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1.
Food Microbiol ; 111: 104206, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36681402

RESUMO

The conversion of phenolic compounds by lactobacilli in food fermentations contributes to food quality. The metabolism of phenolics by lactobacilli has been elucidated in the past years but information on the contribution of specific enzymes in food fermentations remains scarce. This study aimed to address this gap by disruption of genes coding for the hydroxycimmanic acid reductase Par1, the hydroxycinnamic acid decarboxylase Pad, the hydrocinnamic esterase EstR, and strains with disruption of all three genes in Furfurilactobacillus milii FUA3583. The conversion of phenolics by Ff. milii and its isogenic mutants in sorghum fermentations was studied by LC-UV and LC-UV-MS/MS analyses. Ff. milii FUA3583 converted hydroxycinnamic acids predominantly with Par1. Vinylphenols were detected only in mutants lacking par1. A phenotype for the estR defective mutant was not identified. The formation of pyrano-3-deoxyanthocyanidins was observed only after fermentation with strains expressing Pad. Specifically, formation of these compounds was low with Ff. milii FUA3583, substantially increased in the Par1 mutant and abolished in all mutants with disrupted pad. Competition experiments with Ff. milii FUA3583 and its isogenic mutants demonstrated that expression of one of the two metabolic pathways for hydroxycinnamic acids increases the ecological fitness of the strain. Disruption of EstR in a Δpar1Δpar2Δpad background improved ecological fitness, indirectly demonstrating a phenotype of the esterase in Ff. milii. The documentation of the functionality of genes coding for conversion of hydroxycinnamic acids may support the selection of starter cultures for improved quality of fermented cereal products.


Assuntos
Ácidos Cumáricos , Sorghum , Ácidos Cumáricos/metabolismo , Grão Comestível/metabolismo , Fermentação , Lactobacillus/metabolismo , Fenóis/metabolismo , Espectrometria de Massas em Tandem
2.
Molecules ; 26(5)2021 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-33802304

RESUMO

The approach presented in this study is the first for the hemisynthesis of methylated anthocyanins. It was possible to obtain cyanidin-3-O-glucoside derivatives with different degrees of methylation. Cautious identification of 4'-, 5-, and 7-OH monomethylated derivatives was also accomplished. The methylation agent used was the "green chemical" dimethyl carbonate (DMC), which is characterized by low human and ecological toxicity. The influence of the temperature, reaction time, and amount of the required diazabicyclo[5.4.0]undec-7-en (DBU) catalyst on the formation of the products was examined. Compared to conventional synthesis methods for methylated flavonoids using DMC and DBU, the conditions identified in this study result in a reduction of reaction time, and an important side reaction, so-called carboxymethylation, was minimized by using higher amounts of catalyst.


Assuntos
Antocianinas/química , Formiatos/química , Metilação , Estrutura Molecular
3.
Molecules ; 26(9)2021 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-34064428

RESUMO

Berry pomace, rich in polyphenols, especially anthocyanins, accumulates during the production of red juices. Pomace from chokeberry (Aronia melanocarpa Michx.), bilberry (Vaccinium myrtillus L.), and elderberry (Sambucus nigra L.) represent good sources of coloring foodstuffs. Pomace powders (PP) were prepared by milling the seedless fractions of the three dried berry pomaces (50 °C, 8 h). Techno-functional properties of the powders such as particle size distribution, bulk density, sedimentation velocity, and swelling capacity were determined to evaluate the powders for possible food applications. Total anthocyanin content was quantified by UHPLC-DAD before and during a storage experiment to monitor the degradation of anthocyanins in the PP and in a yogurt model application. The high content of phenolic compounds and the still intact cell structure ensured high stability of anthocyanins over 28 days of storage. In the model application, color saturation was stable over the whole storage time of 14 days. Regarding the techno-functional properties, only a few differences between the three PP were observed. The particle size of elderberry PP was larger, resulting in lowest bulk density (0.45 g/mL), high cold-water solubility (16.42%), and a swelling capacity of 10.16 mL/g dw. Sedimentation velocity of the three PP was fast (0.02 mL/min) due to cluster formation of the particles caused by electrostatic and hydrophobic properties. Compared to other high-intensity coloring foodstuffs, the use of PP, showing acceptable color stability with potential health-promoting effects, represents a wide applicability in different food applications and especially in products with a longer shelf-life.


