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1.
J Sci Food Agric ; 2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-39099404

RESUMO

BACKGROUND: Roasting is an essential step in making roasted teas, and its role in producing flavors has been widely studied. However, the variation of potential hazardous compounds during the tea roasting process is still vague. The present study established an effective method based on liquid chromatography-triple quadrupole-tandem mass spectrometry to simultaneously determine the variation of acrylamide (AA), 5-hydroxymethylfurfural (5-HMF), and free amino acids during the tea roasting process. Meanwhile, the effects of several tea polyphenols on the formation of AA and 5-HMF were investigated by a wet-to-dry thermal model reaction. RESULTS: Medium-temperature roasted teas had the highest levels of AA and 5-HMF, with ranges of 0.13-0.15 µg g-1 and 68.72-123.98 µg g-1, respectively. Quantitative results showed that the levels of monosaccharides and amino acids decreased during roasting, which might contribute to the formation of 5-HMF and AA. Meanwhile, the decrease of epigallocatechin gallate (EGCG), epigallocatechin (EGC), and epicatechin (EC) might be related to their inhibitory effects on 5-HMF and AA. Thermal model reaction results showed that EGCG and EC significantly inhibited 5-HMF formation with a decline rate of 33.33% and 72.22%, respectively, mainly by trapping glucose. Gallic acid (GA) also had an inhibitory effect on the formation of AA (decreased by 92.86%) and 5-HMF (44.44%), mainly through impeding the preliminary reaction of asparagine and glucose. CONCLUSION: The roasting temperature determined the levels of AA and 5-HMF in teas. Catechins inhibited the formation of 5-HMF and AA mostly through trapping monosaccharides, while the inhibitory effect of GA was achieved by impeding the reaction. © 2024 Society of Chemical Industry.

2.
Food Res Int ; 191: 114740, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39059930

RESUMO

To explore the influence of tea trichomes on the quality of white tea, liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS), and headspace solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) were used to identify non-volatile and volatile compounds white tea without trichomes (WTwt) and pure trichomes (PT). It was found that the bitter and astringent compounds, caffeine (CAF), epigallocatechin gallate (EGCG), epicatechin gallate (ECG) and flavonol glycosides, were mainly enriched in the WTwt, with 16.3-fold, 47.1-fold and 28.7-fold decrease in CAF and EGCG and ECG, respectively, and the content of these compounds in PT were lower than the taste thresholds. In PT, kaempferol-3-O-(p-coumaroyl)-glucoside and kaempferol-3-O-(di-p-coumaroyl)-glucoside were non-volatile marker compounds, and decanal was significant aroma contributor with rOAV = 250.86. Moreover, the compounds in trichomes mainly contributed to the fruity and floral aroma of white tea, among which benzyl alcohol, (E)-geranylacetone, decanal, dodecanal and 6-methyl-5-hepten-2-one were the crucial aroma components, which were 2.1, 1.7, 1.8, 1.4 and 2.2 times as much as the WTwt in the PT, respectively. In conclusion, trichomes can improve the quality of white tea by reducing the bitterness and astringency, increasing the umami, as well as enhancing the fruity and floral aromas.


Assuntos
Camellia sinensis , Catequina , Cromatografia Gasosa-Espectrometria de Massas , Metabolômica , Paladar , Chá , Tricomas , Cromatografia Gasosa-Espectrometria de Massas/métodos , Chá/química , Metabolômica/métodos , Tricomas/química , Catequina/análise , Catequina/análogos & derivados , Camellia sinensis/química , Microextração em Fase Sólida , Humanos , Compostos Orgânicos Voláteis/análise , Cafeína/análise , Cromatografia Líquida/métodos , Odorantes/análise , Masculino , Adulto , Espectrometria de Massa com Cromatografia Líquida
3.
Food Res Int ; 190: 114638, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38945627

