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1.
Food Chem ; 366: 130557, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34284195

RESUMO

Diacylglycerol (DAG) is commonly used as fat substitute in food manufacture due to its functional properties, but DAG has poor emulsification and oxidation stability, which limits its wide application in food industry. In this work, fluorescence quenching data and thermodynamic parameters were analyzed to investigate the interaction mechanism between l-theanine (L-Th) and ß-lactoglobulin (ß-LG). DAG emulsion was prepared by using ß-lactoglobulin-theanine (ß-LG-Th) as surface stabilizer, and its emulsification and oxidation stability were evaluated. The results showed that the hydrophobic interaction played an important role on the conjugate of ß-LG and L-Th due to the negative values for ΔG, positive values for ΔH and ΔS at pH 4.0, pH 6.0 and pH 8.0. The DAG has been better embedded by using ß-LG-Th as surface stabilizer, and the droplet size was about 0.2 µm to 1.5 µm when the pH was 6.0, the ratio of L-Th to ß-LG was 1:1. ß-LG-Th as surface stabilizer for DAG can increase the ζ-potential and emulsion index, make the emulsion droplet size distribution more uniform. The l-theanine was better to be used to improve the emulsification stability and antioxidant capacity of DAG by binding ß-LG as surface stabilizer.


Assuntos
Antioxidantes , Lactoglobulinas , Diglicerídeos , Emulsões , Glutamatos , Interações Hidrofóbicas e Hidrofílicas
2.
Food Chem ; 367: 130655, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34371277

RESUMO

Interactions between the dimeric form of ß-lactoglobulin and vanillic acid were investigated at pH 7.2, using a variety of spectroscopic techniques and molecular dynamics (MD) simulations. FTIR and CD studies showed alterations in the secondary structure of the protein upon its interaction with the ligand. Fluorescence measurements indicated that the dimeric complex with the phenolic acid produced a large dissociation constant (KD) compared to the monomeric counterpart at acidic pH (part A of this series). Stoichiometry of 1:1 was identified for the ß-lactoglobulin-vanillic acid complex by Job plot analysis at neutral pH suggesting two ligand molecules can participate in binding with the dimer. Molecular docking and MD simulations suggested that the top-ranked binding sites of the ligand were located at the entrance of each ß-barrel structure of the dimer. These simulations also allowed identification of the contribution of water molecules, in the form of protein-water-ligand bridging interactions, to the complexes.


Assuntos
Lactoglobulinas , Simulação de Dinâmica Molecular , Sítios de Ligação , Concentração de Íons de Hidrogênio , Lactoglobulinas/metabolismo , Simulação de Acoplamento Molecular , Ligação Proteica , Ácido Vanílico
3.
Food Chem ; 372: 131304, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34655825

RESUMO

Sweet potato leaf polyphenols (SPLPs) have shown potential health benefits in the food and pharmaceutical industries. Nowadays, consumption of SPLPs from animal feeds to foodstuff is becoming a trend worldwide. However, the application of SPLPs is limited by their low bioavailability and stability. ß-lactoglobulin (ßlg), a highly regarded whey protein, can interact with SPLPs at the molecular level to form reversible or irreversible nanocomplexes (NCs). Consequently, the functional properties and final quality of SPLPs are directly modified. In this review, the composition and structure of SPLPs and ßlg, as well as methods of molecular complexation and mechanisms of formation of SPLPsßlgNCs, are revisited. The modified functionalities of SPLPsßlgNCs, especially protein conformational structures, antioxidant activity, solubility, thermal stability, emulsifying, and gelling properties including allergenic potential, digestibility, and practical applications are discussed for SPLPs future development.


