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1.
Prev Med ; 184: 107997, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38729527

ABSTRACT

OBJECTIVES: Public Health officials are often challenged to effectively allocate limited resources. Social determinants of health (SDOH) may cluster in areas to cause unique profiles related to various adverse life events. The authors use the framework of unintended teen pregnancies to illustrate how to identify the most vulnerable neighborhoods. METHODS: This study used data from the U.S. American Community Survey, Princeton Eviction Lab, and Connecticut Office of Vital Records. Census tracts are small statistical subdivisions of a county. Latent class analysis (LCA) was employed to separate the 832 Connecticut census tracts into four distinct latent classes based on SDOH, and GIS mapping was utilized to visualize the distribution of the most vulnerable neighborhoods. GEE Poisson regression model was used to assess whether latent classes were related to the outcome. Data were analyzed in May 2021. RESULTS: LCA's results showed that class 1 (non-minority non-disadvantaged tracts) had the least diversity and lowest poverty of the four classes. Compared to class 1, class 2 (minority non-disadvantaged tracts) had more households with no health insurance and with single parents; and class 3 (non-minority disadvantaged tracts) had more households with no vehicle available, that had moved from another place in the past year, were low income, and living in renter-occupied housing. Class 4 (minority disadvantaged tracts) had the lowest socioeconomic characteristics. CONCLUSIONS: LCA can identify unique profiles for neighborhoods vulnerable to adverse events, setting up the potential for differential intervention strategies for communities with varying risk profiles. Our approach may be generalizable to other areas or other programs. KEY MESSAGES: What is already known on this topic Public health practitioners struggle to develop interventions that are universally effective. The teen birth rates vary tremendously by race and ethnicity. Unplanned teen pregnancy rates are related to multiple social determinants and behaviors. Latent class analysis has been applied successfully to address public health problems. What this study adds While it is the pregnancy that is not planned rather than the birth, access to pregnancy intention data is not available resulting in a dependency on teen birth data for developing public health strategies. Using teen birth rates to identify at-risk neighborhoods will not directly represent the teens at risk for pregnancy but rather those who delivered a live birth. Since teen birth rates often fluctuate due to small numbers, especially for small neighborhoods, LCA may avoid some of the limitations associated with direct rate comparisons. The authors illustrate how practitioners can use publicly available SDOH from the Census Bureau to identify distinct SDOH profiles for teen births at the census tract level. How this study might affect research, practice or policy These profiles of classes that are at heightened risk potentially can be used to tailor intervention plans for reducing unintended teen pregnancy. The approach may be adapted to other programs and other states to prioritize the allocation of limited resources.


Subject(s)
Geographic Information Systems , Latent Class Analysis , Social Determinants of Health , Humans , Female , Adolescent , Pregnancy , Connecticut , Neighborhood Characteristics , Vulnerable Populations/statistics & numerical data , Residence Characteristics/statistics & numerical data , Pregnancy in Adolescence/statistics & numerical data , United States , Socioeconomic Factors
2.
J Sci Food Agric ; 102(7): 2750-2760, 2022 May.
Article in English | MEDLINE | ID: mdl-34719036

ABSTRACT

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.


Subject(s)
Biflavonoids , Camellia sinensis , Catechin , Antioxidants/analysis , Biflavonoids/analysis , Camellia sinensis/chemistry , Catechin/analysis , Fermentation , Phenol/analysis , Tea/chemistry , Temperature
3.
Angew Chem Int Ed Engl ; 60(13): 7082-7086, 2021 03 22.
Article in English | MEDLINE | ID: mdl-33372348

ABSTRACT

α-(Hetero)aryl nitriles are important structural motifs for pharmaceutical design. The known methods for direct synthesis of these compounds via coupling with (hetero)aryl halides suffer from narrow reaction scope. Herein, we report that the combination of copper salts and oxalic diamides enables the coupling of a variety of (hetero)aryl halides (Cl, Br) and ethyl cyanoacetate under mild conditions, affording α-(hetero)arylacetonitriles via one-pot decarboxylation. Additionally, the CuBr/oxalic diamide catalyzed coupling of (hetero)aryl bromides with α-alkyl-substituted ethyl cyanoacetates proceeds smoothly at 60 °C, leading to the formation of α-alkyl (hetero)arylacetonitriles after decarboxylation. The method features a general substrate scope and is compatible with various functionalities and heteroaryls.