Assuntos
Corantes de Alimentos/química , Photinia/química , Sambucus/química , Vaccinium myrtillus/química , Antocianinas/análise , Cor , Umidade , Óleos/química , Tamanho da Partícula , Fenóis/análise , Pós , Água/química , Iogurte/análise
4.
Molecules ; 26(8)2021 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-33917913

RESUMO

The metabolism of anthocyanins in humans is still not fully understood, which is partly due to the lack of reference compounds. It is known that sulfation is one way of the complex phase II biotransformation mechanism. Therefore, cyanidin-3-O-glucoside and the cyanidin aglycone were chemically converted to their sulfates by reaction with sulfur trioxide-N-triethylamine complex in dimethylformamide. The reaction products were characterized by UHPLC coupled to linear ion trap and IMS-QTOF mass spectrometry. Based on MS data, retention times, and UV-Vis spectra, the compounds could tentatively be assigned to A-, C-, or B-ring sulfates. Analysis of urine samples from two volunteers after ingestion of commercial blackberry nectar demonstrated the presence of two sulfated derivatives of the cyanidin aglycone and one sulfated derivative of the cyanidin-3-O-glucoside. It was found that both the A ring and the B ring are sulfated by human enzymes. This study marks an important step toward a better understanding of anthocyanin metabolism.


Assuntos
Antocianinas/síntese química , Metaboloma , Sulfatos/síntese química , Antocianinas/química , Antocianinas/urina , Humanos , Projetos Piloto , Espectrometria de Massas por Ionização por Electrospray , Espectrofotometria Ultravioleta , Sulfatos/química , Sulfatos/urina , Fatores de Tempo
5.
Int J Syst Evol Microbiol ; 70(5): 3027-3036, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32223834

RESUMO

A pink-coloured bacterium (strain KR32T) was isolated from cheese and assigned to the 'Arthrobacter agilis group'. Members of the 'pink Arthrobacter agilis group' form a stable clade (100 % bootstrap value) and contain the species Arthrobacter agilis, Arthrobacter ruber and Arthrobacter echini, which share ≥99.0 % 16S rRNA gene sequence similarity. Isolate KR32T showed highest 16S rRNA gene sequence similarity (99.9 %) to A. agilis DSM 20550T. Additional multilocus sequence comparison confirmed the assignment of strain KR32T to the clade 'pink A. agilis group'. Average nucleotide identity and digital DNA-DNA hybridization values between isolate KR32T and A. agilis DSM 20550T were 82.85 and 26.30 %, respectively. The G+C content of the genomic DNA of isolate KR32T was 69.14 mol%. Chemotaxonomic analysis determined anteiso-C15 : 0 as the predominant fatty acid and MK-9(H2) as the predominant menaquinone. Polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and monoacyldimannosyl-monoacylglycerol. The peptidoglycan type of the isolate was A3α. The carotenoid bacterioruberin was detected as the major pigment. At 10 °C, strain KR32T grew with increased concentrations of bacterioruberin and production of unsaturated fatty acids. Strain KR32T was a Gram-stain-positive, catalase-positive, oxidase-positive and coccus-shaped bacterium with optimal growth at 27-30 °C and pH 8. The results of phylogenetic and phenotypic analyses enabled the differentiation of the isolate from other closely related species of the 'pink A. agilis group'. Therefore, strain KR32T represents a novel species for which the name Arthrobacter bussei sp. nov. is proposed. The type strain is KR32T (=DSM 109896T=LMG 31480T=NCCB 100733T).


Assuntos
Arthrobacter/classificação , Queijo/microbiologia , Microbiologia de Alimentos , Filogenia , Animais , Arthrobacter/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , Bovinos , Parede Celular/química , DNA Bacteriano/genética , Ácidos Graxos/química , Feminino , Alemanha , Glicolipídeos/química , Leite , Hibridização de Ácido Nucleico , Peptidoglicano/química , Fosfolipídeos/química , Pigmentação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
6.
Int J Mol Sci ; 21(7)2020 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-32230810

