Our proposed approach innovatively integrates humidity and rotational speed as factors for fragrance improvement in Chinese tea process. The findings of this work provide new technical for fragrance improvement processes.

Preventive Effects of Catechins on Cardiovascular Disease.

Catechins are polyphenolic phytochemicals with many important physiological activities that play a multifaceted health care function in the human body, especially in the prevention of cardiovascular disease. In this paper, various experimental and clinical studies have revealed the role of catechins in the prevention and treatment of cardiovascular disorders, and we review the preventive effects of catechins on cardiovascular disease from the following aspects: Regulating lipid metabolism, regulating blood lipid metabolism, vascular endothelial protection, and reducing blood pressure.

(-)-Epigallocatechin gallate (EGCG)-nanoethosomes as a transdermal delivery system for docetaxel to treat implanted human melanoma cell tumors in mice.

(-)-Epigallocatechin-3-O-gallate (EGCG), a versatile natural product in fresh tea leaves and green tea, has been investigated as a preventative treatment for cancers and cardiovascular disease. The objective of this study was to develop EGCG-nanoethosomes for transdermal delivery and to evaluate them for treating subcutaneously implanted human melanoma cell tumors. EGCG-nanoethosomes, composed of 0.2% EGCG, 2% soybean phosphatidylcholine, 30% ethanol, 1% Tween-80 and 0.1% sugar esters, were prepared and characterized using laser transmission electron microscopy. These nanoethosomes were smoother and more compact than basic-nanoethosomes with the same components except for EGCG. The effectiveness of transdermal delivery by EGCG-nanoethosomes was demonstrated in an in vitro permeability assay system using mouse skin. The inhibitory effect of docetaxel (DT) loaded in EGCG-nanoethosomes (DT-EGCG-nanoethosomes) was analyzed by monitoring growth of a subcutaneously implanted tumor from A-375 human melanoma cells in mice. Mice treated with DT-EGCG-nanoethosomes exhibited a significant therapeutic effect, with tumors shrinking, on average, by 31.5% of initial volumes after 14 d treatment. This indicated a potential for treating skin cancer. In a pharmacokinetic study, transdermal delivery by DT-EGCG-nanoethosomes enabled sufficient DT exposure to the tumor. Together, these findings indicated that EGCG-nanoethosomes have great potential as drug carriers for transdermal delivery.

CuI/Oxalamide Catalyzed Couplings of (Hetero)aryl Chlorides and Phenols for Diaryl Ether Formation.

Couplings between (hetero)aryl chlorides and phenols can be effectively promoted by CuI in combination with an N-aryl-N'-alkyl-substituted oxalamide ligand to proceed smoothly at 120 °C. For this process, N-aryl-N'-alkyl-substituted oxalamides are more effective ligands than bis(N-aryl)-substituted oxalamides. A wide range of electron-rich and electron-poor aryl and heteroaryl chlorides gave the corresponding coupling products in good yields. Satisfactory conversions were achieved with electron-rich phenols as well as a limited range of electron-poor phenols. Catalyst and ligand loadings as low as 1.5 mol % are sufficient for the scaled-up variants of some of these reactions.

The major factors influencing the formation of sediments in reconstituted green tea infusion.

The effects of Ca(2+), caffeine and polyphenols on the formation of reversible tea sediments (RTS) and irreversible tea sediments (IRS) in green tea infusion were studied. Adding Ca(2+) (2 mmol/l) was found to increase the formation of RTS by 8% and IRS by 92%, while adding chelating ions of Na2EDTA significantly decreased the amount of RTS by 14.6%, but not the amount of IRS. Under acid conditions, Ca(2+) combined with oxalic ions to form indissoluble oxalate that is the principal constituent of IRS, despite the existence of the chelating ions. Decaffeination largely inhibited the formation of RTS (73%) and IRS (60%), even in the presence of Ca(2+). The amount of sediment could be reduced by removing polyphenols using polyvinyl-polypyrrolidone. The results suggest that sediment formation in green tea infusions can be inhibited by lowering the concentration of Ca(2+), caffeine or polyphenols.

Improving the effectiveness of (-)-epigallocatechin gallate (EGCG) against rabbit atherosclerosis by EGCG-loaded nanoparticles prepared from chitosan and polyaspartic acid.