4.
J Am Chem Soc ; 141(8): 3541-3549, 2019 02 27.
Article in English | MEDLINE | ID: mdl-30688450

ABSTRACT

A robust and practical protocol for preparing alkyl aryl ethers has been developed, which relies on using two types of ligands to promote Cu-catalyzed alkoxylation of (hetero)aryl halides. The reaction scope is very general for a variety of coupling partners, particularly for challenging secondary alcohols and (hetero)aryl chlorides. In case of coupling with aryl chlorides and bromides, two oxalic diamides serve as the powerful ligands. The tert-butoxide is first demonstrated as a ligand for Cu-catalyzed coupling reaction, leading to alkoxylation of aryl iodides complete at room temperature. Additionally, a number of carbohydrate derivatives are applicable for this coupling reaction, affording the corresponding carbohydrate-aryl ethers in 29-98% yields.

5.
Molecules ; 24(23)2019 Nov 20.
Article in English | MEDLINE | ID: mdl-31757064

ABSTRACT

The sweet-mellow taste sensation is a unique and typical feature of premium congou black tea infusions. To explore the key taste-active compounds that influence the sweet-mellow taste, a sensory and molecular characterization was performed on thirty-three congou black tea infusions presenting different taste qualities, including the sweet-mellow, mellow-pure, or less-mellow taste. An integrated application of quantitative analysis of 48 taste-active compounds, taste contribution analysis, and further validation by taste supplementation experiments, combined with human sensory evaluation revealed that caffeine, γ-aminobutyric acid, rutin, succinic acid, citric acid, and gallic acid negatively affect the sweet-mellow taste, whereas glucose, sucrose, and ornithine positively contribute to the sweet-mellow taste of congou black tea infusions. Particularly, rutin, γ-aminobutyric acid, gallic acid, and caffeine, which impart the major inhibitory effect to the manifestation of the sweet-mellow taste, were identified as the key influencing components through stepwise screening and validation experiments. A modest level of these compounds was found to be favorable for the development and manifestation of the sweet-mellow taste. These compounds might potentially serve as the regulatory targets for oriented-manufacturing of high-quality sweet-mellow congou black tea.


Subject(s)
Caffeine/analysis , Camellia sinensis/chemistry , Gallic Acid/analysis , Rutin/analysis , Taste , Tea/chemistry , gamma-Aminobutyric Acid/analysis , Camellia sinensis/growth & development , Female , Humans , Male
6.
J Public Health Manag Pract ; 25(2): 137-146, 2019.
Article in English | MEDLINE | ID: mdl-29521848

ABSTRACT

CONTEXT: National data on the epidemiology of firearm injuries and circumstances of firearm deaths are difficult to obtain and often are nonreliable. Since firearm injury and death rates and causes can vary substantially between states, it is critical to consider state-specific data sources. OBJECTIVE: In this study, we illustrate how states can systematically examine demographic characteristics, firearm information, type of wound, toxicology tests, precipitating circumstances, and costs to provide a comprehensive picture of firearm injuries and deaths using data sets from a single state with relatively low rates of firearm injury and death. DESIGN: Cross-sectional study. SETTING: Firearm-related injury data for the period 2005-2014 were obtained from the Rhode Island emergency department and hospital discharge data sets; death data for the same period were obtained from the Rhode Island Violent Death Reporting System. MAIN OUTCOME MEASURE: Descriptive statistics were used. Healthcare Cost and Utilization Project cost-to-charge ratios were used to convert total hospital charges to costs. RESULTS: Most firearm-related emergency department visits (55.8%) and hospital discharges (79.2%) in Rhode Island were from assaults; however, most firearm-related deaths were suicides (60.1%). The annual cost of firearm-related hospitalizations was more than $830 000. Most decedents who died because of firearms tested positive for illicit substances. Nearly a quarter (23.5%) of firearm-related homicides were due to a conflict between the decedent and suspect. More than half (59%) of firearm suicide decedents were reported to have had current mental or physical problems prior to death. CONCLUSIONS: Understanding the state-specific magnitude and patterns (who, where, factors, etc) of firearm injury and death may help inform local injury prevention efforts. States with similar data sets may want to adopt our analyses. Surveillance of firearm-related injury and death is essential. Dissemination of surveillance findings to key stakeholders is critical in improving firearm injury prevention. States that are not part of the National Violent Death Reporting System (NVDRS) could work with their other data sources to obtain a better picture of violent injuries and deaths to make the best use of resources.