RESUMO

Tea trichomes were regarded as an essential evaluation index for reflecting tea flavor quality in terms of aroma and influence on infusion color. This study reveals the impact of golden oxidized trichomes on the color, volatile and non-volatile metabolites of black teas through comparative metabolomics combined quantitative analysis on hongbiluo (trichomes-deficiency black teas), hongjinluo (trichomes-rich black teas), and trichomes (from hongjinluo). Forty-six volatile components were detected using headspace solid-phase microextraction gas chromatography-mass spectrometry, while the results suggested that the contribution of trichomes to black teas is limited. A total of 60 marker non-volatile compounds were identified, including catechins, catechin oxidation products, flavonoid glycosides, organic acids, hydrolysable tannins and amino acids. Notably, p-coumaroyl-kaempferol glucosides, and catechin dimers demonstrated high levels in independent trichomes and showed a positive correlation with the brightness and yellow hue of black tea infusions, specifically kaempferol 3-O-di-(p-coumaroyl)-hexoside. Furthermore, results from fractional extraction analysis of separated trichomes provided that N-ethyl-2-pyrrolidinone-substituted epicatechin gallates, acylated kaempferol glycosides, and chromogenic catechins dimers, such as theaflavins, were primary color contributors in oxidized trichomes. Especially, we found that epicatechin gallate (ECG) and its derivates, 3'-O-methyl-ECG and N-ethyl-2-pyrrolidinone-substituted ECG, highly accumulated in trichomes, which may be associated with the varieties of hongbiluo and hongjinluo black teas. Eventually, addition tests were applied to verify the color contribution of trichome mixtures. Our findings employed comprehensive information revealing that golden oxidized trichomes contributed significantly to the brightness and yellow hue of black tea infusion, but their contribution to the aroma and metabolic profile is limited. These findings may contribute to the effective modulation of the infusion color during black tea production by regulating the proportion of tea trichomes or screening trichomes-rich or deficiency varieties.


Assuntos
Camellia sinensis , Cor , Cromatografia Gasosa-Espectrometria de Massas , Metabolômica , Oxirredução , Chá , Tricomas , Compostos Orgânicos Voláteis , Metabolômica/métodos , Chá/química , Camellia sinensis/química , Compostos Orgânicos Voláteis/análise , Tricomas/química , Tricomas/metabolismo , Catequina/análise , Catequina/análogos & derivados , Catequina/metabolismo , Microextração em Fase Sólida , Folhas de Planta/química , Metaboloma , Flavonoides/análise
4.
Foods ; 13(9)2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38731716

RESUMO

It is now widely recognized that gut microbiota plays a critical role not only in the development and progression of diseases, but also in its susceptibility to dietary patterns, food composition, and nutritional intake. In this comprehensive review, we have compiled the latest findings on the effects of food nutrients and bioactive compounds on the gut microbiota. The research indicates that certain components, such as unsaturated fatty acids, dietary fiber, and protein have a significant impact on the composition of bile salts and short-chain fatty acids through catabolic processes, thereby influencing the gut microbiota. Additionally, these compounds also have an effect on the ratio of Firmicutes to Bacteroides, as well as the abundance of specific species like Akkermansia muciniphila. The gut microbiota has been found to play a role in altering the absorption and metabolism of nutrients, bioactive compounds, and drugs, adding another layer of complexity to the interaction between food and gut microbiota, which often requires long-term adaptation to yield substantial outcomes. In conclusion, understanding the relationship between food compounds and gut microbiota can offer valuable insights into the potential therapeutic applications of food and dietary interventions in various diseases and health conditions.

5.
Food Res Int ; 184: 114266, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38609242

RESUMO

The capacity differences of seven catechin monomers to produce colors after treating with catechin-free extract were investigated. After 240-min reaction, only (-)-epicatechin (EC) and (+)-catechin (C) presented obvious luminous red color with L* values of 63.32-71.73, a* values of 37.13-46.44, and b* values of 65.64-69.99. Meanwhile, the decrease rate of EC and C was 43.52 %-50.35 %, which were significantly lower than those of other catechin monomers (85.91 %-100 %). The oxidized products of catechin monomers were analyzed by ultra-high performance liquid chromatography-quadrupole-time of flight-mass spectrometry coupled with diode array detector, wherein dehydro-dimers and -trimers (oxidative coupling products of catechins' A-B ring) were found to be the major chromogenic compounds of EC and C. Additionally, the antioxidant capacity of catechin monomers only decreased after 30-min reaction, while along with further enzymatic reaction, catechin monomers presented comparable oxyradical scavenging ability (e.g., the DPPH inhibitory rates of catechin monomers were in the range of 24.42 %-50.77 %) to vitamin C (positive control, DPPH inhibitory rate was 27.66 %). Meanwhile, the inhibitory effects of most catechin monomers on α-glucosidase were enhanced in different degrees. These results provided basis for the development of enzymatically-oxidized catechin monomers as functional food color additives.