Assuntos
Ipomoea batatas , Polifenóis , Animais , Antioxidantes , Lactoglobulinas , Extratos Vegetais , Folhas de Planta
4.
Food Chem ; 371: 131385, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34808778

RESUMO

The combination of multiple dietary polyphenols may have synergistic beneficial effects. And the beneficial effects can be further improved by the encapsulation of proteins. The interactions of procyanidin B2 (PB2) and/or dihydromyricetin (DMY) with ß-lactoglobulin (ß-LG) were investigated using multi-spectroscopic techniques and molecular docking. The structural change of ß-LG in the presence of PB2 and/or DMY was demonstrated by dynamic light scattering, Fourier transform infrared spectroscopy and circular dichroism spectroscopy. Response surface analysis was used to optimize the synergistic antioxidant activity between PB2 and DMY. Besides, the antioxidant activity, stability, in vitro digestion and cytotoxicity of PB2 and DMY in the binary and ternary systems were investigated. These studies will elucidate the interaction mechanism of PB2 and/or DMY with ß-LG. The research results can provide theoretical support for the development of functional foods and beverages with synergistic activity, improved stability and bioaccessibility, thereby promoting human health and preventing diseases.


Assuntos
Lactoglobulinas , Polifenóis , Antioxidantes , Digestão , Humanos , Simulação de Acoplamento Molecular , Espectroscopia de Infravermelho com Transformada de Fourier
5.
J Colloid Interface Sci ; 606(Pt 2): 1673-1683, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34534835

RESUMO

HYPOTHESIS: Although protein adsorption at an interface is very common and important in biology and biotechnology, it is still not fully understood - mainly due to the intricate balance of forces that ultimately control it. In food processing (and medicine), controlling and manipulating protein adsorption, as well as avoiding protein adsorption (biofilm formation or membrane fouling) by the production of protein-resistant surfaces is of substantial interest. A major factor conferring resistance towards protein adsorption to a surface is the presence of tightly bound water molecules, as is the case in oligo ethylene glycol (OEG)-terminated self-assembled monolayers (SAMs). Due to strong attractive protein-protein and protein-surface interactions observed in systems containing trivalent salt ions, we hypothesize that these conditions may lead to a breakdown of protein resistance in OEG SAMs. EXPERIMENTS: We studied the adsorption behavior of BLG in the presence of a lanthanum(III) chloride (LaCl3) at concentrations of 0, 0.1, 0.8 and 5.0 mM on normally protein resistant triethylene glycol-termianted (EG3) SAMs on a gold surface. We used quartz-crystal microbalance with dissipation (QCM-D) and neutron reflectivity (NR) to characterize the morphology of the interfacial region of the SAM. FINDINGS: We demonstrate that the protein resistance of the EG3 SAM breaks down beyond a threshold salt concentration c∗ and mirrors the bulk behaviour of this system, showing reduced adsorption beyond a second critical salt concentration c∗∗. These results demonstrate for the first time the controlled switching of the protein-resistant properties of this type of SAM by the addition of trivalent salt.


Assuntos
Etilenoglicol , Lactoglobulinas , Adsorção , Ouro , Propriedades de Superfície , Água
6.
Food Chem ; 368: 130820, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34416488

RESUMO

Two commercially available food grade fungal protease preparations (Fungal Protease 31,000 and Fungal Protease 60000) were found to hydrolyse bovine acid whey proteins but left the beta-lactoglobulin (ß-Lg) intact under the processing conditions used. Comparative analysis before and after hydrolysis of bovine acid whey, by 1D- and 2D-PAGE, RP-HPLC and intact-mass mass spectrometry showed that the ß-Lg remains intact and in high yield after hydrolysis by the fungal proteases. The ß-Lg could be separated from the whey protein peptide hydrolysate by ultrafiltration. Subjecting whey fraction to hydrolysis with the fungal protease preparations provides a procedure, under relatively mild conditions, to generate a highly enriched ß-Lg fraction. ß-Lg is recognised as a valued material in the food, pharmaceutical and cosmetic industries due to its properties such as gelling and foaming. The enriched ß-Lg preparation would also have application in areas such as nanoencapsulation.


Assuntos
Lactoglobulinas , Leite , Animais , Bovinos , Hidrólise , Proteínas do Leite , Peptídeo Hidrolases , Soro do Leite , Proteínas do Soro do Leite
7.
Food Chem ; 372: 131226, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34627095

RESUMO

The effects of high hydrostatic pressure (HHP) on the conformation and immunoreactivity of bovine ß-lactoglobulin (BLG) were studied. BLG was treated under 100-600 MPa at the temperature of 20-60 °C. The immunoglobulin E (IgE) binding ability of BLG decreased when the pressure increased from 0.1 to 200 MPa. However, the IgE binding increased with the increase in pressure from 200 to 400 MPa, followed by a gradual decrease until a pressure of 600 MPa. The IgE binding ability continuously decreased with an increase in pressure at 60 °C. The conformation of HHP-treated BLG was evaluated using fluorescence spectroscopy, circular dichroism spectroscopy and molecular dynamics (MD) simulation. Increasing the temperature and pressure promoted the unfolding of BLG, causing the disappearance of some α-helixes and some ß-sheets. Based on ELISA analysis, it was revealed that HHP-termperature treatment altered the immunoreactivity of BLG by altering the structures and conformational states of BLG.


