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1.
An Acad Bras Cienc ; 91(3): e20180140, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31508662

RESUMO

Ackee (Blighia sapida K. D. Koenig) is an exotic fruit widely consumed in the Caribbean countries. While there is extensive research on the presence of hypoglycin A, other bioactive compounds have not been studied. We identified and quantified the changes in bioactive molecules (total phenol, ascorbic acid, hypoglycin A, squalene, D: A-Friedooleanan-7-ol, (7.alpha.), and oleic acid), antioxidant potential, and volatile compounds during two stages of ripe. A clear reduction in hypoglycin A, ascorbic acid, and total polyphenols during the maturation process were observed. On the contrary, oleic acid, squalene, and D: A-Friedooleanan-7-ol, (7.alpha.) contents increased about 12, 12, and 13 times, respectively with advancing maturity. These bioactive molecules were positively correlated with radical scavenging (DDPH and ABTS). Solid phase microextraction (SPME) and gas chromatography coupled mass spectrometry (GC/MS) analysis revealed more than 50 compounds with 3-penten-2-one and hexanal as the major compounds in the fully ripe stage. The results suggested that ripe ackee arilli could serve as an appreciable source of natural bioactive micro-constituents.


Assuntos
Antioxidantes/farmacologia , Blighia/química , Frutas/química , Cromatografia Gasosa-Espectrometria de Massas , Hipoglicinas/química , Polifenóis/química , Esqualeno/química
2.
Bioresour Technol ; 291: 121860, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31374414

RESUMO

This study aims to enhance the quality of biofuel through microwave torrefaction pretreatment for lignin. Low density polyethylene (LDPE) was added as a hydrogen source during microwave co-pyrolysis along with the microwave-torrefied lignin (MTL). The thermal degradation behavior and kinetic study of MTL co-pyrolysis with LDPE by microwave-assisted heating was investigated as well. The results indicated that the hydrocarbon content in the bio-oil obtained from microwave co-pyrolysis of MTL and LDPE increased significantly (about 80%). It was also noticed that the aromatic hydrocarbon content increased from 1.94% to 22.83% with the addition of LDPE. Thermal behavior analysis and reaction kinetic study showed that the addition of LDPE into MTL had the effect of promoting thermal degradation and improving reaction rate during microwave-assisted pyrolysis.


Assuntos
Hidrocarbonetos/química , Lignina/química , Óleos Vegetais/química , Polietileno/química , Polifenóis/química , Temperatura Alta , Cinética , Micro-Ondas , Pirólise
3.
J Agric Food Chem ; 67(31): 8617-8625, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31293160

RESUMO

Inhibiting starch digestion can effectively control postprandial blood sugar level. In this study, the in vitro digestion differences among the mixtures of five polyphenols (i.e., procyanidins [PAs], catechin [CA], tannic acid [TA], rutin [RU], and quercetin [QU]) and starch were analyzed through an in vitro simulation test of starch digestion. The interaction characteristics of these five polyphenols with α-amylase and α-glucosidase were investigated in terms of the inhibition effect, dynamics, fluorescence quenching, and circular dichroism (CD). The results revealed that the rapidly digestible starch (RDS) contents decreased, while the resistant starch (RS) contents increased. All five polyphenols inhibited the α-amylase activity through the noncompetitive approach but inhibited the α-glucosidase activity through the competitive approach. Five polyphenols combined with α-amylase spontaneously by using the hydrophobic effect. The interaction of PAs and QU with α-glucosidase were recognized as van der Waals forces and H bonding, whereas CA and TA interacted with α-glucosidase through the hydrophobic effect. All five polyphenols can cause conformational changes in enzymes.


Assuntos
Extratos Vegetais/química , Polifenóis/química , Amido/química , Animais , Digestão , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Cinética , Modelos Biológicos , Extratos Vegetais/metabolismo , Polifenóis/metabolismo , Amido/metabolismo , Suínos , Leveduras/enzimologia , alfa-Amilases/química , alfa-Amilases/metabolismo , alfa-Glucosidases/química , alfa-Glucosidases/metabolismo
4.
Chem Biodivers ; 16(8): e1900205, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31294527