Assuntos
Catequina , Colorimetria , Espectrometria de Massas , Espectrometria de Massa com Cromatografia Líquida , Antioxidantes
6.
Food Chem ; 446: 138827, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38402772

RESUMO

As the final processing step, drying temperature between 90 and 140 â„ƒ is usually applied to terminate enzymatic activities and improve sensory characteristics of black tea. Liquid chromatography tandem mass spectrometry (LC-MS) based non-targeted and targeted metabolomics analyses combined in vitro biological assays were adopted to investigate the chemical and biological variations after drying. Fifty-nine differentially expressed metabolites including several hydroxycinnamic acid derivatives and pyroglutamic acid-glucose Amadori rearrangement products (ARPs) were identified, the latter of which was correspondingly accumulated with increasing temperature. The levels of theaflavins (TFs), thearubigins (TRs), monosaccharides and free amino acids gradually decreased with increasing temperature. Furthermore, the bioassays of black tea showed that drying under 110 â„ƒ provided the highest antioxidant capacities, but the inhibitory effects on α-glucosidase and α-amylase were decreasing along with increasing drying temperature. These results are valuable for optimizing drying process to obtain superior sensory properties and preserve bioactivities of black tea.


Assuntos
Camellia sinensis , Chá , Chá/química , Polifenóis/análise , Temperatura , Camellia sinensis/química , Cromatografia Líquida , Antioxidantes/análise
7.
J Agric Food Chem ; 72(8): 4384-4392, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38354408

RESUMO

The linoleic acid reaction models were set at 150 °C for 120 min, and its oxidation process was monitored by nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS). Results showed that no furan was formed from linoleic acid without heating, while furan accumulated throughout the heating process. Linoleic acid ran out within 30 min, which indicated that furan was formed mainly from the intermediate oxidation products of linoleic acid after 30 min. It should be noticed that the content of (E,E)-2,4-decadienal reached maximum once the linoleic acid ran out and then decreased with the formation of furan. Multivariate statistical analysis suggested that (E,E)-2,4-decadienal was the most important aldehyde related to furan formation during linoleic acid oxidation. To prove this assumption, the variation of furan from (E,E)-2,4-decadienal reaction models heating at 150 °C for 60 min was also studied. Results showed that the content of furan increased with the oxidation of (E,E)-2,4-decadienal. Furthermore, NMR and GC-MS data proved that (E,E)-2,4-decadienal could be oxidized to 4,5-epoxy-(E)-2-decenal. In conclusion, our results supported (E,E)-2,4-decadienal and trans-4,5-epoxy-(E)-2-decenal as critical intermediate products of furan formation from linoleic acid oxidation.


Assuntos
Aldeídos , Alcenos , Temperatura Alta , Ácido Linoleico , Ácido Linoleico/química , Oxirredução , Furanos/química
8.
J Agric Food Chem ; 71(42): 15745-15753, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37816159

RESUMO

Not only do flavan-3-ols participate in the formation of chromogenic oxidation products such as theaflavins, but chlorogenic acid (3-caffeoylquinic acid, CQA) is also involved in the enzymatic oxidation during black tea processing. The critical oxidation product of CQA and (-)-epigallocatechin (EGC) were identified as an adduct containing benzobicyclo[3.2.2]nonenone structure, which was named as the dichlorogeniccatechin (DCGC) oligomer. It was composed of two molecules of CQA and one molecule of EGC. The effects of the initial reactant ratio and reaction time on the generation of DCGC were also analyzed. A high proportion of CQA promoted the production of DCGC, but a high proportion of EGC inhibited the DCGC formation. In addition, the content of DCGC in Keemun black tea during processing was determined. The content of DCGC highly increased after withering but decreased after drying. This study provides a new perspective for the investigation of other oxidation oligomers in black tea.