RESUMO

Mineralization of hydrogel biomaterials with calcium phosphate (CaP) is considered advantageous for bone regeneration. Mineralization can be both induced by the enzyme alkaline phosphatase (ALP) and promoted by calcium-binding biomolecules, such as plant-derived polyphenols. In this study, ALP-loaded gellan gum (GG) hydrogels were enriched with gallotannins, a subclass of polyphenols. Five preparations were compared, namely three tannic acids of differing molecular weight (MW), pentagalloyl glucose (PGG), and a gallotannin-rich extract from mango kernel (Mangifera indica L.). Certain gallotannin preparations promoted mineralization to a greater degree than others. The various gallotannin preparations bound differently to ALP and influenced the size of aggregates of ALP, which may be related to ability to promote mineralization. Human osteoblast-like Saos-2 cells grew in eluate from mineralized hydrogels. Gallotannin incorporation impeded cell growth on hydrogels and did not impart antibacterial activity. In conclusion, gallotannin incorporation aided mineralization but reduced cytocompatibility.


Assuntos
Biomimética/métodos , Hidrogéis/química , Taninos Hidrolisáveis/metabolismo , Plantas/metabolismo , Polissacarídeos/química , Fosfatase Alcalina/metabolismo , Antibacterianos/farmacologia , Materiais Biocompatíveis , Regeneração Óssea , Calcificação Fisiológica/efeitos dos fármacos , Fosfatos de Cálcio , Humanos , Taninos Hidrolisáveis/farmacologia , Mangifera/química , Minerais/química , Osteoblastos/metabolismo , Extratos Vegetais/química , Polifenóis/química , Polissacarídeos Bacterianos
7.
Molecules ; 25(19)2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-33023270

RESUMO

Volatile phenols like phenylpropanoid and benzoid compounds originate from the aromatic amino acid phenylalanine, which is biosynthesized via the shikimate/arogenate pathway. These volatile compounds contribute to the aroma of a number of economically important plant-derived foods like herbs, spices and fruits. The sequestration of numerous phenylpropanoid and benzoid compounds as glycosides occurs widely in fruits, and this pool represents an important source of flavor that can be released during storage and processing. Therefore, this review will provide an overview of the biosynthesis of free and glycosylated phenylpropanoid and benzoid compounds and their reactions during food processing, which both lead to the generation of odor-active volatile phenols in plant-derived foods.


Assuntos
Alimentos , Odorantes/análise , Fenóis/análise , Plantas Comestíveis/química , Compostos Orgânicos Voláteis/análise , Fenóis/química , Relação Estrutura-Atividade
8.
Molecules ; 25(3)2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-31991680

RESUMO

Recent in vitro and in vivo studies on anthocyanins confirmed numerous health-promoting effects in humans. Daily anthocyanin intake can be estimated via food databases, but the amount absorbed by the organism still remains uncertain because anthocyanin bioavailability is yet to be elucidated in its entirety. For this purpose, suitable and validated methods of sample preparation and analysis are required. Therefore, a sample preparation method for anthocyanin metabolite analysis in plasma was successfully established and validated. The validation yielded acceptable results for the anthocyanins in terms of recovery (54-108%) and precision (coefficient of variation (CV) < 15%). The UHPLC-MS method used in the consecutive reaction monitoring (CRM) mode was sufficiently sensitive, resulting in limits of detection <2.3 ng/mL and limits of quantification < 8.1 ng/mL with associated repeatability of the MS system with CVs of <5.1%. In addition, a method for the sum parameter determination of anthocyanidins in urine comprising solely the evaporation of acidified samples was developed, validated, and successfully applied to real samples. The results showed that this method is applicable for the methylated anthocyanidins, but not for the hydroxylated anthocyanidins, due to the chosen CRM modes required for optimum selectivity.


Assuntos
Antocianinas/sangue , Antocianinas/urina , Feminino , Humanos , Masculino
9.
J Sep Sci ; 39(16): 3113-22, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27418182

RESUMO

Fast methods for the extraction and analysis of various secondary metabolites from cocoa products were developed and optimized regarding speed and separation efficiency. Extraction by pressurized liquid extraction is automated and the extracts are analyzed by rapid reversed-phase ultra high-performance liquid chromatography and normal-phase high-performance liquid chromatography methods. After extraction, no further sample treatment is required before chromatographic analysis. The analytes comprise monomeric and oligomeric flavanols, flavonols, methylxanthins, N-phenylpropenoyl amino acids, and phenolic acids. Polyphenols and N-phenylpropenoyl amino acids are separated in a single run of 33 min, procyanidins are analyzed by normal-phase high-performance liquid chromatography within 16 min, and methylxanthins require only 6 min total run time. A fourth method is suitable for phenolic acids, but only protocatechuic acid was found in relevant quantities. The optimized methods were validated and applied to 27 dark chocolates, one milk chocolate, two cocoa powders and two food supplements based on cocoa extract.