RESUMO

The importance of phenolic compounds for responding to various environmental conditions has been widely emphasized. However, the role of interactions between polyphenols and ecological factors, especially C, N, and P stoichiometry was little studied. Here, 15 sites across five provinces of Pinus bungeana in temperate regions of China were studied. The results showed that the higher values of total phenolic contents (TPC) of leaf and litter were distributed among the north distribution area of P. bungeana, lower values were in the south, whereas soil TPC were contrary to leaf and litter TPC. The stepwise regression, path analysis and decision index of path analysis for leaf TPC and ecological factors showed that altitude had the most direct impact on leaf TPC. Moreover, the principal determinants of leaf, litter and soil TPC were soil C/P ratios, longitude, and soil N/P ratios, respectively. In addition, the leaf, litter and soil TPC of P. bungeana were limited by soil C/N ratios, mean annual temperature, and soil P, respectively. Overall, our study provided evidence that ecological factors affected strongly the leaf, litter and soil TPC of P. bungeana.


Assuntos
Pinus/química , Polifenóis/química , Solo/química , Carbono/química , China , Colorimetria , Ecossistema , Nitrogênio/química , Fósforo/química , Pinus/metabolismo , Folhas de Planta/química , Folhas de Planta/metabolismo , Polifenóis/análise , Temperatura Ambiente
5.
J Agric Food Chem ; 67(28): 7855-7868, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31274310

RESUMO

Bee pollen (BP) collected from different floras possesses various potential bioactivities, but the mechanism-related research on anti-inflammatory effects is limited. Here, three types of BP originating from Camellia sinensis L. (BP-Cs), Nelumbo nucifera Gaertn. (BP-Nn), and Brassica campestris L. (BP-Bc) were assessed using molecular and metabolomics methods to determine their anti-inflammatory effects. The differences in polyphenolic abundance of three types of BP extracts were determined by HPLC-DAD/Q-TOF-MS. In vitro anti-inflammatory effects of three BP extracts were evaluated in a lipopolysaccharide (LPS)-induced RAW 264.7 cells model. BP-Cs extract with the most abundant polyphenols was found to be the most effective in reducing inflammation by downregulating inflammatory-related genes expression and blocking the activation of MAPK and NF-κB signaling pathways. Polyphenol-rich BP-Cs was further evaluated for their in vivo anti-inflammatory effect in a LPS-induced acute lung injury mouse model. An UPLC-Q-TOF/MS-based metabolomics approach was applied to analyze metabolite changes in mouse serum. Weshowed that the pretreated BP-Cs extract alleviated inflammation and regulated glycerophospholipid metabolism significantly. Our findings provide a foundation for developing and justifying BP as a potential anti-inflammatory ingredient in functional foods or nutraceutical formulations.


Assuntos
Lesão Pulmonar Aguda/tratamento farmacológico , Anti-Inflamatórios/administração & dosagem , Extratos Vegetais/administração & dosagem , Pólen/química , Lesão Pulmonar Aguda/genética , Lesão Pulmonar Aguda/imunologia , Animais , Anti-Inflamatórios/química , Abelhas , Brassica/química , Camellia sinensis/química , Cromatografia Líquida de Alta Pressão , Humanos , Lipopolissacarídeos/efeitos adversos , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Masculino , Espectrometria de Massas , Camundongos , Camundongos Endogâmicos ICR , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Quinases de Proteína Quinase Ativadas por Mitógeno/imunologia , NF-kappa B/genética , NF-kappa B/imunologia , Nelumbo/química , Extratos Vegetais/química , Polifenóis/administração & dosagem , Polifenóis/química , Células RAW 264.7
6.
Food Chem ; 299: 125051, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31284245

RESUMO

This study aims to exploit the molecular and cellular mechanisms concerning the functionality of dietary polyphenols (catechin, procyanidin B3, procyanidin C2, epigallocatechin and epigallocatechin gallate) in a nutritional context to prevent Celiac Disease (CD). In that sense, the interaction between the main CD bioactive peptide (32-mer peptide) and some polyphenols was fully characterized at the intestinal level under near physiological conditions by means of different spectroscopic techniques and dynamic simulations. Accordingly, it is proposed that the primarily polyphenol-binding sites on the 32-mer peptide correspond to leucine, tyrosine and phenylalanine containing domains being this interaction entropy-driven. Although procyanidin B3 and trimer C2 had a similar low-affinity constant at 310 K, both procyanidins were able to reduce the 32-mer peptide apical-to-basolateral translocation in in vitro simulated intestinal epithelial barrier thus prospecting the occurrence of additional and still unexplored regulatory mechanisms by which dietary polyphenols might modulate the transepithelial transport of CD bioactive peptides.