Subject(s)
Data Science/standards , Firearms/statistics & numerical data , Registries/standards , Cross-Sectional Studies , Data Science/methods , Emergency Service, Hospital , Humans , Patient Discharge/statistics & numerical data , Population Surveillance/methods , Registries/statistics & numerical data , Research Design , Rhode Island/epidemiology , Violence/statistics & numerical data
7.
J Org Chem ; 83(12): 6589-6598, 2018 06 15.
Article in English | MEDLINE | ID: mdl-29786439

ABSTRACT

The amide derived from 4-hydroxy-l-proline and 2,6-dimethylaniline is a powerful ligand for Cu-catalyzed coupling of (hetero)aryl halides with sulfinic acid salts, allowing the formation of a wide range of (hetero)aryl sulfones from the corresponding (hetero)aryl halides at considerably low catalytic loadings. The coupling of (hetero)aryl iodides and sodium methanesulfinate proceeds at room temperature with only 0.5 mol % CuI and ligand, representing the first example for Cu-catalyzed arylation at both low catalytic loading and room temperature.

8.
J Public Health Manag Pract ; 23(5): 499-506, 2017.
Article in English | MEDLINE | ID: mdl-28009694

ABSTRACT

CONTEXT: Drug overdoses are a growing public health problem in the United States. Rhode Island is also confronted with a serious epidemic of drug overdose deaths and ranks sixth worst in the United States for age-adjusted drug overdose death rate. OBJECTIVE: To monitor trends of drug overdose-related emergency department (ED) visits, hospitalizations, and deaths and classify the drug overdoses by demographics, discharge status, intent, and specific drug involved to plan for health care resource allocation, mental health services, drug abuse treatment, prevention, and policies. DESIGN: Cross-sectional study. SETTING: The 2005-2014 ED, hospital discharge, and death data were used for this study. MAIN OUTCOME MEASURE: Age-adjusted rates were calculated by using age-specific Rhode Island 2010 standard population. Healthcare Cost and Utilization Project cost-to-charge ratios were used to convert total hospital charges to costs. The descriptive analysis was performed. RESULTS: Hospitalizations generally represent the most severe cases; there are substantially fewer cases than are seen in the ED, and their characteristics are different from ED visits. More than half of the ED cases were an unintentional injury by drug overdose, but more than half of the hospital discharge data cases were a suicide/self-inflicted injury by drug overdose. There were typically much more females than males that result in a hospital admission. In Rhode Island, there were 249 drug overdose deaths in 2014. Drug overdose fatalities were more likely to be young, male, white, and those who reside in suburban regions. IMPLICATIONS: Nonfatal and fatal drug overdose data are important for understanding the scope, incidence, and breadth of this public health epidemic and can guide overdose intervention efforts. In Rhode Island, policy makers can use drug overdose data to target high-risk subpopulations to reduce overdose injuries and fatalities. The Rhode Island study can be shared with other states. CONCLUSIONS: Regardless of the type of drug, overdoses remain a public health crisis in Rhode Island. It is a dynamic epidemic and needs partnership among public health, behavioral health, public safety, clinic, pharmacy, and communities. The ability to track drug overdose in real time will be an essential tool to respond to the constantly evolving drug overdose epidemic in Rhode Island quickly and effectively.

9.
Angew Chem Int Ed Engl ; 56(51): 16136-16179, 2017 12 18.
Article in English | MEDLINE | ID: mdl-28544319

ABSTRACT

Metal-catalyzed cross-coupling reactions belong to the most important transformations in organic synthesis. Copper catalysis has received great attention owing to the low toxicity and low cost of copper. However, traditional Ullmann-type couplings suffer from limited substrate scopes and harsh reaction conditions. The introduction of several bidentate ligands, such as amino acids, diamines, 1,3-diketones, and oxalic diamides, over the past two decades has totally changed this situation as these ligands enable the copper-catalyzed coupling of aryl halides and nucleophiles at both low reaction temperatures and catalyst loadings. The reaction scope has also been greatly expanded, rendering this copper-based cross-coupling attractive for both academia and industry. In this Review, we have summarized the latest progress in the development of useful reaction conditions for the coupling of (hetero)aryl halides with different nucleophiles. Additionally, recent advances in copper-catalyzed coupling reactions with aryl boronates and the copper-based trifluoromethylation of aromatic electrophiles will be discussed.