Assuntos
Camellia sinensis , Catequina , Chá/química , Ácido Clorogênico , Catequina/química , Camellia sinensis/química , Oxirredução
9.
Compr Rev Food Sci Food Saf ; 22(6): 4890-4924, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37786329

RESUMO

With the development of metabolomics analytical techniques, relevant studies have increased in recent decades. The procedures of metabolomics analysis mainly include sample preparation, data acquisition and pre-processing, multivariate statistical analysis, as well as maker compounds' identification. In the present review, we summarized the published articles of tea metabolomics regarding different analytical tools, such as mass spectrometry, nuclear magnetic resonance, ultraviolet-visible spectrometry, and Fourier transform infrared spectrometry. The metabolite variation of fresh tea leaves with different treatments, such as biotic/abiotic stress, horticultural measures, and nutritional supplies was reviewed. Furthermore, the changes of chemical composition of processed tea samples under different processing technologies were also profiled. Since the identification of critical or marker metabolites is a complicated task, we also discussed the procedure of metabolite identification to clarify the importance of omics data analysis. The present review provides a workflow diagram for tea metabolomics research and also the perspectives of related studies in the future.


Assuntos
Metabolômica , Folhas de Planta , Metabolômica/métodos , Espectrometria de Massas , Espectroscopia de Ressonância Magnética/métodos , Folhas de Planta/química , Chá/química
10.
Front Endocrinol (Lausanne) ; 14: 1054674, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37033234

RESUMO

Goals: To assess the efficacy and safety of Chinese Medicine Prescription "W-LHIT" in subjects with simple obesity, and to explore its potential mechanism of action. Methods: Thirty-seven patients aged 18 to 60 from Wei-En hospital (Weifang City, Shandong, China), participated in a double blinded, placebo-controlled study. Subjects were randomly divided into 2 groups, 18 in treatment and 19 in placebo group. The treatment group took the "W-LHIT" capsules for two months, while the control group received placebo capsules. Both groups accepted healthy lifestyle education materials. After a 2-month treatment, the placebo group transferred to open-label treatment after unblinding. Results: 72.22% participants in the treatment group lost more than 5% of their body weight, compared with 36.84% in the placebo group (p < 0.001). Body weight loss and body mass index reduction of the treatment group were also significantly higher than those of the placebo group (p < 0.05). These changes were accompanied by increased abundance of Akkermansia muciniphila and Enterococcus faecium, and decreased abundance of Proteobacteria in gut microbiota. Furthermore, the treatment group also showed improvement in obesity-related comorbidities such as hypertension and elevation of liver enzymes. No serious adverse reactions were found during the study period. Weight did not rebound at a follow-up visit 2 months after treatment. Conclusion: W-LHIT significantly improved body weight and comorbid conditions without obvious adverse reaction or rebound weight gain. These effects were associated with increased abundance of probiotics in gut microbiota. W-LHIT may have a potential for treating obesity in conjunction with healthy lifestyle modifications.


Assuntos
Microbioma Gastrointestinal , Humanos , Obesidade/complicações , Obesidade/tratamento farmacológico , Redução de Peso , Resultado do Tratamento , Estilo de Vida
11.
J Agric Food Chem ; 70(37): 11727-11737, 2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36084346

RESUMO

Amadori rearrangement products (ARPs) derived from the Maillard reaction between theanine and glucose (ARP 1), as well as pyroglutamic acid and glucose (ARP 2), were identified by liquid chromatograph tandem mass spectroscopy methods. The effects of initial reactant ratio, temperature, pH, and heating time on ARP generation were analyzed. The formation of both ARPs was most favored under 100 °C, while an alkaline environment slightly promoted the generation of ARP 1 and acidic conditions contributed more to ARP 2 formation. The decomposition of ARP 1 was suggested to be the predominant formation mechanism of ARP 2. Preparation, purification, and structure identification of ARP 1 were conducted, with its structure confirmed as 1-deoxy-1-l-theanino-d-fructose. The contents of ARP 1 in green, black, dark, white, yellow, and Oolong teas were quantitatively determined, of which black teas contained the highest levels of ARP 1, possibly due to the high glucose content and processing techniques.