Assuntos
Cacau/química , Fracionamento Químico/métodos , Extratos Vegetais/análise , Extratos Vegetais/isolamento & purificação , Polifenóis/química , Polifenóis/isolamento & purificação , Cacau/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Extratos Vegetais/metabolismo , Metabolismo Secundário
10.
Molecules ; 21(1): 91, 2016 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-26784152

RESUMO

Sunflower extraction meal (SEM) is an economically interesting protein source. During alkaline extraction of proteins, the presence of chlorogenic acid (CQA) in the meal gives rise to the formation of o-quinones. Reactions with nucleophiles present in proteins can lead to green discoloration. Although such reactions have been known for a long time, there is a lack of information on the chemical nature of the reaction products. SEM and model systems consisting of amino acids and CQA were subjected to alkaline treatment and, for comparison, to oxidation of CQA by polyphenoloxidase (PPO). Several green trihydroxy benzacridine (TBA) derivatives were tentatively identified in all samples by UHPLC-DAD-MS/MS. Surprisingly, in alkaline-treated samples of particular amino acids as well as in SEM, the same six TBA isomers were detected. In contrast, the enzymatically oxidized samples resulted in only three TBA derivatives. Contrary to previous findings, neither peptide nor amino acid residues were attached to the resultant benzacridine core. The results indicate that the formation of TBA derivatives is caused by the reaction between CQA quinones and free NH2 groups. Further research is necessary to elucidate the structure of the addition products for a comprehensive evaluation of food and feed safety aspects.


Assuntos
Acridinas/química , Álcalis/química , Ácido Clorogênico/química , Helianthus/química , Quinonas/química , Aminoácidos/química , Biomassa , Catecol Oxidase/química , Concentração de Íons de Hidrogênio , Oxirredução
11.
Anal Bioanal Chem ; 407(25): 7657-66, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26229030

RESUMO

Seeds of milk thistle, Silybum marianum (L.) Gaertn., are used for treatment and prevention of liver disorders and were identified as a high priority ingredient requiring a validated analytical method. An AOAC International expert panel reviewed existing methods and made recommendations concerning method optimization prior to validation. A series of extraction and separation studies were undertaken on the selected method for determining flavonolignans from milk thistle seeds and finished products to address the review panel recommendations. Once optimized, a single-laboratory validation study was conducted. The method was assessed for repeatability, accuracy, selectivity, LOD, LOQ, analyte stability, and linearity. Flavonolignan content ranged from 1.40 to 52.86% in raw materials and dry finished products and ranged from 36.16 to 1570.7 µg/mL in liquid tinctures. Repeatability for the individual flavonolignans in raw materials and finished products ranged from 1.03 to 9.88% RSDr, with HorRat values between 0.21 and 1.55. Calibration curves for all flavonolignan concentrations had correlation coefficients of >99.8%. The LODs for the flavonolignans ranged from 0.20 to 0.48 µg/mL at 288 nm. Based on the results of this single-laboratory validation, this method is suitable for the quantitation of the six major flavonolignans in milk thistle raw materials and finished products, as well as multicomponent products containing dandelion, schizandra berry, and artichoke extracts. It is recommended that this method be adopted as First Action Official Method status by AOAC International.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Flavonolignanos/análise , Sementes/química , Silybum marianum/química , Suplementos Nutricionais/análise , Limite de Detecção , Raios Ultravioleta
12.
J Sep Sci ; 38(24): 4166-72, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26467976

RESUMO

A fast isocratic liquid chromatography method was developed for the simultaneous quantification of eight xanthophylls (13-Z-lutein, 13'-Z-lutein, 13-Z-zeaxanthin, all-E-lutein, all-E-zeaxanthin, all-E-canthaxanthin, all-E-ß-apo-8'-carotenoic acid ethyl ester and all-E-ß-apo-8'-carotenal) within 12 min, compared to 90 min by the conventional high-performance liquid chromatography method. The separation was achieved on a YMC C30 reversed-phase column (100 mm x 2.0 mm; 3 µm) operated at 20°C using a methanol/tert-butyl methyl ether/water solvent system at a flow rate of 0.8 mL/min. The method was successfully applied to quantify lutein and zeaxanthin stereoisomers in egg yolk, raw and cooked spinach, and a dietary supplement. The method can be used for the rapid analysis of xanthophyll isomers in different food products and for quality control purposes.