10.
Molecules ; 21(12)2016 Dec 21.
Article in English | MEDLINE | ID: mdl-28009849

ABSTRACT

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.


Subject(s)
Antioxidants/pharmacology , Cardiovascular Diseases/prevention & control , Catechin/pharmacology , Endothelium, Vascular/drug effects , Tea/chemistry , Blood Pressure/drug effects , Cardiovascular Diseases/blood , Cardiovascular Diseases/physiopathology , Endothelium, Vascular/metabolism , Endothelium, Vascular/physiopathology , Humans , Lipid Metabolism/drug effects , Primary Prevention
11.
Angew Chem Int Ed Engl ; 55(21): 6211-5, 2016 05 17.
Article in English | MEDLINE | ID: mdl-27072902

ABSTRACT

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.

12.
J Am Chem Soc ; 137(37): 11942-5, 2015 Sep 23.
Article in English | MEDLINE | ID: mdl-26352639

ABSTRACT

A class of oxalic diamides are found to be effective ligands for promoting CuI-catalyzed aryl amination with less reactive (hetero)aryl chlorides. The reaction proceeds at 120 °C with K3PO4 as the base in DMSO to afford a wide range of (hetero)aryl amines in good to excellent yields. The bis(N-aryl) substituted oxalamides are superior ligands to N-aryl-N'-alkyl substituted or bis(N-alkyl) substituted oxalamides. Both the electronic nature and the steric property of the aromatic rings in ligands are important for their efficiency.


Subject(s)
Amines/chemistry , Chlorine/chemistry , Copper/chemistry , Diamide/chemistry , Iodides/chemistry , Oxalic Acid/chemistry , Catalysis
13.
Prev Med ; 73: 139-44, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25602912

ABSTRACT

OBJECTIVE: Most departments of health grapple with how to most effectively allocate resources to address chronic diseases. We adapted a model created by Massachusetts to create customized city/town profiles in order to identify the patterns of chronic disease among 39 cities/towns in Rhode Island. METHODS: We used four data sources to identify 20 indicators of four domains: demographics and socioeconomic status; health behaviors and chronic diseases prevalence; no regular provider and non-emergent emergency department visits; and chronic disease-related hospitalizations. A latent class model was used to group cities/towns into distinct latent class memberships based on similar patterns of indicators. Data were analyzed in 2014. RESULTS: The latent class model differentiated three distinct classes of city/town, reflecting three levels of economic and health indicators. CONCLUSIONS: Our model was a simplified version of one constructed by Massachusetts that larger states can also use to understand chronic disease patterns among cities/towns. Chronic disease programs and policies can use the findings to direct resources toward targets not always identified by more traditional analyses.


Subject(s)
Chronic Disease/epidemiology , Models, Statistical , Urban Population/statistics & numerical data , Behavioral Risk Factor Surveillance System , Emergency Service, Hospital/statistics & numerical data , Hospitalization/statistics & numerical data , Humans , Rhode Island/epidemiology , Socioeconomic Factors
14.
Biochemistry ; 53(33): 5414-23, 2014 Aug 26.
Article in English | MEDLINE | ID: mdl-25020031

ABSTRACT

Most class A ß-lactamases cannot hydrolyze carbapenem antibiotics effectively. The molecular mechanism of this catalytic inefficiency has been attributed to the unique stereochemistry of carbapenems, including their 6-α-hydroxyethyl side chain and the transition between two tautomeric states when bound at the active site. Previous studies have shown that the 6-α-hydroxyethyl side chain of carbapenems can interfere with catalysis by forming hydrogen bonds with the deacylation water molecule to reduce its nucleophilicity. Here our studies of a class A noncarbapenemase PenP demonstrate that substituting the general base residue Glu166 with Ser or other residues leads to a significant enhancement of the acylation kinetics by ∼100-500 times toward carbapenems like meropenem. The structures of PenP and Glu166Ser both in apo form and in complex with meropenem reveal that Glu166 is critical for the formation of a hydrogen bonding network within the active site that locks Asn170 in an orientation to impose steric clash with the 6-α-hydroxyethyl side chain of meropenem. The Glu166Ser substitution weakens this network and enables Asn170 to adopt an alternative conformation to avoid steric clash and accommodate faster acylation kinetics. Furthermore, the weakened hydrogen bonding network caused by the Glu166Ser substitution allows the 6-α-hydroxyethyl moiety to adopt a catalytically favorable orientation as seen in class A carbapenemases. In summary, our data identify a previously unreported role of the universally conserved general base residue Glu166 in impeding the proper binding of carbapenems by restricting their 6-α-hydroxyethyl group.