Assuntos
Imunoglobulina E , Lactoglobulinas , Animais , Bovinos , Ensaio de Imunoadsorção Enzimática , Pressão Hidrostática , Temperatura
8.
J Agric Food Chem ; 69(46): 14004-14012, 2021 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-34761930

RESUMO

The effects of ultrasound combined with glycation (UCG) on the allergenicity and human microbial community of ß-Lg during in vitro digestion were studied by ELISA, cell experiments, and 16S rRNA high-throughput sequencing. UCG modification and subsequent digestion significantly reduced allergenicity. The decrease in the allergenicity of ß-Lg depended not only on the low digestibility of glycated ß-Lg, which led to the decrease of some peptides with complete immunogenicity, but also the masking effect of glycation on allergen epitopes of ß-Lg. Meanwhile, UCG modification and subsequent digestion could alter the structures of intestinal microbiota and the community abundance at phylum, family, and genus levels, such as Bacteroidota, Fusobacteriota, Enterobacteriaceae, Bacteroidaceae, Ruminococcaceae, Bacteroides, and Faecalibacterium. These results show that simulated in vitro digestion of modified ß-Lg reduces allergenicity and alters human intestinal microbiota, which could provide a theoretical basis for studying the relationship between intestinal dysbiosis and cow's milk allergy.


Assuntos
Microbioma Gastrointestinal , Hipersensibilidade a Leite , Alérgenos , Humanos , Imunoglobulina E , Lactoglobulinas , RNA Ribossômico 16S , Ultrassom
9.
Zhongguo Yi Liao Qi Xie Za Zhi ; 45(5): 551-554, 2021 Sep 30.
Artigo em Chinês | MEDLINE | ID: mdl-34628771

RESUMO

OBJECTIVE: To establish an amino acid assay for the determination of ß-lactoglobulin in Anti-HPV biological protein dressing. METHODS: Under acidic conditions, ß-lactoglobulin is hydrolyzed into free amino acids, separated by cation exchange chromatography, and derivatived after ninhydrin column. The chromatogram at 570 nm is collected. The content of ß-lactoglobulin in the sample is indirectly determined by measuring the lysine content obtained by hydrolysis. RESULTS: ß-lactoglobulin has a good linear relationship in the concentration range of 77.28~309.12 µg/mL (y=5.060x+4.278, r=0.999 7); The recovery rate (n=9) is 100.06%. CONCLUSIONS: The method is simple, specific, accurate and reproducible, which is suitable for the quantitative analysis of ß-lactoglobulin in anti-HPV biological protein dressing.


Assuntos
Aminoácidos , Lactoglobulinas , Bandagens
10.
Analyst ; 146(22): 6808-6814, 2021 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-34647930

RESUMO

Food allergy is an immune system reaction to a particular food, milk being the most common one. ß-Lactoglobulin (ß-Lg) is the main ingredient of milk protein and the main cause of infant milk allergy. On such an occasion, the determination of ß-Lg is very important and the electrochemical sensors are a good alternative for this purpose since they are sensitive, selective and inexpensive. In this work, an electrochemical aptasensor was fabricated for the quantitative detection of ß-Lg in hypoallergenic formula (HF) milk. A tri-functional hairpin (HP) was designed, which was composed of an aptamer sequence, a nicking site and a DNA sequence (T1). In the absence of ß-Lg, the aptamer part hybridized with T1 to form a stable stem-loop structure. However, in the presence of ß-Lg, the capture of the aptamer sequence towards ß-Lg caused the reconstruction of HP and thus the nicking sites were exposed. Then, the nicking enzyme was activated and T1 could be released, which bound with the end of the hairpin 1-methylene blue (HP1-MB)/HP2-MB conjugation on the Au nanoparticle (AuNP) modified electrode surface. Thus, the insulating property of the electrode was enhanced and the current response of MB decreased, which built the quantitative basis for ß-Lg detection. In this way, the proposed aptasensor exhibited a wide linear range of 0.01-100 ng mL-1 and a low detection limit of 5.7 pg mL-1. This aptasensor also displayed high selectivity, reproducibility and stability, and became a promising platform for ß-Lg detection in real food samples.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Nanopartículas Metálicas , Alérgenos , Técnicas Eletroquímicas , Ouro , Humanos , Lactoglobulinas , Limite de Detecção , Reprodutibilidade dos Testes
11.
Soft Matter ; 17(37): 8517-8522, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34494060

