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1.
Chem Biodivers ; 2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-32311206

RESUMO

A large number of biologically active compounds are present in ripe citrus fruits . However, few studies have been focused on the changes in flavonoids and the evolution of antioxidant activity during citrus fruit growth. In this study, fruits of five citrus cultivars cultivated in China were sampled at 60 - 210 days post-anthesis (DPA) at intervals of 30 days. The contents of main flavonoids in the peel and pulp were analyzed by HPLC and their activities were studied by DPPH, ABTS and FRAP. The results showed that the contents of hesperidin, diosmin, eriodictyol, rutin and nobiletin increased before 90 DPA and then decreased with the growth and development of fruits, but an opposite tendency was observed for naringin and narirutin. The antioxidant activities in citrus peel and pulp were found to be significantly correlated with some flavonoids. The results may be of guiding values in citrus production and utilization of citrus fruit by-products.

2.
Food Funct ; 11(4): 3167-3179, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32208477

RESUMO

The barrier-improving functions of fermented blueberry pomace (FBP) and its potential mechanism were investigated in this study. Polyphenols and the approximate composition of FBP were evaluated according to the National Standard of the People's Republic of China and the UPLC-MS system. Male C57BL/6 mice were fed a control diet (CD) or a high-fat diet (HFD) with or without FBP supplementation. Oxidative stress, inflammation, histological morphology and the expression of functional proteins in the small intestine of mice were evaluated using the enzyme linked immunosorbent assay (ELISA), quantitative polymerase chain reaction (qPCR) and western blotting. The content of protein, fat, soluble dietary fiber, insoluble dietary fiber and carbohydrates (non-dietary fiber) was 114.5 ± 1.5 g kg-1, 5.0 ± 0.2 g kg-1, 48.0 ± 0.1 g kg-1, 360.3 ± 2.2 g kg-1 and 423 g kg-1 (by difference), respectively. Thirty-six polyphenols were identified in FBP. FBP improved the growth of mice and attenuated hepatic and intestinal oxidative stress. Intestinal inflammation was significantly reduced through the decrease of tumor necrosis factor-alpha (TNF-α) and myeloperoxidase (MPO) as well as an increase of interleukin-10 (IL-10). FBP supplementation significantly improved the intestinal morphology and barrier function, potentially by mediating the NF-κB-MLCK signaling pathway. The supplementation of FBP in HFD mice enhanced the intestinal barrier function. This suggested that polyphenol-rich by-products might provide a similar health effect in HFD individuals.

3.
Biomacromolecules ; 21(2): 670-679, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-31794666

RESUMO

Computational and experimental methods were applied to investigate the self-assembly and gelation of C13-dipeptides. A modified aggregation propensity (APS) was introduced to correlate the effects of side chains of amino acids on the tendency to aggregate. From the experimental results, the ranges of 0.156 < APS < 0.250 seemed to be a proper region for the C13-dipeptides to form hydrogels, while other molecules with higher or lower APS were insoluble or dissociated. As observed from molecular dynamics simulations, the C13-dipeptides first formed small aggregates through hydrophobic interactions and then rearranged through electrostatic attractions and hydrogen bonds for self-assembly. The C13-dipeptides tended to be antiparallel packed, as shown by hydrogen bonding analyses. Experimental observations and analyses on the structures of C13-dipeptide hydrogels matched the computational conclusions very well. From the five selected gelators, i.e., C13-GW, C13-VY, and C13-WT, strong π-π stacking was observed. For C13-WS, strong hydrogen bonding was found, and in C13-WY, both strong π-π interactions and hydrogen bonds were found. It takes around 90 min or longer for C13-dipeptides to form hydrogels, and those formed by C13-WY and C13-WS had weak water holding capacities, which might be due to strong intermolecular hydrogen bonding. From rheological studies, the C13-dipeptides formed strong chemical gels that were stabilized by strong interactions between the molecular aggregates. These gelators exhibit the potentials to be environmentally friendly substitutes for the common functionalized peptide gelators.