Subject(s)
Carbapenems/metabolism , beta-Lactamases/chemistry , beta-Lactamases/metabolism , Acylation , Amino Acid Substitution , Bacillus/enzymology , Binding Sites , Catalytic Domain , Cephaloridine/chemistry , Crystallography, X-Ray , Glutamic Acid/chemistry , Kinetics , Meropenem , Models, Molecular , Protein Conformation , Thienamycins/metabolism , beta-Lactamases/genetics
15.
Food Chem X ; 22: 101432, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38764783

ABSTRACT

Aroma plays a pivotal role in the quality of black tea. However, the acceptability of black tea is greatly limited by the green off-flavor (GOF) resulting from the inappropriate processing control. In this study, the key odorants causing GOF were investigated by volatolomics, and their dynamic changes and formation pathways were in-depth understood. Significant alterations in volatile metabolites were observed in the withering stage. A total of 14 key odorants were identified as contributors to GOF, including 2-methylpropanal, 3-methylbutanal, 1-hexanol, nonanal, (E, E)-2,4-heptadienal, benzaldehyde, linalool, (E, E)-3,5-octadiene-2-one, ß-cyclocitral, phenylacetaldehyde, (E, E)-2,4-nonadienal, methyl salicylate, geraniol, and ß-ionone. Among them, (E, E)-2,4-heptadienal (OAV = 3913), characterized by fatty, green, and oily aromas, was considered to be the most important contributor causing GOF. Moreover, it was found that lipid degradation served as the primary metabolic pathway for GOF. This study provides a theoretical foundation for off-flavor control and quality improvement of black tea.

16.
Food Res Int ; 187: 114330, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38763633

ABSTRACT

Processing technology plays a crucial role in the formation of tea aroma. The dynamic variations in volatile metabolites across different processing stages of fresh scent green tea (FSGT) were meticulously tracked utilizing advanced analytical techniques such as GC-E-Nose, GC-MS, and GC × GC-TOFMS. A total of 244 volatile metabolites were identified by GC-MS and GC × GC-TOFMS, among which 37 volatile compounds were concurrently detected by both methods. Spreading and fixation stages were deemed as pivotal processes for shaping the volatile profiles in FSGT. Notably, linalool, heptanal, 2-pentylfuran, nonanal, ß-myrcene, hexanal, 2-heptanone, pentanal, 1-octen-3-ol, and 1-octanol were highlighted as primary contributors to the aroma profiles of FSGT by combining odor activity value assessment. Furthermore, lipid degradation and glycoside hydrolysis were the main pathways for aroma formation of FSGT. The results not only elucidate the intricate variations in volatile metabolites but also offer valuable insights into enhancing the processing techniques for improved aroma quality of green tea.


Subject(s)
Food Handling , Gas Chromatography-Mass Spectrometry , Odorants , Tea , Volatile Organic Compounds , Volatile Organic Compounds/analysis , Volatile Organic Compounds/metabolism , Gas Chromatography-Mass Spectrometry/methods , Odorants/analysis , Tea/chemistry , Food Handling/methods , Electronic Nose , Aldehydes/analysis , Aldehydes/metabolism , Acyclic Monoterpenes/metabolism , Acyclic Monoterpenes/analysis , Camellia sinensis/chemistry , Camellia sinensis/metabolism , Ketones/analysis , Ketones/metabolism , Octanols
17.
Food Chem ; 463(Pt 4): 141482, 2024 Oct 09.
Article in English | MEDLINE | ID: mdl-39388885

ABSTRACT

Spreading serves as a pivotal process in the flavor development of green tea. In this study, the effects of spreading under five light irradiation on the volatile and non-volatile metabolites of green tea were comprehensively investigated using intelligent sensory technologies integrated with targeted and non-targeted metabolomics analyses. The incorporation of yellow light irradiation into spreading process significantly improved the overall quality of green tea. A total of 71 volatile and 112 non-volatile metabolites were identified by GC-MS/MS and UHPLC-Q-Exactive/MS, respectively. Among them, 20 key odorants with OAVs exceeding 1 were screened out. Moreover, phenylethyl alcohol, ß-damascenone, ß-ionone, (E, Z)-2,6-nonadienal, linalool, and phenylacetaldehyde with higher OAVs were pivotal contributors to the aroma quality under different light irradiation. Additionally, 13 non-volatile metabolites with VIP > 1.2 were recognized as key differential metabolites under different light irradiation. The results provide technical support and theoretical guidance for enhancing the processing technology of green tea.