RESUMO

Electrostatic complexation of negatively charged polysaccharides with ß-lactoglobulin (ß-lg) has been shown to bolster the protein films at oil/water interfaces thereby improving emulsion stability. However, recent sub-phase exchange experiments demonstrated that highly charged polysaccharides such as low methyl-esterified pectin are complementary only if sequentially introduced to a pre-formed interfacial ß-lg film. In this study, results of transient interfacial shear rheology show that, by using high-methylesterified pectins instead, complexes can be formed in pre-mixed solutions with ß-lg at pH 4 that can lead to reinforced protein films at dodecane/water interfaces. Using this one-shot adsorption of such complexes, pectins as well as short chain polysaccharides like homogalacturonan nearly doubled the steady state shear elastic moduli as compared to that of a pure ß-lg film. The lag times of film formation were established to be primarily decided by the charge density and pattern on the polysaccharide. Based on the results from mixed solutions of ß-lg monomers, it is proposed that the polysaccharide at pH 4 strengthens the resulting interfacial layer by concatenating adsorbed ß-lg molecules thereby establishing cross-links in the aqueous phase.


Assuntos
Lactoglobulinas , Pectinas , Adsorção , Emulsões , Concentração de Íons de Hidrogênio , Eletricidade Estática
12.
Molecules ; 26(18)2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34576939

RESUMO

Whey proteins and oligomeric proanthocyanidins have nutritional value and are widely used in combination as food supplements. However, the effect of the interactions between proanthocyanidins and whey proteins on their stability has not been studied in depth. In this work, we aimed to characterize the interactions between ß-Lactoglobulin (ß-LG) and α-lactalbumin (α-LA) and oligomeric proanthocyanidins, including A1, A2, B1, B2, B3, and C1, using multi-spectroscopic and molecular docking methods. Fluorescence spectroscopic data revealed that all of the oligomeric proanthocyanidins quenched the intrinsic fluorescence of ß-LG or α-LA by binding-related fluorescence quenching. Among the six oligomeric proanthocyanidins, A1 showed the strongest affinity for ß-LG (Ka = 2.951 (±0.447) × 104 L∙mol-1) and α-LA (Ka = 1.472 (±0.236) × 105 L∙mol-1) at 297 K. ß-LG/α-LA and proanthocyanidins can spontaneously form complexes, which are mainly induced by hydrophobic interactions, hydrogen bonds, and van der Waals forces. Fourier-transform infrared spectroscopy (FTIR) and circular dichroism spectroscopy showed that the secondary structures of the proteins were rearranged after binding to oligomeric proanthocyanidins. During in vitro gastrointestinal digestion, the recovery rate of A1 and A2 increased with the addition of WPI by 11.90% and 38.43%, respectively. The addition of WPI (molar ratio of 1:1) increased the retention rate of proanthocyanidins A1, A2, B1, B2, B3, and C1 during storage at room temperature by 14.01%, 23.14%, 30.09%, 62.67%, 47.92%, and 60.56%, respectively. These results are helpful for the promotion of protein-proanthocyanidin complexes as functional food ingredients in the food industry.