4.
J Sep Sci ; 43(4): 756-765, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31722132

RESUMO

Three types of molecularly imprinted solid-phase microextraction fibers were fabricated through sol-gel method using diazinon, parathion-methyl, and isocarbophos as templates, respectively, and assembled together to construct a multifiber for analysis of organophosphorus pesticides in complex matrices. The multifiber provided large extraction capacity and high imprinting factor up to 3.89. In contrast, the imprinting factor of a single fiber was around 1.6, and the multi-template imprinted coating showed no selectivity. The multifiber was applied to analyze pesticides in fruits and vegetables. The limits of detection, which ranged from 0.0052 to 0.23 µg/kg, were lower than those obtained by a single molecularly imprinted fiber, and much lower than those reported by other methods. The recoveries of five analytes in spiked apple, cucumber, Chinese cabbage, and cherry tomato samples were 75.1-123.2%. The study shows that the molecularly imprinted multifiber could achieve simultaneous selective extraction and sensitive determination of multiple targets in complex matrices for high-throughput analysis.

5.
Molecules ; 24(24)2019 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-31817260

RESUMO

An in situ tracing study based on solid-phase microextraction (SPME) was conducted to investigate the uptake and elimination of organophosphorus pesticides in apples. A matrix-compatible polydimethylsiloxane/poly(styrene-co-divinylbenzene)/polydimethylsiloxane fiber was produced to meet the needs of in situ sampling. The fiber had high extraction ability, good sensitivity and accuracy with respect to the analytes in apple pulp, and could be used 85 times. Although the sampling rate was changing over time, quantification was still achieved by the sampling rate calibration method. Some factors that affect its applicability were studied. The limits of detection were 0.18 ng/g for diazinon and 0.20 ng/g for chlorpyrifos, rather lower than the maximum residue limits of the National Food Safety Standard of China (GB 2763-2016) and the European Commission (Reg.(EU) No 834/2013, 2018/686). The accuracy of in situ SPME quantification was verified by comparing with the results obtained by the traditional liquid-liquid extraction method. In this work, the in situ sampling method is developed using apples, diazinon, and chlorpyrifos as a model system; however, this method can be used for in vivo analysis of fruits and vegetables for nutrition and safety monitoring.

6.
Molecules ; 24(23)2019 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-31766733

RESUMO

The effects of ultrasonic-assisted extraction (UAE, 200 W, 20 min) on the yield and physicochemical properties of different walnut proteins (WNPs, including albumin, globulin, and glutelin) were investigated. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis indicated that UAE could result in protein molecular fragmentation of albumin, but did not affect the major bands of globulin and glutelin. The CD spectra demonstrated that different WNPs obtained by UAE had different changes in their secondary structure. Under UAE, there was an increase in surface hydrophobicity (H0) of albumin and gluten and no change in the fluorescence intensity, while decreases were observed in the H0 and fluorescence intensity of globulin; and the contents of total and surface free sulfhydryl in albumin dramatically decreased. UAE reduced the size of the particles and the dimension of the microstructures in albumin and gluten, indicating that ultrasound could unfold protein aggregates. In addition, UAE increased the solubility, emulsifying activity (EA), foaming capacity (FC), and foam stability (FS) of the obtained proteins. The above results indicate that ultrasound extraction is a promising approach to improve the extraction yield and properties of walnut proteins.

7.
J Food Sci Technol ; 56(10): 4492-4502, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31686681

RESUMO

In the present study, peel oils were extracted through hydrodistillation and cold pressing from three Citrus species (Valencia orange, Ponkan and Eureka lemon) to investigate their volatile constituents and antioxidant activities. A total of 47 volatile components were identified by GC-MS, and then grouped by principal component analysis. The extraction methods were found to have an obvious effect on the proportion of terpenes and oxygenated compounds in the six Citrus oils, especially for Eureka lemon oils. The major fractions in the Citrus oils were found to be monoterpenes (78.65-96.57%), with limonene occupying a dominant percentage (51.22-86.65%). Furthermore, γ-terpinene and terpinolene displayed strong DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging abilities and efficient inhibition of lipid peroxidation, while oxygenated compounds of α-terpineol and terpinen-4-ol showed poor DPPH radical-scavenging abilities. Therefore, hydrodistillated Eureka lemon oil with high levels of α-terpineol (9.11%) and terpinen-4-ol (4.69%) presented low radical scavenging capability. Citral displayed a high pro-oxidant ability against thiobarbituric acid reactive species formation, which might lead to the decreased ability of the Eureka lemon oils in inhibition of lipid peroxidation, since citral was significantly high in Eureka lemon oils. This study facilitated the understanding of volatile constituents and antioxidant activities in different Citrus peel oils.