(-)-Epigallocatechin gallate (EGCG) is the major bioactive compound in green tea. Its effect is limited by the harsh environment of the gastrointestinal tract. The present study investigates how the effectiveness of EGCG is influenced by its encapsulation into self-assembled nanoparticles of chitosan (CS) and aspartic acid (PAA). Blank nanoparticles with a mean diameter of ca. 93 nm were prepared from 30-50 kDa PAA and 3-5 kDa CS with a mass rate of 1:1. EGCG was loaded in the nanoparticles to yield EGCG-CS-PAA nanoparticles with an average diameter of 102 nm, which were pH-responsive and demonstrated different EGCG release profiles in simulated gastrointestinal tract media. The average ratio (%) of lipid deposition for EGCG-CS-PAA nanoparticles administered orally to rabbits was 16.9 ± 5.8%, which was close to that of oral simvastatin (15.6 ± 4.1%). Orally administered EGCG alone yielded an average ratio of lipid deposit area of 42.1 ± 4.0%, whereas this value was 65.3 ± 10.8% for the blank nanoparticles. The effectiveness of EGCG against rabbit atherosclerosis was significantly improved by incorporating EGCG into the nanoformulation.

Sociodemographic and health-related risk factors associated with tooth loss among adults in Rhode Island.

INTRODUCTION: Oral health is an integral component of overall health and well-being. Very little Rhode Island state-level information exists on the determinants of tooth loss. The objective of this study was to systematically identify sociodemographic characteristics, health behaviors, health conditions and disabilities, and dental insurance coverage associated with tooth loss among noninstitutionalized adults in Rhode Island. METHODS: We analyzed Rhode Island's 2008 and 2010 Behavioral Risk Factor Surveillance System survey data in 2011. The survey had 4 response categories for tooth loss: none, 1 to 5, 6 or more but not all, and all. We used multinomial logistic regression models to assess the relationship between 4 risk factor domains and tooth loss. RESULTS: An estimated 57.6% of Rhode Island adults had all their teeth, 28.9% had 1 to 5 missing teeth, 8.9% had 6 to 31 missing teeth, and 4.6% were edentulous. Respondents who had low income, low education, unhealthy behaviors (ie, were former or current smokers and did not engage in physical activity), chronic conditions (ie, diabetes and obesity) or disabilities, and no dental insurance coverage were more likely to have fewer teeth compared with their referent groups. However, the association of these variables with tooth loss was not uniform by age group. CONCLUSION: Adults who report risky health behaviors or impaired health may be considered target subpopulations for prevention of tooth loss and promotion of good oral health.

Using disability-adjusted life years to assess the burden of disease and injury in Rhode Island.

OBJECTIVES: Disability-adjusted life years (DALYs) measure the burden of disease and injury in a population. We tested the feasibility of calculating DALYs to assess the burden of disease and injury in Rhode Island (RI). METHODS: We computed DALYs for the 2008 RI population using methods developed by the World Health Organization, Harvard University, and the World Bank. DALYs are a composite measure that sum years of life lost (YLLs) due to premature mortality with years lived with disability (YLDs). We calculated crude mortality, YLLs, YLDs, and DALYs for 90 major health conditions for RI and stratified them by gender and age. Calculations for YLLs and YLDs were based on five-year averages. We compared our results with U.S. and Los Angeles County, California, estimates. RESULTS: A DALYs ranking produces a different picture of RI's disease and injury burden than does mortality-based ranking. Of 90 major health conditions assessed for RI, six of the top 10 causes for mortality and DALYs were the same, but were ranked differently: ischemic heart disease, cerebrovascular disease, Alzheimer dementia and other dementias, trachea/bronchus/lung cancer, chronic obstructive pulmonary disease, and diabetes mellitus. These six conditions accounted for 59% of deaths but only 35% of DALYs. Causes and rank orders for DALYs differed between males and females and among age groups. CONCLUSIONS: Including nonfatal health conditions in an assessment of population health provides a different picture than traditional mortality-based assessments. This study demonstrates the feasibility and constraints of using DALYs to assess the burden of disease and injury at the state level.