Assuntos
Cromatografia Líquida , Análise de Alimentos/métodos , Xantofilas/análise , Xantofilas/química , Suplementos Nutricionais/análise , Gema de Ovo/química , Spinacia oleracea/química , Estereoisomerismo , Fatores de Tempo
13.
Foods ; 13(5)2024 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-38472799

RESUMO

Due to a widespread consumer reluctance toward synthetic food dyes, the interest in natural compounds from plants has increased. This study aimed to optimize the oxidation process between chlorogenic acid (CQA) and tryptophan (Trp) using sodium periodate (NaIO4) to obtain a red-colored pigment. The impact of temperature and different ratios of Trp to NaIO4 on the reaction progress was investigated. After the best conditions for the reaction were established, three pH values were tested. The reaction time could be reduced from 72 to 24 h with a yield of 46 ± 2% w/w based on the quantity of CQA. After the first purification step of the product by size exclusion chromatography, the pigment obtained was characterized for its solubility, and its hydrolyzed form was used for investigations into the stability at different pH values, storage under light and in the dark (period of 28 days), in the presence of reducing agents, and for heat resistance. Finally, several food matrices were successfully colored with the natural pigment in amounts from 0.005 to 0.01% (w/w). In conclusion, the present study provides new insights into the feasible production and comprehensive characterization of a red pigment derived from oxidative coupling of CQA and Trp, as well as its application in food systems.

14.
Food Res Int ; 188: 114442, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38823830

RESUMO

The long-term stability of red wine color depends on the formation of polymeric pigments from anthocyanins. Although there is still a lot of uncertainty about the specific structure of this diverse group of pigments, there is consensus that they are reaction products of anthocyanins and other polyphenols. Interactions between anthocyanins and pectic polysaccharides have been suggested to stabilize anthocyanins. This study explores the impact of such interactions by adding pectin during red winemaking. The results demonstrate that these interactions induce the formation of additional polymeric pigments which enhance the pigment stability during fermentation and aging. While initial pigment formation is higher in wines with added pectin, a notable proportion of the complexes degrades in the later stages of fermentation. Presumably, tannins form insoluble complexes with pectin, reducing tannin concentration by more than 300 mg/L. Anthocyanin concentrations decrease by over 400 mg/L, and polymeric pigments double. Anthocyanins that form polymeric pigments with pectic polysaccharides expand the range of pigments in red wines with possible consequences for the sensory properties of the wine. These findings highlight the complex interactions between pectin, anthocyanins, and tannins, and their influence on pigment formation and wine composition during fermentation and aging.


Assuntos
Antocianinas , Fermentação , Pectinas , Taninos , Vinho , Antocianinas/química , Antocianinas/análise , Pectinas/química , Vinho/análise , Taninos/química , Cor , Manipulação de Alimentos/métodos , Pigmentos Biológicos/química , Polímeros/química
15.
Phytochem Anal ; 24(2): 129-34, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22811209

RESUMO

INTRODUCTION: Rhodiola rosea L. is a medicinal herb used for its adaptogenic properties. The main active components are the phenylpropanoids collectively referred to as rosavins. OBJECTIVES: To develop an isolation method for phytochemicals present in Rhodiola rosea roots using high-speed counter-current chromatography (HSCCC). METHODOLOGY: The roots of Rhodiola rosea were extracted with methanol and fractionated using liquid-liquid partition and polyamide column clean-up. The purified fraction (100 mg) was subjected to semi-preparative HSCCC using the two-phase solvent system ethyl acetate:butanol:water (3:2:5). The head-to-tail elution mode was employed with a flow rate of 1.5 mL/min and a rotary speed of 1000 rpm. RESULTS: The separation yielded six main fractions with four components more than 90% pure. The sixth fraction was further purified using semi-preparative HPLC with a Synergi-hydro RP C18 -column to obtain rosin and geranyl 1-O-α-l-arabinopyranosyl(1 → 6)-ß-d-glucopyranoside. The main components isolated were rosavin (3.4 mg, 97% purity), salidroside (0.5 mg, 90% purity), benzyl-O-ß-d-glucopyranoside (1.2 mg, 85% purity), rosarin (1.3 mg, 99% purity), rosiridin (1.8 mg, 92% purity), rosin (1.2 mg, 95% purity) and geranyl 1-O-α-l-arabinopyranosyl(1 → 6)-ß-d-glucopyranoside (6.5 mg, 97% purity). The identity and purity of these components were confirmed using ultrafast liquid chromatography-diode-array detector-MS/MS analysis, ¹H- and ¹³C-NMR spectroscopy. CONCLUSION: High-speed counter-current chromatography was successful in the isolation of several phytochemicals present in Rhodiola rosea roots, including two components that are not commercially available.