8.
J Agric Food Chem ; 67(43): 11922-11930, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31576748

RESUMO

We investigated the regulatory effects of citrus pectin oligosaccharides (POS) from an innovative, chemically controllable degradation process on cholesterol metabolism and the gut microbial composition. The modulatory role of the intestinal flora was explored. Four-week-old male C57BL/6 mice were fed either a standard diet; a high-fat (HF) diet; or a HF diet with 0.15, 0.45, and 0.9 g/kg body weight POS for 30 days. POS reduced serum total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C) in a dose-dependent manner. The relative abundances of specific bacterial groups in the feces and the concentrations of their metabolites were higher in the POS groups. There were significant correlations among Bifidobacterium, Lactobacillus, and Bacteroides and short-chain fatty acids, as well as among serum TC, LDL-C, fecal bile acids, and liver cholesterol 7-α-hydroxylase and 3-hydroxy-3-methylglutaryl-coenzyme A reductase. These findings indicate that the prepared POS exhibited hypocholesterolemic effects and that the potential regulatory mechanisms of citrus POS on cholesterol metabolism are modulated by specific bacterial groups together with their metabolites.


Assuntos
Anticolesterolemiantes/administração & dosagem , Colesterol/metabolismo , Citrus/química , Microbioma Gastrointestinal , Hipercolesterolemia/tratamento farmacológico , Oligossacarídeos/administração & dosagem , Pectinas/administração & dosagem , Extratos Vegetais/administração & dosagem , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , LDL-Colesterol/metabolismo , Dieta Hiperlipídica/efeitos adversos , Ácidos Graxos Voláteis/metabolismo , Fezes/microbiologia , Humanos , Hipercolesterolemia/metabolismo , Hipercolesterolemia/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL
9.
Carbohydr Polym ; 226: 115285, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31582075

RESUMO

The gel behavior of low methoxyl pectin (LMP) de-esterified by high hydrostatic pressure-assisted enzymatic (HHP-pectin, 400 MPa/40 °C/12 min), atmospheric enzymatic (E-pectin, 40 °C/2 h), and alkaline method (A-pectin, pH = 12/25 °C/25 min) was comparatively investigated, with regard to gel strength, water-holding capacity (WHC), rheological properties, and microstructure of pectin gels. Results showed that the de-esterification method had a strong influence on gelling properties of LMPs. The gelation of all LMPs was significantly affected by pectin, Ca2+ concentration and pH of the solution, but enzymatically de-esterified LMPs formed gels with higher gel strength, WHC and better viscoelasticity than those from alkaline de-esterified method. HHP-pectin gels showed even higher gel strength at the same Ca2+ concentrations and better WHC at the same pH, as compared to those from E-pectin. Moreover, the de-esterification time for HHP-pectin was much shorter than that for E-pectin. These findings indicated that HHP could be a potential alternative for high efficient pectin de-esterification, preparing LMPs with better gelling property.

10.
Ultrason Sonochem ; 58: 104627, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31450289

RESUMO

In this study, high intensity ultrasound (HIU) was used to produce food protein stabilized emulsions under different ionic strengths (0, 25, 50, 100, 200 and 300 mM NaCl). Five plant and animal food proteins, whey protein isolate (WPI), soy protein isolate (SPI), bovine gelatin, peanut protein isolate (PPI) and corn zein were selected as protein emulsifiers. PPI and zein could not form emulsions using ultrasound emulsification at all ionic strengths (from 0 to 300 mM NaCl). However, ultrasound could induce stable emulsions using SPI, WPI and gelatin as emulsifiers. Moreover, different ionic strengths and protein types influenced the physicochemical properties of HIU induced emulsions obviously. It was found that the droplet sizes of gelatin emulsions were lower than those of SPI and WPI emulsions at salt concentrations of 300 mM NaCl. Furthermore, gelatin emulsions had better stability against environmental stresses (salt and temperature) than that of SPI and WPI emulsions. Moreover, the adsorbed protein (%) at the oil/water interface of SPI emulsions was higher than those of WPI and gelatin emulsions. However, the adsorbed protein amount of all proteins stabilized emulsions increased significantly after salt addition. The absolute ζ-potential values decreased with the increase of salt concentrations. The microrheology results indicated that the SPI emulsions formed a gel-like structure at high salt concentrations (>50 mM NaCl) as SPI emulsions exhibited higher elasticity than WPI and gelatin emulsions. In conclusion, the ultrasound as a green emulsification technique could be used to fabricate emulsions stabilized by plant and animal proteins.