Assuntos
Glucose , Ácido Pirrolidonocarboxílico , Frutose , Glucose/química , Glutamatos , Reação de Maillard , Chá
12.
Food Funct ; 13(11): 6139-6151, 2022 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-35579412

RESUMO

Tea cream is a kind of turbid substance commonly existing in tea infusion and tea beverage upon cooling. Herein, a comparative study was conducted on the supernatant and cream from black tea infusion in terms of antioxidant, anti-inflammatory and enzyme inhibitory activities, and chemical composition. Ultraviolet-visible (UV-vis) spectrometry and high-performance liquid chromatography (HPLC) analysis showed that the contents of protein, polyphenols, theaflavins, thearubigins, theabrownins, and caffeine in cream were significantly higher than those in the supernatant. The contents of Al, Ca, Cu, and Fe elements in cream were higher than those in the supernatant. However, higher levels of monosaccharides and free amino acids were detected in the supernatant compared with cream. The ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) based metabolomics analysis revealed that the main marker compounds between the supernatant and the cream were organic acids, phenolic acids, and flavan-3-ols and their oxidation products, flavonol glycosides and amino acids. The cream showed better antioxidant and anti-inflammatory, as well as α-amylase and α-glycosidase inhibitory activities than the supernatant, because it contained higher contents of polyphenols than the supernatant. The present study expanded the new vision towards the cream of black tea infusion.


Assuntos
Camellia sinensis , Chá , Aminoácidos , Anti-Inflamatórios/análise , Anti-Inflamatórios/farmacologia , Antioxidantes/análise , Antioxidantes/farmacologia , Camellia sinensis/química , Cromatografia Líquida de Alta Pressão/métodos , Flavonoides/química , Polifenóis/química , Chá/química , alfa-Amilases
13.
Food Res Int ; 155: 111041, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35400430

RESUMO

Phenolic acids, including benzoic acid and hydroxycinnamic acid derivatives, are the main compounds of black tea. An efficient and accurate analytical method to quantify ten phenolic acids was established and validated by ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-QQQ-MS/MS). The chemical shifts during the processing of Keemun black tea were analyzed and the phenolic acids were quantified. Compared with fresh tea leaves, after processing, the contents of free phenolic acids, including gallic acid, salicylic acid, p-coumaric acid, and ferulic acid, increased markedly. Still, the contents of soluble conjugated phenolic acids, including p-coumaroylquinic acid isomers and chlorogenic acid isomers, decreased. Furthermore, the total contents of lignin, and insoluble bonded phenolic acids decreased. The adduct of (-)-epigallocatechin gallate and 3-caffeoylquinic acid was detected in tea samples, and its content increased highly after fermentation. The developed and validated analytical method can be used to monitor the manufacturing process of black tea.


Assuntos
Camellia sinensis , Chá , Camellia sinensis/química , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida , Espectrometria de Massas em Tandem/métodos , Chá/química
14.
J Agric Food Chem ; 70(18): 5715-5727, 2022 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-35475606

RESUMO

During the enzymatic oxidation of black tea, flavan-3-ols undergo a complicated chemical transformation and generate theaflavins and thearubigins. So far, the oxidation mechanism of flavan-3-ols has not been clarified. Liquid chromatography-tandem mass spectrometry-based metabolomics combined with o-quinone intermediates captured by o-phenylenediamine was developed and successfully applied in the liquid incubation of fresh tea homogenates. During the oxidation, the contents of catechins continuously decreased, while theaflavins increased first but decreased subsequently at the end of incubation. Meanwhile, the content of thearubigins greatly increased at the late stage of incubation. Dehydrotheasinensins were accumulated at the end of oxidation along with the decrease of theasinensins. Through o-phenylenediamine derivation, several adducts of (-)-epigallocatechin gallate, (-)-epigallocatechin, theasinensins A, B, C, and D, and corresponding dehydrotheasinensins were identified, which were considered as the substrates of thearubigins. These results suggested that theaflavins and these oxidation products contributed to the formation of thearubigins.