Assuntos
Distribuição Contracorrente/métodos , Dissacarídeos/isolamento & purificação , Glicosídeos/isolamento & purificação , Monoterpenos/isolamento & purificação , Raízes de Plantas/química , Rhodiola/química , Cromatografia Líquida de Alta Pressão , Dissacarídeos/química , Glicosídeos/química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular , Monoterpenos/química , Plantas Medicinais/química , Reprodutibilidade dos Testes
16.
Plants (Basel) ; 12(12)2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37375868

RESUMO

High-performance counter-current chromatography (HPCCC) was used as a tool for the isolation and fractionation of phenolic compounds (PCs) in extracts from wine lees (WL) and grape pomace (GP). The biphasic solvent systems applied for HPCCC separation were n-butanol:methyl tert-butyl ether:acetonitrile:water (3:1:1:5) with 0.1% trifluoroacetic acid (TFA) and n-hexane:ethyl acetate:methanol:water (1:5:1:5). After refining the ethanol:water extracts of GP and WL by-products by ethyl acetate extraction, the latter system yielded an enriched fraction of the minor family of flavonols. Recoveries of 112.9 and 105.9 mg of purified flavonols (myricetin, quercetin, isorhamnetin, and kaempferol) in GP and WL, respectively, from 500 mg of ethyl acetate extract (equivalent to 10 g of by-product) were obtained. The HPCCC fractionation and concentration capabilities were also exploited for the characterization and tentative identification of constitutive PCs by ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS). In addition to the isolation of the enriched flavonol fraction, a total of 57 PCs in both matrixes were identified, 12 of which were reported for the first time in WL and/or GP. The application of HPCCC to GP and WL extracts may be a powerful approach to isolate large amounts of minor PCs. The composition of the isolated fraction demonstrated quantitative differences in the individual compound composition of GP and WL, supporting the potential exploitation of these matrixes as sources of specific flavonols for technological applications.

17.
Curr Res Food Sci ; 6: 100506, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37188318

RESUMO

Tannins, anthocyanins, and polymeric pigments are essential phenolic constituents of red wine because they provide color, color stability, and mouthfeel properties like astringency. The behavior of these compounds is significantly affected by pectic polysaccharides, whereby the extent of their influence on red wine quality depends on their structural features and their interactions with the polyphenols. In the present study, the composition of the pectic polysaccharides of commercially available Cabernet Sauvignon wines and their impact on anthocyanin, tannin, and polymeric pigment analyses was characterized. This was accomplished by preparation of polysaccharide deprived wines and comparison of the polyphenolic composition of both, the wines and their corresponding polysaccharide-free counterparts. The results show that the cell wall fragments enhance the spectral absorbance of anthocyanins by facilitating anthocyanin self-association, leading to a co-pigmentation-like effect. Low molecular weight pectins like rhamnogalacturonan II and polygalacturonic acids with a low degree of esterification are assumed to form soluble complexes with anthocyanins and also prevent protein precipitation of tannins, which was reduced by 6-13%. High molecular weight pectins with a high degree of esterification lead to the increased precipitability of pigments and tannins by a factor of 1.3 to 32.4 and 1.1 to 1.9, respectively, seemingly impairing the incorporation of anthocyanins in tannins to form precipitable polymeric pigments that are responsible for the longevity of red wine color. The increased precipitability of the pigments due to the interactions with the polysaccharides may indicate the formation of pigmented yet non-covalent aggregates that show comparable properties to the covalently formed precipitable pigments. The formation of those non-covalent structures may affect red wine color stability and astringency.