Assuntos
Fenômenos Químicos , Concentração Osmolar , Proteínas de Plantas/química , Ondas Ultrassônicas , Animais , Emulsões , Estabilidade Proteica , Propriedades de Superfície , Temperatura
11.
Food Chem X ; 2: 100025, 2019 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-31432012

RESUMO

The aim of this study was to examine both physiological and molecular evidences related to fruit discoloration in postharvest strawberries under high ambient temperature. The results showed the total anthocyanin and their main components in the strawberries under 35 °C were greatly increased due to the significant up-regulations of anthocyanin biosynthetic genes and transportation genes. High ambient temperature greatly improved the activities of peroxidase (POD) and enhanced gene expressions of POD3, POD6 and POD63. At the same time, high storage temperature activated laccase genes expression including laccase-9 and laccase-14, which was closely related to anthocyanin degradation. Levels of reactive oxygen species (ROS) metabolism were also increased under high ambient temperature at transcript levels. Therefore, we concluded that high ambient temperature could enhance anthocyanin accumulation and degradation at the same time, which maybe the main reasons for the fruits discoloration of postharvest strawberries under high ambient temperature.

12.
Biofactors ; 45(4): 563-574, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31131946

RESUMO

Isoflavones are one group of the major flavonoids and possess multiple biological activities due to their antioxidant properties. However, a clear antioxidant mechanism of dietary isoflavones is still remained to be answered. In this study, the effects of isoflavones on the nuclear factor E2-related factor 2 (Nrf2)-antioxidant response element (ARE) signaling pathway and the underlying molecular mechanisms were investigated. Results showed that isoflavones are potential Nrf2-ARE activators while their activities were structure dependent. Biochanin A (BCA), an O-methylated isoflavone with low direct antioxidant activity, can effectively protect HepG2 cells against tert-butyl hydroperoxide (t-BHP)-induced oxidative damage via activation of the Nrf2 signaling, and thereby the induction of downstream cytoprotective enzymes including NAD(P)H quinone oxidoreductase-1, heme oxygenasae-1, and glutamate-cysteine ligase catalytic subunit. A molecular docking study revealed that BCA could directly bind into the pocket of Kelch-like erythroid cell-derived protein with CNC homology (ECH)-associated protein 1 (Keap1), a cytoplasmic suppressor of Nrf2, to facilitate Nrf2 activation. The upstream mitogen-activated protein kinase (MAPK) pathways were also involved in the activation of Nrf2 signaling. These findings indicate that the protective actions of dietary isoflavones against oxidative damage may be at least partly due to their ability to enhance the intracellular antioxidant response system by modulating the Nrf2-ARE signaling pathway.


Assuntos
Elementos de Resposta Antioxidante/efeitos dos fármacos , Antioxidantes/farmacologia , Genisteína/farmacologia , Proteínas Quinases Ativadas por Mitógeno/genética , Fator 2 Relacionado a NF-E2/genética , Espécies Reativas de Oxigênio/antagonistas & inibidores , Sobrevivência Celular/efeitos dos fármacos , Regulação da Expressão Gênica , Glutamato-Cisteína Ligase/genética , Glutamato-Cisteína Ligase/metabolismo , Heme Oxigenase-1/genética , Heme Oxigenase-1/metabolismo , Células Hep G2 , Humanos , Proteína 1 Associada a ECH Semelhante a Kelch/genética , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , NADH NADPH Oxirredutases/genética , NADH NADPH Oxirredutases/metabolismo , Fator 2 Relacionado a NF-E2/agonistas , Fator 2 Relacionado a NF-E2/metabolismo , Oxidantes/antagonistas & inibidores , Oxidantes/farmacologia , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , terc-Butil Hidroperóxido/antagonistas & inibidores , terc-Butil Hidroperóxido/farmacologia
13.
Eur J Pharmacol ; 856: 172416, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31132359