18.
Food Res Int ; 192: 114773, 2024 Sep.
Article in English | MEDLINE | ID: mdl-39147497

ABSTRACT

Withering is the first and key process that influences tea quality, with light quality being a key regulatory factor. However, effects of withering light quality (WLQ) on transformation and formation pathways of tea aroma and volatile metabolites (VMs) remain unclear. In the present study, four WLQs were set up to investigate their effects on tea aroma and VMs. The results showed that blue and red light reduced the grassy aroma and improved the floral and fruity aroma of tea. Based on GC-MS/MS, 83 VMs were detected. Through VIP, significant differences, and OAV analysis, 13 key differential VMs were screened to characterize the differential impacts of WLQ on tea aroma. Further analysis of the evolution and metabolic pathways revealed that glycoside metabolism was the key pathway regulating tea aroma through WLQ. Blue light withering significantly enhanced glycosides hydrolysis and amino acids deamination, which was beneficial for the enrichment of floral and fruity VMs, such as geraniol, citral, methyl salicylate, 2-methyl-butanal, and benzeneacetaldehyde, as well as the transformation of grassy VMs, such as octanal, naphthalene, and cis-3-hexenyl isovalerate, resulting in the formation of tea floral and fruity aroma. The results provide theoretical basis and technical support for the targeted processing of high-quality tea.


Subject(s)
Camellia sinensis , Gas Chromatography-Mass Spectrometry , Light , Metabolomics , Odorants , Tea , Volatile Organic Compounds , Volatile Organic Compounds/analysis , Volatile Organic Compounds/metabolism , Metabolomics/methods , Odorants/analysis , Tea/chemistry , Camellia sinensis/chemistry , Camellia sinensis/radiation effects , Camellia sinensis/metabolism , Glycosides/analysis , Glycosides/metabolism
19.
Food Res Int ; 178: 113876, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38309897

ABSTRACT

The species and contents of ɑ-dicarbonyls in commercial black tea were examined, along with the effects of the manufacturing process and drying temperature on the formation of ɑ-dicarbonyls. Ten ɑ-dicarbonyls were quantified in commercial and in-process black tea samples by using UPLC-MS/MS and their derived quinoxalines. The ɑ-dicarbonyls content in commercial black tea decreased significantly (p < 0.05) in the following order: 3-deoxyglucosone > glucosone > 3-deoxypentosone = threosone > galactosone ≥ methylglyoxal = glyoxal ≥ 3-deoxygalactosone = 3-deoxythreosone = diacetyl. Except for 3-deoxyglucosone and 3-deoxygalactosone, a further eight ɑ-dicarbonyls were identified in all manufacturing steps of black tea. Except for the drying step, the rolling and fermenting played important roles in the formation of ɑ-dicarbonyls. The total contents of ɑ-dicarbonyls in black tea infusion ranged from 16.48 to 75.32 µg/g based on our detected ten ɑ-dicarbonyls.


Subject(s)
Camellia sinensis , Tea , Maillard Reaction , Chromatography, Liquid , Tandem Mass Spectrometry , Glyoxal/analysis
20.
Foods ; 13(5)2024 Feb 28.
Article in English | MEDLINE | ID: mdl-38472841

ABSTRACT

Aroma is an indispensable factor that substantially impacts the quality assessment of black tea. This study aims to uncover the dynamic alterations in the sweet and floral aroma black tea (SFABT) throughout various manufacturing stages using a comprehensive analytical approach integrating gas chromatography electronic nose, gas chromatography-ion mobility spectrometry (GC-IMS), and gas chromatography-mass spectrometry (GC-MS). Notable alterations in volatile components were discerned during processing, predominantly during the rolling stage. A total of 59 typical volatile compounds were identified through GC-IMS, whereas 106 volatile components were recognized via GC-MS throughout the entire manufacturing process. Among them, 14 volatile compounds, such as linalool, ß-ionone, dimethyl sulfide, and 1-octen-3-ol, stood out as characteristic components responsible for SFABT with relative odor activity values exceeding one. This study serves as an invaluable theoretical platform for strategic controllable processing of superior-quality black tea.

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