Assuntos
Catequina , Antioxidantes , Catequina/química , Cromatografia Líquida , Flavonoides/química , Espectrometria de Massas/métodos , Metabolômica , Fenilenodiaminas , Polifenóis/química , Quinonas , Chá/química
15.
Food Chem ; 386: 132788, 2022 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-35344723

RESUMO

Nine black tea samples with different color intensity were firstly determined by chromatic difference analyzer. The color characteristics were secondly quantitatively described by UV-visible spectroscopy. Thirdly, liquid chromatography tandem mass spectrometry (LC-MS) based metabolomics analysis was applied in low-molecular-weight compounds. Finally, the color contributors were identified by the correlation analysis of color, spectrometry and mass data. UV-visible based metabolomics analysis revealed that the wavelength at 380-520 nm (VIP > 1.50) was the critical absorbance band for distinguishing different color of BT infusions, while LC-MS based metabolomics analysis indicated that there were 48 main marker compounds responsible for the classification of different BT infusions. Correlation analysis results showed that the coefficients of theaflavins, thearubigins, theabrownins, flavonoid glycosides, and some hydroxycinnamoyl acids were > 0.7, which suggested they were main color contributors of BT infusion. The present study expanded a new vision on the color analysis of BT infusion.


Assuntos
Camellia sinensis , Chá , Camellia sinensis/química , Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Massas , Metabolômica/métodos , Espectrofotometria Ultravioleta , Chá/química
16.
J Agric Food Chem ; 70(12): 3832-3841, 2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-35289174

RESUMO

N-ethyl-2-pyrrolidinone-substituted flavan-3-ols (EPSFs) were prepared by an in vitro model reaction, and the taste thresholds of EPSFs and their dose-over-threshold factors in large-leaf yellow tea (LYT) were investigated. The effects of initial reactant ratios, reaction temperatures and time, pH values, and water addition on the yield of EPSFs were explored. The contents of EPSFs during roasting were determined by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS). When the initial ratio of (-)-epigallocatechin gallate (EGCG) to theanine was 1:2 and roasted under 120 °C for 120 min, the contents of EPSFs were the highest. The bitterness and astringency thresholds of four EPSF isomers were measured by the half-tongue method, of which EPSF2 and EPSF3 had higher thresholds than EGCG. In LYT, four EPSFs had lower bitterness and astringency dose-over-threshold factors than EGCG. This study suggested that the reduction of bitterness and astringency of tea after roasting may be mainly due to the formation of EPSFs.


Assuntos
Camellia sinensis , Camellia sinensis/química , Flavonoides/química , Pirrolidinonas , Paladar , Chá/química
17.
Front Nutr ; 9: 825381, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35284442

RESUMO

The peel of Citrus reticulata "Chachi" (CP) possesses various health-promoting benefits and is not only one of the most famous Chinese herbal medicine, but also an ingredient in fermented foods. In the present study, the effects of storage years (1-, 3-, 4-, 5-, 6-, and 11-years) on the chemical profiling and potential bioactive compounds of CP were compared by metabolomics and in vitro bioactivity analysis. With the increase of storage time, the content of hesperidin significantly decreased, but nobiletin, 3,5,6,7,8,3',4'-heptamethoxyflavone, and tangeretin were increased. Meanwhile, the antioxidant activity of CP was enhanced. Phenolic acids, flavonol glycosides, fatty acids, and alkyl glycosides were marker compounds that were responsible for distinguishing the storage time of CP. Correlation analysis suggested that some polyphenols including quercetin-glucoside, quinic acid, trihydroxydimethoxyflavone, and rutin were potential antioxidant compounds in CP. The dichloromethane and n-butanol fractions showed the better antioxidant capacity and inhibitory effects on glucose-hydrolysis enzymes. They mainly contained ferulic acid, nobiletin, 3,5,6,7,8,3',4'-heptamethoxyflavone, kaempferol, and hesperidin.