18.
Food Chem ; 425: 136473, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37295212

RESUMO

In view of the poor acceptance of synthetic food colorants by consumers, there is intense interest in novel natural compounds, preferably from plant-derived sources. We oxidized chlorogenic acid using NaIO4 and reacted the resultant quinone with tryptophan (Trp) to obtain a red-colored product. The colorant was precipitated, freeze-dried, purified by size exclusion chromatography, and subsequently characterized using UHPLC-MS, high-resolution mass spectrometry, and NMR spectroscopy. Additional mass spectrometric studies were performed on the reaction product generated with Trp educts labeled with 15N and 13C. The data obtained from these studies allowed the identification of a complex compound consisting of two Trp and one caffeic acid moieties, and the proposition of a tentative pathway of its formation. Thus, the present investigation expands our knowledge about the formation of red colorants based on the reaction of plant phenols and amino acids.


Assuntos
Ácido Clorogênico , Triptofano , Triptofano/química , Acoplamento Oxidativo , Ácido Clorogênico/análise , Espectrometria de Massas , Aminoácidos , Cromatografia Líquida de Alta Pressão
19.
Biochim Biophys Acta Biomembr ; 1865(4): 184137, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36746312

RESUMO

The effects of naringenin and the biflavonoids amentoflavone and tetrahydroamentoflavone on select bacterial lipids (carotenoids, fatty acids, and menaquinones) and membrane fluidity based on Laurdan generalized polarization were investigated. For this purpose, the pigment-forming food-associated microorganisms Staphylococcus xylosus (DSM 20266T and J70), Staphylococcus carnosus DSM 20501T, and Micrococcus luteus (ATCC 9341 and J3) were studied. The results suggest an envelope stress response by microorganisms due to flavonoids and an employment of adaptive mechanisms using carotenoids, fatty acids, and menaquinones. The flavonoid monomer naringenin impacted carotenoids, fatty acids, menaquinones, and membrane fluidity. Naringenin significantly influenced the carotenoid profile, particularly by an increase in the relative proportion of 4,4'-diaponeurosporenoic acid in Staphylococcus xylosus. Amentoflavone caused changes mainly in the membrane of Micrococcus luteus and decreased the menaquinone content. Tetrahydroamentoflavone mainly affected the carotenoids in the investigated strains. The noticeably different CCS value of tetrahydroamentoflavone compared to naringenin and amentoflavone revealed further insights into the structure-dependent effects of flavonoids. This study provides valuable insights into the response of pigment-forming food-associated microorganisms to naringenin, amentoflavone, and tetrahydroamentoflavone, which is important for the targeted and safe application of the latter as natural preservatives and useful for further research on the mechanisms of action.


Assuntos
Carotenoides , Flavonoides , Vitamina K 2 , Ácidos Graxos
20.
Curr Res Food Sci ; 6: 100518, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37303585

RESUMO

Sustainable processes accompanied by high extraction yields and minimized amounts of by-products are a major goal of current fruit juice production. Controlled degradation of cell wall polysaccharides, in particular pectin, may contribute to reduced emergence of side streams. Possible strategies for the optimization are the selection of enzyme preparations based on comprehensive studies of their activities, the adjustment of maceration temperature toward more gentle conditions, and the application of alternative technologies such as ultrasound (US) during maceration. The present study provides insights into the effects of ultrasound-assisted enzymatic maceration (UAEM) on pectin degradation, total anthocyanin content, thermal and storage stability, and juice yield during chokeberry juice production on pilot-plant scale. The two enzyme preparations applied predominantly possessed polygalacturonase or pectin lyase activity. Cell wall polysaccharide degradation was improved by US and resulted in a 3% increase in juice yield by UAEM using an enzyme preparation that shows mostly polygalacturonase activity. Thermostability of anthocyanins was improved in juices produced using pectin lyase and applying US and matched the stability of anthocyanins in juices produced using polygalacturonase. Storage stability of anthocyanins was improved in juice produced using polygalacturonase during UAEM. UAEM also resulted in lower yields of pomace making the production more resource-efficient. Overall, the use of polygalacturonase has promising potential to advance conventional chokeberry juice production by applying US at gentle conditions.

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