A comparison of depression and mental distress indicators, Rhode Island Behavioral Risk Factor Surveillance System, 2006.

INTRODUCTION: Depression is a public health concern that warrants accurate population estimates. The patient health questionnaire 8 (PHQ-8) offers high sensitivity and specificity for assessing depression but is time-consuming to administer, answer, and score. We sought to determine whether 1 of 3 simpler instruments - the shorter PHQ-2 or 2 single questions from the health-related quality of life (HRQOL) module of the Behavioral Risk Factor Surveillance System (BRFSS) - could offer accuracy comparable to the PHQ-8. METHODS: We compared the depression and mental distress indicators of 2006 Rhode Island BRFSS data by using 4 types of analyses: 1) sensitivity and specificity estimates, 2) prevalence estimates, 3) multivariable logistic regression modeling of the relationship between each of the 4 indicators and 11 demographic and health risk variables, and 4) geographic distribution of prevalence. RESULTS: Compared with the PHQ-8, the 3 other measures have high levels of specificity but lower sensitivity. Depression prevalence estimates ranged from 8.6% to 10.3%. The adjusted odds ratios from logistic regression modeling were consistent. Each of the indicators was significantly associated with low income, being unable to work, current smoking, and having a disability. CONCLUSION: The PHQ-8 indicator is the most sensitive and specific and can assess depression severity. The HRQOL and PHQ-2 indicators are adequate to obtain population prevalence estimates if questionnaire length is limited.

Suicide patterns and association with predictors among Rhode Island public high school students: a latent class analysis.

OBJECTIVES: We analyzed Rhode Island's 2007 Youth Risk Behavior Survey (YRBS) data to investigate suicide patterns and their association with suicide risk predictors among public high school students. METHODS: We used latent class regression analysis of Rhode Island's 2007 YRBS data (from a random sample of 2210 public high school students) to model latent classes of suicide risk and identify predictors of latent class membership. RESULTS: Four latent classes of suicide risk were modeled and predictors were associated with each: class 1 (emotionally healthy, 74%); class 2 (considered and planned suicide, 14%) was associated with being female, having low grades, being gay/lesbian/bisexual/unsure, feeling unsafe at school, having experienced forced sexual intercourse, and self-perceived overweight; class 3 (attempted suicide, 6%) was associated with speaking a language other than English at home, being gay/lesbian/bisexual/unsure, feeling unsafe at school, and forced sexual intercourse; and class 4 (planned and attempted suicide, 6%) was associated with the previously mentioned predictors and with being in 9th or 10th grade and currently smoking. CONCLUSIONS: A single model characterized and quantified 4 patterns of suicide risk among adolescents and identified predictors for 3 at-risk classes. Interventions for high-risk youths may help prevent adolescent suicides.

Adolescent suicide and health risk behaviors: Rhode Island's 2007 Youth Risk Behavior Survey.

BACKGROUND: Suicide is the third-leading cause of death among high school students in the U.S. PURPOSE: This study examined the relationships among indicators of depressed mood, suicidal thoughts, suicide attempts, and demographics and risk behaviors in Rhode Island high school students. METHODS: Data from Rhode Island's 2007 Youth Risk Behavior Survey were utilized for this study. The statewide sample contained 2210 randomly selected public high school students. Data were analyzed in 2008 to model for each of five depressed mood/suicide indicators using multivariable logistic regression. RESULTS: By examining depressed mood and suicide indicators through a multivariable approach, the strongest predictors were identified, for multiple as well as specific suicide indicators. These predictors included being female, having low grades, speaking a language other than English at home, being lesbian/gay/bisexual/unsure of sexual orientation, not going to school as a result of feeling unsafe, having been a victim of forced sexual intercourse, being a current cigarette smoker, and having a self-perception of being overweight. CONCLUSIONS: The strength of associations between three factors (immigrant status, feeling unsafe, and having forced sex) and suicide indicators adds new information about potential predictors of suicidal behavior in adolescents.

Thermal effects on the stability and antioxidant activity of an acid polysaccharide conjugate derived from green tea.