18.
Food Chem ; 381: 132284, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35121317

RESUMO

This study aimed to characterise pressurised hot water (PHW) extracts from nonconventional sources of functional carbohydrates and phenolic compounds in terms of antioxidant capacity, antiviral activity, toxicity, and human erythrocytes' protection antidiabetic potential. PHW extracts of Norway spruce bark (E1 + E2) and Birch sawdust (E3 + E4) contained mostly galactoglucomannan and glucuronoxylan. In contrast, samples E5 to E9 PHW extracted from Norway spruce, and Scots pine bark are rich sources of phenolic compounds. Overall, phenolic-rich extracts presented the highest inhibition of α-amylase and α-glucosidase and protection against stable non-enveloped enteroviruses. Additionally, all extracts protected human erythrocytes from hemolysis. Cell-based experiments using human cell lines (IMR90 and A549) showed extracts' non-toxicin vitroprofile. Considering the relative toxicological safety of extracts from these unconventional sources, functional carbohydrates and polyphenol-rich extracts can be obtained and further used in food models.


Assuntos
Ingredientes de Alimentos , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Florestas , Humanos , Mananas , Extratos Vegetais/farmacologia , Polissacarídeos , Xilanos
19.
Food Chem ; 374: 131796, 2022 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-34906807

RESUMO

Six grades of Huangshan Maofeng (HSMF) green tea were studied by LC-MS based metabolomics combined with sensory evaluation on bitterness, astringency and sweet aftertaste. Although there was no significant correlation (p > 0.05) between tea grades and the contents of total polyphenols and flavonoids, non-targeted metabolomics revealed that all grades of tea could be classified into two groups, group 1 (T1, T2) and group 2 (T3, 1, 2, 3). The main marker compounds responsible for distinguishing the two groups were procyanidins, flavonoid glycosides, and four hydrolysable tannins, including monogalloyl glucose, digalloyl glucose, trigalloyl glucose and galloyl-hexahydroxydiphenoyl-glucose. The Pearson correlation coefficients of these hydrolysable tannins with HSMF green tea grades were between 0.82 and 0.95. Furthermore, their Pearson correlation coefficients regarding sweet aftertaste were in the range of 0.73-0.83. This study suggested combination of metabolomics and sensory evaluation could provide an insight in searching for more potential taste-active components.


Assuntos
Espectrometria de Massas em Tandem , Chá , Cromatografia Líquida , Metabolômica , Polifenóis/análise
20.
Food Chem Toxicol ; 159: 112668, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34774677

RESUMO

A statistical optimization study was used to maximize the extraction of bioactive compounds and antioxidant activity from green tea derived from purple leaves of Camellia sinensis var. assamica. Simultaneous optimization was applied, and a combination of 60 °C, 15 min, and a mass-solvent ratio of 1 g of dehydrated purple leaves to 62.3 mL of an ethanol/citric acid solution, were determined as the ideal extraction conditions. The optimized extract of purple tea leaves (OEPL) contained showed stability in relation to variations in pH, and lyophilized OEPL exerted cytotoxic and antiproliferative effects against cancerous cells (A549 and HCT8), demonstrated antimicrobial activity towards Listeria monocytogenes (ATCC 7644), Staphylococcus aureus (ATCC 13565) and Staphylococcus epidermidis (ATCC 12288), inhibition of α-amylase and α-glycosidase enzymes and reduced the release of pro-inflammatory cytokines (TNF-α, CXCL2/MIP-2, and IL-6) in lipopolysaccharides-stimulated RAW 264.7 macrophages. Thus, our results provide a broad assessment of the bioactivity of "green" extracts obtained by a simple and low-cost process using non-toxic solvents, and they have the potential to be used for technological applications.


Assuntos
Antioxidantes , Camellia sinensis/química , Extratos Vegetais , Células A549 , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Bactérias/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Citocinas/metabolismo , Humanos , Fenóis/química , Fenóis/farmacologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Folhas de Planta/química , Espécies Reativas de Oxigênio/metabolismo
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