Assuntos
Alimentos , Glutens/química , Fragmentos de Peptídeos/química , Polifenóis/química , Análise Espectral , Glutens/metabolismo , Mucosa Intestinal/metabolismo , Fragmentos de Peptídeos/metabolismo , Ligação Proteica , Transporte Proteico
7.
Food Chem ; 299: 125025, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31295634

RESUMO

Peanut allergy is usually lifelong and accidental exposure impose formidable risk. The aim of this study was to assess the capacity of peanut proteins complexed to polyphenol extracts to reduce allergic response in C3H/HeJ mice. Mice were sensitized to peanut flour followed by exposure to amino acid diets fortified with peanut protein-polyphenol aggregates of either with low (15%; w/w) or high (40%; w/w) complexation ratios of blueberry (BB-Low and BB-High) and cranberry (CB-Low and CB-High) extracts. Treatment groups on diets with high complexation ratios of blueberry and cranberry aggregates showed significant reduction in peanut specific plasma Immunoglobulin E (IgE). Western blot analysis of spleen lysates showed CD63 protein expression was reduced in a dose-dependent manner in blueberry and cranberry complexed peanut protein supplemented diet groups. Our results demonstrate for the first time that complexation of polyphenols to peanut flour can potentially lower plasma IgE of peanut-sensitized C3H/HeJ mice.


Assuntos
Arachis/química , Arachis/imunologia , Imunoglobulina E/imunologia , Hipersensibilidade a Amendoim/prevenção & controle , Proteínas de Plantas/química , Proteínas de Plantas/imunologia , Polifenóis/química , Animais , Feminino , Camundongos , Camundongos Endogâmicos C3H , Especificidade da Espécie
8.
AAPS PharmSciTech ; 20(6): 250, 2019 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-31297635

RESUMO

Melanoma is regarded as the fifth and sixth most common cancer in men and women, respectively, and it is estimated that one person dies from melanoma every hour in the USA. Unfortunately, the treatment of melanoma is difficult because of its aggressive metastasis and resistance to treatment. The treatment of melanoma continues to be a challenging issue due to the limitations of available treatments such as a low response rate, severe adverse reactions, and significant toxicity. Natural polyphenols have attracted considerable attention from the scientific community due to their chemopreventive and chemotherapeutic efficacy. It has been suggested that poorly soluble polyphenols such as curcumin, resveratrol, quercetin, coumarin, and epigallocatechin-3-gallate may have significant benefits in the treatment of melanoma due to their antioxidant, anti-inflammatory, antiproliferative, and chemoprotective efficacies. The major obstacles for the use of polyphenolic compounds are low stability and poor bioavailability. Numerous nanoformulations, including solid lipid nanoparticles, polymeric nanoparticles, micelles, and liposomes, have been formulated to enhance the bioavailability and stability, as well as the therapeutic efficacy of polyphenols. This review will provide an overview of poorly soluble polyphenols that have been reported to have antimetastatic efficacy in melanomas.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Melanoma/tratamento farmacológico , Polifenóis/administração & dosagem , Polifenóis/química , Neoplasias Cutâneas/tratamento farmacológico , Animais , Antioxidantes/administração & dosagem , Antioxidantes/química , Antioxidantes/metabolismo , Disponibilidade Biológica , Catequina/administração & dosagem , Catequina/análogos & derivados , Catequina/química , Catequina/metabolismo , Curcumina/administração & dosagem , Curcumina/química , Curcumina/metabolismo , Humanos , Melanoma/metabolismo , Melanoma/prevenção & controle , Nanopartículas/administração & dosagem , Nanopartículas/química , Nanopartículas/metabolismo , Polifenóis/metabolismo , Quercetina/administração & dosagem , Quercetina/química , Quercetina/metabolismo , Resveratrol/administração & dosagem , Resveratrol/química , Resveratrol/metabolismo , Neoplasias Cutâneas/metabolismo , Solubilidade
9.
Food Chem ; 298: 125068, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260977