RESUMO

Flavonoids are natural active components. They distribute widely in edible plants with high activity of anti-inflammation. Inhibition of cyclooxygenase-2(COX-2) was determined by real-time fluorescent quantitative olymerase chain reaction (RTFQ-PCR). And structure characteristics of flavonoids for COX-2 inhibition were mainly analyzed by a quantitative structure activity relationship (QSAR) model. Descriptors such as SMR_VSA5, vsurf_DD12, reactive were the top three important independent variables to COX-2 mRNA inhibiton in RAW264.7. Low SMR_VSA5 value meant a lower molecular refractivity resulting in a lower COX-2 mRNA inhibition. High vsurf_DD12 value related to poor molecular balance and showed profound adverse to COX-2 mRNA inhibition. Reactive group in this paper referred to C2-C3 double bond contributed negatively to COX-2 mRNA inhibition. Glycosidic and C3-OH substitutions may lower SMR_VSA5 value. It indicated that flavanones such as hesperetin, naringenin, liquiritigenin were efficient to repress COX-2 mRNA and they were potential anti-inflammatory natural products. Further, substitution with a glucopyranosyl at C-6 resulted in a poorer molecule balance than that at C-8 and a lower COX-2 mRNA inhibiton accordingly. This may expain why orientin and vitexin exhibited better anti-inflammatory activity than their isomers homoorientin and isovitexin. Also, methoxyl groups at C-4' may also be a favorable flavonoid structural characteristic for COX-2 mRNA inhibiton. These results provide valuable information on understanding the high anti-inflammatory activity of flavonoids.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Ciclo-Oxigenase 2/genética , Flavonoides/farmacologia , Lipopolissacarídeos/farmacologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Animais , Anti-Inflamatórios não Esteroides/química , Sobrevivência Celular/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Flavonoides/química , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Macrófagos/citologia , Camundongos , Relação Quantitativa Estrutura-Atividade , Células RAW 264.7 , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
14.
Molecules ; 24(9)2019 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-31035631

RESUMO

P-glycoprotein (P-gp) serves as a therapeutic target for the development of inhibitors to overcome multidrug resistance (MDR) in cancer cells. In order to enhance the uptake of chemotherapy drugs, larger amounts of P-gp inhibitors are required. Besides several chemically synthesized P-gp inhibitors, flavonoids as P-gp inhibitors are being investigated, with their advantages including abundance in our daily diet and a low toxicity. The cytotoxicity of daunorubicin (as a substrate of P-gp) to KB/MDR1 cells and the parental KB cells was measured in the presence or absence of flavonoids. A two-dimensional quantitative structure-activity relationship (2D-QSAR) model was built with a high cross-validation coefficient (Q2) value of 0.829. Descriptors including vsurf_DW23, E_sol, Dipole and vsurf_G were determined to be related to the inhibitory activity of flavonoids. The lack of 2,3-double bond, 3'-OH, 4'-OH and the increased number of methoxylated substitutions were shown to be beneficial for the inhibition of P-gp. These results are important for the screening of flavonoids for inhibitory activity on P-gp.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/antagonistas & inibidores , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/química , Flavonoides/química , Flavonoides/farmacologia , Relação Quantitativa Estrutura-Atividade , Sobrevivência Celular , Relação Dose-Resposta a Droga , Humanos , Células KB , Modelos Moleculares , Conformação Molecular , Ligação Proteica
15.
Mol Nutr Food Res ; : e1801363, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31116489

RESUMO

SCOPE: The prebiotic regulation of the gut microbiota is a promising strategy to induce protective humoral and mucosal immune responses. The potential immune-improving effects of pectin oligosaccharides (POS) in healthy mice and the potential mechanism mediated by specific intestinal bacteria are investigated. METHODS AND RESULTS: POS is prepared using a hydrogen-peroxide-assisted degradation. Mice that consumed diets containing POS are tested for microbial community shifts, short-chain fatty acids (SCFAs), and immunoglobulin (Ig) production using quantitative real-time polymerase chain reaction, gas chromatography, and ELISA kits. Pearson's correlation analyses are performed between Ig production and specific intestinal bacteria or SCFAs. POS treatment significantly improves the growth of healthy mice. Moreover, 4-week POS administration results in a profound change in intestinal microbial composition and a significantly higher fecal concentration of acetate, which leads to substantial increases of the levels of fecal secretory immunoglobulin A and serum IgG. CONCLUSIONS: The results suggest that the inclusion of POS in a diet can increase Ig production and optimize the composition of the gut microbiota. A significant correlation is observed between changes in Ig production and specific intestinal bacteria or acetate, providing insight into the mechanism of POS as a potential immune-enhancing supplement.