A technique of high-performance gel permeation chromatography (HPGPC)-evaporative light-scattering detection and circular dichroism (CD) was developed for the measurement of thermal effects on the homogeneity and conformation of polymeric carbohydrate conjugates and was applied to an acid polysaccharide conjugate (GTa) isolated from the composite enzyme extract of green tea. Incubations in water at 40 and 70 degrees C for 1.0, 2.5, and 5.0 h have no effects on GTa. In contrast, when incubated in water for 1.0, 2.5, and 5.0 h at 98 degrees C, a single symmetrical peak corresponding to GTa in HPGPC was split into two adjacent peaks representing two different components formed, and CD spectra revealed an additional positive Cotton effect at 216 nm. To contribute toward our understanding of thermal effects of this polymeric carbohydrate conjugate on antioxidant activity, GTa and related heat-treated samples (GTa-HTI, GTa-HTII, and GTa-HTIII), the latter being obtained from 1.0, 2.5, and 5.0 h incubations at 98 degrees C, respectively, were subjected to the self-oxidation of 1,2,3-phentriol assay and found to have respective scavenging activities in a concentration-dependent manner. In comparison with GTa, the scavenging potency of heat-treated samples was similar at the dosage range of 50-300 microg/mL but became stronger with continually increasing concentration. Moreover, the present study also provides further insights into the optimal preparation of tea polysaccharide conjugates.

Using item response theory to analyze the relationship between health-related quality of life and health risk factors.

Many researchers have presented results of the relationships between health-related quality of life (HRQOL) indicators (outcomes) and health risk factors using either linear or logistic regression modeling. We combined the results of multiple HRQOL models by using item response theory (IRT) to assess the association between multiple correlated HRQOL indicators and multiple demographic and health risk variables as predictors. The data source for the study was Rhode Island's 2004 Behavioral Risk Factor Surveillance System, which had a sample of 3,999 adults aged 18 years or older. We developed a single model for overall HRQOL by using IRT to assess the association between HRQOL indicators and multiple demographic and health risk variables as predictors. The strongest predictors for overall poor HRQOL were lower income, inability to work, unemployment, smoking, lack of exercise, asthma, obesity, and disability. IRT may serve as a solution for modeling multiple correlated outcomes in epidemiology. Application of IRT to epidemiologic data can help identify at-risk subgroups for targeted interventions.

Patterns of health-related quality of life and patterns associated with health risks among Rhode Island adults.

BACKGROUND: Health-related quality of life (HRQOL) has become an important consideration in assessing the impact of chronic disease on individuals as well as in populations. HRQOL is often assessed using multiple indicators. The authors sought to determine if multiple indicators of HRQOL could be used to characterize patterns of HRQOL in a population, and if so, to examine the association between such patterns and demographic, health risk and health condition covariates. METHODS: Data from Rhode Island's 2004 Behavioral Risk Factor Surveillance System (BRFSS) were used for this analysis. The BRFSS is a population-based random-digit-dialed telephone survey of adults ages 18 and older. In 2004 RI's BRFSS interviewed 3,999 respondents. A latent class regression (LCR) model, using 9 BRFSS HRQOL indicators, was used to determine latent classes of HRQOL for RI adults and to model the relationship between latent class membership and covariates. RESULTS: RI adults were categorized into four latent classes of HRQOL. Class 1 (76%) was characterized by good physical and mental HRQOL; Class 2 (9%) was characterized as having physically related poor HRQOL; Class 3 (11%) was characterized as having mentally related poor HRQOL; and Class 4 (4%) as having both physically and mentally related poor HRQOL. Class 2 was associated with older age, being female, unable to work, disabled, or unemployed, no participation in leisure time physical activity, or with having asthma or diabetes. Class 3 was associated with being female, current smoking, or having asthma or disability. Class 4 was associated with almost all the same predictors of Classes 2 and 3, i.e. older age, being female, unable to work, disabled, or unemployed, no participation in leisure time physical activity, current smoking, with having asthma or diabetes, or with low income. CONCLUSION: Using a LCR model, the authors found 4 distinct patterns of HRQOL among RI adults. The largest class was associated with good HRQOL; three smaller classes were associated with poor HRQOL. We identified the characteristics of subgroups at higher-risk for each of the three classes of poor HRQOL. Focusing interventions on the high-risk populations may be one approach to improving HRQOL in RI.