RESUMO

In this work, 18 gluten-free flours (prepared from cereals, pseudocereals and legumes), differing in pigmentation, were screened for their phenolic profiles, cooked and, then, subjected to digestion and large intestinal fermentation in vitro. A combined targeted/untargeted metabolomic approach was used to elucidate the microbial biotransformation processes of polyphenols following digestion. This preliminary work demonstrated an increase in 3,5-dihydroxybenzoic acid (on average from 0.67 up to 1.30 µmol/g dry matter) throughout large intestinal fermentation of pseudocereals (esp. quinoa), due to their high alkylresorcinol contents. Isoflavones were converted into equol- or O-desmethylangolensin- derivatives, whereas anthocyanins were degraded into lower-molecular-weight phenolics (i.e., protocatechuic aldehyde and 4-hydroxybenzoic acid, with the latter exhibiting the highest increase over time). A decreasing trend was observed for antioxidant activities (i.e., FRAP and ORAC values) moving from digested to faecal fermented samples. These findings highlight that gluten-free flours are able to deliver bioaccessible polyphenols to the colon.


Assuntos
Farinha/análise , Intestino Grosso/microbiologia , Polifenóis/metabolismo , Animais , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Técnicas de Cultura Celular por Lotes , Cromatografia Líquida de Alta Pressão , Culinária , Fezes/microbiologia , Polifenóis/análise , Polifenóis/química , Espectrometria de Massas por Ionização por Electrospray , Suínos
10.
Food Chem ; 299: 125097, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31284242

RESUMO

The low solubility, instability, and low bioavailability of food bioactive compounds such as polyphenols and flavonoids, restrict their applications in the fields of food science and nutrition. Ferritin protein has received more and more attention in encapsulation and delivery of the bioactive compounds due to its nanosized shell-like structure and its reversible self-assembly character. After encapsulation, bioactive compounds can be functionalized by the ferritin vehicle to achieve stabilization, solubilization, and targeted delivery. In addition, the outer interfaces and the porous structure of ferritin are also artfully harnessed for encapsulation. This review focuses on the newest advances in the fabrication, characterization, and application of ferritin-based nano-carriers for bioactive compounds by the reversible self-assembly, outer-interface decoration methods, and the channel-directed approach. The functional improvements of food bioactive compounds, including their solubility, stability, and cellular uptake, are emphasized. The limitations that affect ferritin encapsulation are also examined.


Assuntos
Ferritinas/química , Ferritinas/farmacocinética , Alimentos , Nanoestruturas/química , Antocianinas/administração & dosagem , Antocianinas/química , Antocianinas/farmacocinética , Disponibilidade Biológica , Catequina/análogos & derivados , Catequina/química , Quitosana/química , Curcumina/administração & dosagem , Curcumina/química , Curcumina/farmacocinética , Humanos , Polifenóis/administração & dosagem , Polifenóis/química , Polifenóis/farmacocinética , Proantocianidinas/administração & dosagem , Proantocianidinas/química , Proantocianidinas/farmacocinética , Solubilidade , beta Caroteno/administração & dosagem , beta Caroteno/química , beta Caroteno/farmacocinética
11.
Food Chem ; 299: 125094, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31301529

RESUMO

The jaggery-making process involves various thermo-chemical treatments of sugarcane juice. As jaggery making is a traditional practice, knowledge about the use of different chemicals in the process is transferred from generation to generation without much scientific understanding. Phosphoric acid is one of the chemicals commonly used in this process. We have investigated its effect through systematic experiments. The addition of acid causes inversion of sucrose, which beyond a certain point is not desirable for good quality jaggery. In the correct proportions, however, phosphoric acid improves the colour and texture of jaggery and helps in the formation of smaller sized crystals. Reducing sugars formed due to inversion hinder crystal growth, resulting in relatively small crystals. In our experiments, the average crystal size reduced from 22.22 µm to 14.34 µm. Acid-treatedjaggery was found to equilibrate at higher moisture. A comparison with normal jaggery is thus provided for its keeping quality.