16.
Pathogens ; 8(2)2019 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-31117307

RESUMO

Lactobacillus plantarum are amongst the diversified lactic acid bacteria (LAB) species which are being utilized abundantly in the food industry. Numerous L. plantarum strains have been reported to produce several antimicrobial compounds. Diacetyl, hydrogen peroxide, organic acids, as well as bacteriocins can also be exemplified by a variable spectrum of actions. The current study was intended to conduct the screening and characterization of antimicrobial prospective of L. plantarum from traditional Inner Mongolian fermented hard cheese. Foodborne pathogens, Salmonella typhimurium, Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus, were examined by using the Oxford cup technique and the mixed culture inhibition assays. The resulting analyses disclosed that L. plantarum KLDS1.0344 indicated broad antimicrobial spectrum against all selected pathogens as compared to other LAB used in this study. Additionally, the decrement of the pathogen population was observed up to 3.47 logs in mixed culture inhibition assays. L. plantarum KLDS 1.0344 acid production was recorded up to 71.8 ± 3.59 °D in mixed culture while antimicrobial particles released in cell free supernatants demonstrated bacteriocin-like characteristics showing substantial pH stability (2.0-6.0), proteolytic enzyme reduced the antibacterial activity (15.2 ± 0.6 mm-20.4 ± 0.8 mm), heat stability (20 min at 120 °C) against selected pathogens. Moreover, the spectrum range of antimicrobial peptides after the partial purification was decreased as compared to the crude bacteriocin-like compound. The SDS-PAGE analysis showed the molecular weight range of partially purified bacteriocin from 12 to 45 kDa. After analyzing the obtained data from the current experimentation showed that the capability of L. plantarum KLDS 1.0344 to oppose the pathogen growth in vitro relies on the occurrence of organic acids along with bacteriocin-like compounds proving L. plantarum KLDS 1.0344 as a potentially appropriate candidate as an alternative bio-control agent against foodborne pathogens.

17.
J Agric Food Chem ; 67(22): 6377-6386, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-31117499

RESUMO

A lipo-dipeptide (C13-lysine-arginine, C13-KR) was designed as a potential emulsifier with good emulsifying properties under acidic condition. Compared with two traditional emulsifiers (whey protein isolate and Tween 80), C13-KR emulsion had the minimum mean size but the highest zeta potential (around +100 mV). Moreover, C13-KR emulsion showed better stability against environmental stresses, such as high salt concentrations and high temperature. The C13-KR particles had the fastest move rate around 400 Hz when it attained an equilibrium state. Furthermore, C13-KR emulsifier could sharply reduce the interfacial tension and had the lowest tension value at the oil/water interface. The interfacial tension of C13-KR emulsifier was only 3.6 mN/m (0.5% w/v). In conclusion, the lipo-dipeptide C13-KR could be considered as an emulsifier to produce emulsion under acidic condition.


Assuntos
Dipeptídeos/química , Emulsificantes/química , Estabilidade de Medicamentos , Temperatura Alta , Tamanho da Partícula , Polissorbatos/química , Tensão Superficial , Proteínas do Soro do Leite/química
18.
Molecules ; 24(10)2019 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-31109085

RESUMO

Apart from non-enzymatic browning, polyphenol oxidase (PPO) also plays a role in the browning reaction of orange (Citrus sinensis Osbeck) juice, and needs to be inactivated during the processing. In this study, the protein with high PPO activity was purified from orange (Citrus sinensis Osbeck) and inactivated by ultrasonic processing. Fluorescence spectroscopy, circular dichroism (CD) and Dynamic light scattering (DLS) were used to investigate the ultrasonic effect on PPO activity and structural changes on purified PPO. DLS analysis illustrated that ultrasonic processing leads to initial dissociation and final aggregation of the protein. Fluorescence spectroscopy analysis showed the decrease in fluorescence intensity leading to the exposure of Trp residues to the polar environment, thereby causing the disruption of the tertiary structure after ultrasonic processing. Loss of α-helix conformation leading to the reorganization of secondary structure was triggered after the ultrasonic processing, according to CD analysis. Ultrasonic processing could induce aggregation and modification in the tertiary and secondary structure of a protein containing high PPO activity in orange (Citrus sinensis Osbeck), thereby causing inactivation of the enzyme.