Assuntos
Indústria de Processamento de Alimentos/métodos , Ácidos Fosfóricos/química , Extratos Vegetais/química , Saccharum/química , Cor , Cristalização , Flavonoides/química , Monossacarídeos/análise , Extratos Vegetais/análise , Polifenóis/química
12.
Food Chem ; 297: 125008, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253286

RESUMO

The formation of toxic and potentially carcinogenic acrylamide, alongside volatile aroma compounds, was studied after polyphenols ((+)-catechin, quercetin, gallic, ferulic, caffeic acids) were added to model bread. The addition of as little as 0.1% polyphenols to bread significantly reduced acrylamide (16.2-95.2%). In the case of quercetin, a promoting effect was observed (+9.8%) when its concentration increased. Of all the phenolic compounds, regardless of concentration, ferulic acid showed the highest level of acrylamide inhibition. This is probably due to the presence of 4-vinylguaiacol, a degradation derivative with strong antioxidant activity in heterogeneous systems. Although the phenolic compounds mitigate acrylamide, this adversely affected bread volatile profile. At the highest level (2.0%), caffeic acid most significantly suppressed Maillard-type volatiles (75.9%), followed by gallic acid (74.3%), ferulic acid (65.6%), (+)-catechin (62.4%), and quercetin (59.3%). Among polyphenols, ferulic acid decreased yeast fermentation products level the most (33.1%), simultaneously enhancing lipid oxidation product, probably due to inhibition of amylases and yeast activity.


Assuntos
Acrilamida/química , Pão/análise , Polifenóis/química , Triticum/metabolismo , Compostos Orgânicos Voláteis/química , Acrilamida/análise , Antioxidantes/química , Análise por Conglomerados , Ácidos Cumáricos/química , Cromatografia Gasosa-Espectrometria de Massas , Reação de Maillard
13.
Food Chem ; 293: 127-133, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151592

RESUMO

Dried persimmon is thought to be a rich source of non-extractable polyphenols (NEPPs). Here, we analyzed the NEPP content of dried persimmon and its bile acid-binding activity in vitro. To determine total NEPP content and epicatechin equivalent (ECE) of intact NEPPs, acid hydrolysis and non-destructive methods with 70% (v/v) acetone-insoluble solids (AIS), respectively, were conducted using Folin-Ciocalteu reagent. The ECE of intact NEPPs exceeded 1000 mg/100 g in the non-destructive method, but total NEPP content was approximately 3900 mg/100 g with the acid hydrolysis method. Thiolysis showed that the non-extractable proanthocyanidins in dried persimmon mainly comprised epigallocatechin-gallate, epigallocatechin, epicatechin, and epicatechin-gallate. AIS from dried persimmon showed stronger bile acid-binding activity than AIS from apple, quince, and fresh astringent persimmon. These results suggest that the high content of NEPPs in dried persimmon may contribute to a strong bile acid-binding activity.


Assuntos
Ácidos e Sais Biliares/química , Diospyros/química , Polifenóis/química , Cromatografia Líquida de Alta Pressão , Diospyros/metabolismo , Frutas/química , Frutas/metabolismo , Hidrólise , Espectrometria de Massas , Molibdênio/química , Polifenóis/análise , Proantocianidinas/análise , Proantocianidinas/química , Compostos de Tungstênio/química
14.
Food Chem ; 295: 423-431, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174778

RESUMO

Effects of natural phenolics on the shelf life of dried scallop adductor muscle predicted by accelerated shelf life testing (ALST) combined with Arrhenius model were investigated. This allows the food industries to reliably and rapidly determine the shelf life of dried shellfish species treated with antioxidants. The shelf life of dried scallop adductor muscle treated with antioxidants of bamboo leaves (AOB) and tea polyphenols (TP) was more than 1.70-fold that of dried control scallop adductor muscle. Thus, the highly nutritional value of dried scallop adductor muscle, based on its lipid constituents, is maintained during storage. OXITEST method further confirmed the improvement of lipid stability of antioxidant treated dried scallop adductor muscle by protecting polyunsaturated fatty acids, especially eicosapentaenoic and docosahexaenoic acids, against autoxidation. Moreover, the natural phenolics employed effectively limited lipid oxidation by breaking the autoxidative chain reaction and/or inhibiting free radical formation in dried scallop adductor muscle during storage.


Assuntos
Armazenamento de Alimentos , Lipídeos/química , Pectinidae/química , Polifenóis/química , Frutos do Mar , Animais , Antioxidantes/química , Camellia sinensis/química , Ácidos Graxos Insaturados/análise , Ácidos Graxos Insaturados/química , Liofilização , Músculo Esquelético/química , Valor Nutritivo , Oxirredução , Folhas de Planta/química , Carbamilação de Proteínas , Sasa/química
15.
Food Chem ; 296: 142-149, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31202298

RESUMO

Little data are available on the impact of pomace pre-treatment, notably drying, on the nature and yield of polyphenols. Pomace from two apple varieties ('Avrolles' and 'Kermerrien'), pressed with and without oxidation, were air-dried to different degrees. Drying led to the loss of native molecules, notably 5-O-caffeoylquinic acid and flavan-3-ols. Total polyphenol yields, after sequential pressurized liquid extraction (water 10 MPa, 70 °C, then ethanol 48%, 10 MPa, 70 °C), varied between 5 and 15 g/kg dry weight but showed no marked trend with drying. Extracts from dried pomace contained few native polyphenols. Water extracts from 'Kermerrien' contained flavonols, flavanols and phloridzin and those from 'Avrolles' contained phloridzin. Water:ethanol extracts were rich in procyanidins, especially from 'Avrolles', where they represented >80% of analysable polyphenols. Presence of polyphenol molecules with modified structures in the extracts of dried pomaces might lead to different biological properties than those with native molecules.


Assuntos
Dessecação/métodos , Malus/química , Extratos Vegetais/química , Polifenóis/química , Flavanonas/química , Malus/metabolismo , Polifenóis/isolamento & purificação , Polissacarídeos/química , Proantocianidinas/química
16.
J Agric Food Chem ; 67(26): 7506-7511, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31184879

RESUMO

The poor water solubility and oral bioavailability of many lipophilic polyphenols can be improved through the use of colloidal delivery systems. In this study, a pH-driven method was used to encapsulate curcumin, quercetin, and resveratrol within nanoliposomes. This method is based on the decrease in water-solubility of certain polyphenols when they move from alkaline to acid conditions. However, the chemical stability of some polyphenols is relatively poor under alkaline conditions. For this reason, the impact of pH on the chemical degradation of the three polyphenols was studied. The polyphenols were then encapsulated within nanoliposomes using the pH-driven method and the encapsulation efficiency (EE) and chemical stability were determined. The EE of curcumin, quercetin, and resveratrol in the nanoliposomes was 100, 54, and 93%, respectively. Differences in the EE were mainly attributed to differences in their stability under alkaline conditions. Our results show that the application of this method to other lipophilic polyphenols depends on the impact of pH on their solubility and chemical stability, which needs to be established on a case-by-case basis.


Assuntos
Composição de Medicamentos/métodos , Lipossomos/química , Nanopartículas/química , Polifenóis/química , Disponibilidade Biológica , Curcumina/química , Portadores de Fármacos/química , Concentração de Íons de Hidrogênio , Quercetina/química , Resveratrol/química , Solubilidade
17.
J Agric Food Chem ; 67(26): 7428-7434, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31187991

RESUMO

Protein-polyphenol interactions play a very important role in wine stability assessment, especially in red varieties. Different polysaccharides can influence these interactions by protecting or disrupting charges and are even used as additives to stabilize colloidal solutions. The most common examples are mannoproteins and carboxymethyl cellulose (CMC). In some cases, the mechanisms that are involved in these reactions are not thoroughly understood and can lead to unexpected problems and delayed haze formation after CMC addition to red wines. Small-scale bench trials were conducted in model systems under different pH conditions to monitor the formation of turbidity and protection mechanisms during the interaction of proteins, polyphenols, and polysaccharides. Egg-white protein was chosen as a protein model due to its complex composition, a commercial grape tannin extract was used as polyphenol source, and pectin, glucomannan, mannoprotein, alginate, and CMC were applied as polysaccharides to model various wine conditions. Reactions were monitored in duplicate on a 50 mL scale by spectrophotometry at 860 nm over at least 30 days. Some of the polysaccharides interacted directly with proteins or polyphenols causing precipitation. Other polysaccharides delayed the reaction between proteins and other macromolecules depending on their concentration. The results of these experiments provide important insights into reaction dynamics between macromolecules that are involved in the physical stability of wine.