Assuntos
Catecol Oxidase/química , Citrus sinensis/química , Proteínas de Plantas/química , Conformação Proteica/efeitos da radiação , Ondas Ultrassônicas , Catecol Oxidase/isolamento & purificação , Catecol Oxidase/metabolismo , Dicroísmo Circular , Citrus sinensis/enzimologia , Ativação Enzimática , Reação de Maillard , Peso Molecular , Tamanho da Partícula , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/metabolismo , Análise Espectral
19.
Food Chem ; 291: 101-109, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31006447

RESUMO

This study was aimed to determine the relationship of flavonoid structures to their affinity for an important efflux transporter, multidrug-resistant associated protein 2 (MRP2). The cellular uptake (CU) of 35 flavonoids was investigated in MRP2 overexpression MDCK/MRP2 cells. Resulting data identified 8 flavonoids as MRP2 substrates based on their high CUMK with MK-571 in MDCK/MRP2 cells. Also, three substrates showed better CUMD in MDCK cells than did CUMRP in MDCK/MRP2 cells. Docking analyses showed a good correlation (R = 0.926, p = 0.003) between efflux-fold of flavonoid substrates and their docking S_scoring with the MRP2 model, indicating consistency between in silico and in vitro approaches. A structure affinity relationship (SAR) study indicated that 3-OH, 5-OH, 6-OH, 3'-OH, and 4'-OCH3 substituents were favourable while, 8-OCH3, 2'-OH, 3'-OCH3, 4'-OH and 5'-OH were unfavourable for flavonoid affinity to MRP2. Our study provides valuable information for dietary application of flavonoids with specific structures for high absorption.


Assuntos
Flavonoides/metabolismo , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Animais , Sítios de Ligação , Sobrevivência Celular/efeitos dos fármacos , Cães , Flavonoides/química , Flavonoides/farmacologia , Ligação de Hidrogênio , Células Madin Darby de Rim Canino , Simulação de Acoplamento Molecular , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Estrutura Terciária de Proteína , Especificidade por Substrato
20.
ACS Appl Mater Interfaces ; 11(15): 14266-14274, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30912642

RESUMO

Although a high-efficiency air filter can be achieved from electrospun nanofabrics, it has been challenging to reduce the pressure drop, increase the filtration capacity, and improve the production rate of the electrospinning process. Here, we report a hierarchically structured all-biomass air filter with high filtration efficiency and low air pressure drop based on applying Pickering emulsions to generate protein-functionalized nanostructures. Specifically, the air filter consists of cellulose nanofibers (CNF)/zein nanoparticles as active fillers prepared from Pickering emulsions and porous structures of microfibers as the frame from wood pulp (WP). The zein-protein-coated nanoparticles, CNF/zein, contribute in multiple ways to improve removal efficiency of the filters. First, the exposed functional groups of zein-protein help to trap air pollutants including toxic gaseous molecules via interaction mechanisms. Second, the nanoparticles with a high surface area promote the capture capability for small particulate pollutants. Meanwhile, the long-micron WP fibers forming a frame with large pores significantly reduce the pressure drop. Via adjusting the component ratios of in the Pickering emulsion, we report an optimized air filter with the high efficiency for capturing both types of pollutants: particulate matter (PM) and chemical gasses such as HCHO and CO, and the extremely low normalized pressure drop, that is, approximately 1/170 of the zein-based nano air filter by electrospinning. This study initiates a cost-effective strategy for forming a hierarchical nano- and microstructure, enabling high efficiency of capturing particulate pollutants of a wide size range and more species. More significantly, this is the first study in which Pickering emulsion is applied as a critical approach with integration of bio- and nano-technology to make high-performance, green air filters.

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