Assuntos
Carboximetilcelulose Sódica/química , Proteínas do Ovo/química , Extratos Vegetais/química , Polifenóis/química , Polissacarídeos/química , Vinho/análise , Animais , Galinhas , Glicoproteínas de Membrana/química , Taninos/química , Vitis/química
18.
Food Chem ; 297: 124910, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253292

RESUMO

Polyphenols can inhibit the enzymatic browning in food, but their indistinct synergistic effect and conformational change have limited their applications. In this paper, the mixture of quercetin, cinnamic acid and ferulic acid (Group 11, KI = 0.239 mM) possessed a higher inhibition ability than quercetin (KI = 0.361 mM), which could promote the spontaneous binding process. The final Group 11-tyrosinase complex is more stable, and the hydrophobic effect is the major driving force during the binding process. Moreover, there is not a direct relationship between the destruction of secondary structures and catalytic activity of tyrosinase. The interaction between ferulic acid and tyrosinase could destroy the secondary structures of enzyme but it had little impact on the tyrosinase activity. Molecular docking suggested that three polyphenols from Group 11 have synergistic effect on tyrosinase. This study provides new perspectives about the development of tyrosinase inhibitors in food products.


Assuntos
Inibidores Enzimáticos/química , Monofenol Mono-Oxigenase/antagonistas & inibidores , Polifenóis/química , Sítios de Ligação , Cinamatos/química , Cinamatos/metabolismo , Ácidos Cumáricos/química , Ácidos Cumáricos/metabolismo , Inibidores Enzimáticos/metabolismo , Cinética , Simulação de Acoplamento Molecular , Monofenol Mono-Oxigenase/metabolismo , Estrutura Secundária de Proteína , Termodinâmica
19.
Food Chem ; 293: 463-471, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151635

RESUMO

Covalent modification of flaxseed protein isolate by phenolic compounds including flaxseed polyphenols, ferulic acid, and hydroxytyrosol was studied under alkaline condition and in the presence of oxygen. The structure and function of the adducts was evaluated. The extent of covalent reaction and the physicochemical characteristics of flaxseed protein isolate-phenolic adducts were found to depend on the structure of the phenolic compounds. The decrease in free amino, thiol and tryptophan groups and increase in molecular weight were different. Crosslinks were found in flaxseed protein isolate-hydroxytyrosol adducts while ferulic acid and flaxseed polyphenols were unable to crosslink flaxseed proteins. The thermal stability and antioxidative capacity of the adducts were higher than those of flaxseed protein isolate. The structural conformation and hydrophobicity of the adducts were also found to depend on the nature of phenolic compounds. These adducts can be used in food formulations as natural antioxidants, emulsifiers and encapsulating shell materials.


Assuntos
Linho/metabolismo , Fenóis/química , Proteínas de Plantas/química , Antioxidantes/química , Ácidos Cumáricos/química , Linho/química , Concentração de Íons de Hidrogênio , Álcool Feniletílico/análogos & derivados , Álcool Feniletílico/química , Proteínas de Plantas/metabolismo , Polifenóis/química , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície
20.
Plant Physiol Biochem ; 141: 407-414, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31228797

RESUMO

Polyphenols are constituents of all higher plants. However, their biosynthesis is often induced when plants are exposed to abiotic stresses, such as drought. The aim of the present work was to determine the phenolic status in the roots of olive trees grown under water deficit conditions. The results revealed that roots of water-stressed plants had a higher content of total phenols. The main compound detected in well-watered olive tree roots was verbascoside. Oleuropein was established as the predominant phenolic compound of water-stressed plants. The oleuropein/verbascoside ratio varied between 0.31 and 6.02 in well-watered and water-stressed plants respectively, which could be a useful indicator of drought tolerance in olive trees. Furthermore, this study is the first to provide experimental evidence showing that luteolin-7-rutinoside, luteolin-7-glucoside and apigenin-7-glucoside were the dominant flavonoid glucosides in olive tree roots and showed the most significant variations under water stress.


Assuntos
Secas , Iridoides/química , Olea/fisiologia , Raízes de Plantas/fisiologia , Antioxidantes/química , Apigenina/química , Flavonoides/química , Glucosídeos/química , Fenol/química , Fenóis/química , Álcool Feniletílico/análogos & derivados , Álcool Feniletílico/química , Extratos Vegetais/química , Folhas de Planta/fisiologia , Polifenóis/química , Espectrofotometria Ultravioleta , Estresse Fisiológico , Água
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