Assuntos
Proantocianidinas/química , Proteínas do Soro do Leite/química , Dicroísmo Circular , Digestão , Armazenamento de Alimentos , Lactalbumina/química , Lactoglobulinas/química , Simulação de Acoplamento Molecular , Proantocianidinas/metabolismo , Proantocianidinas/farmacocinética , Espectrometria de Fluorescência , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termodinâmica , Proteínas do Soro do Leite/metabolismo
13.
Nutrients ; 13(9)2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34578889

RESUMO

Human clinical trials have shown that a specific partially hydrolyzed 100% whey-based infant formula (pHF-W) reduces AD risk in the first yeast of life. Meta-analyses with a specific pHF-W (pHF-W1) confirm a protective effect while other meta-analyses pooling different pHF-W show conflicting results. Here we investigated the molecular composition and functional properties of the specific pHF-W1 as well as the stability of its manufacturing process over time. This specific pHF-W1 was compared with other pHF-Ws. We used size exclusion chromatography to characterize the peptide molecular weight (MW), a rat basophil degranulation assay to assess the relative level of beta-lactoglobulin (BLG) allergenicity and a preclinical model of oral tolerance induction to test prevention of allergic sensitization. To analyze the exact peptide sequences before and after an HLA binding assay, a mass cytometry approach was used. Peptide size allergenicity and oral tolerance induction were conserved across pHF-W1 batches of production and time. The median MW of the 37 samples of pHF-W1 tested was 800 ± 400 Da. Further oral tolerance induction was observed using 10 different batches of the pHF-W1 with a mean reduction of BLG-specific IgE levels of 0.76 log (95% CI = -0.95; -0.57). When comparing pHF-W1 with three other formulas (pHF-W2 3 and 4), peptide size was not necessarily associated with allergenicity reduction in vitro nor oral tolerance induction in vivo as measured by specific IgE level (p < 0.05 for pHF-W1 and 2 and p = 0.271 and p = 0.189 for pHF-W3 and 4 respectively). Peptide composition showed a limited overlap between the formulas tested ranging from 11.7% to 24.2%. Furthermore nine regions in the BLG sequence were identified as binding HLA-DR. In conclusion, not all pHF-Ws tested have the same peptide size distribution decreased allergenicity and ability to induce oral tolerance. Specific peptides are released during the different processes used by different infant formula producers.


Assuntos
Alérgenos , Fórmulas Infantis/análise , Lactoglobulinas , Hipersensibilidade a Leite , Peptídeos , Proteínas do Soro do Leite , Alérgenos/imunologia , Animais , Cromatografia , Dermatite Atópica , Indústria Alimentícia , Alimentos Formulados , Humanos , Hidrólise , Imunoglobulina E , Lactente , Lactoglobulinas/análise , Lactoglobulinas/imunologia , Hipersensibilidade a Leite/prevenção & controle , Proteínas do Leite , Peso Molecular , Peptídeos/análise , Peptídeos/imunologia , Hidrolisados de Proteína/análise , Hidrolisados de Proteína/imunologia , Ratos Sprague-Dawley , Soro do Leite , Proteínas do Soro do Leite/análise , Proteínas do Soro do Leite/imunologia
14.
J Dairy Sci ; 104(10): 10473-10484, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34334202

RESUMO

Our previous experiments have confirmed that human milk oligosaccharides (HMO) and its main component 2'-fucosyllactose (2'-FL), as prebiotics, could effectively alleviate cow milk allergy by regulating the intestinal microecology. This study intended to further explore the molecular mechanism of HMO regulating intestinal immunity. The results of the allergic mouse model showed that oral administration of 2'-FL or HMO reduced ß-lactoglobulin (ß-LG)-induced serum-specific IgE secretion and mast cell degranulation, while reducing the inflammatory cytokines, TNF-α, IL-4, and IL-6 production and promoting the miR-146a expression. In vitro results further confirmed that 2'-FL or HMO treatment reduced allergen-induced secretion of iNOS, NO, pro-inflammatory cytokines and reactive oxygen species in RAW264.7 cells. At the same time, in contrast to the ß-LG group, 2'-FL dose-dependently inhibited the TLR4/NF-κB inflammatory pathway and upregulated miR-146a expression, and the effect of the 2'-FL mid-dose group was similar to that of the HMO intervention group. In particular, adding miR-146a inhibitors to macrophages attenuated the inhibitory effect of 2'-FL on the expression of TRAF6 and IRAKI in the TLR4 pathway, suggesting that miR-146a might be involved in the immune regulation of 2'-FL. The above results indicated that 2'-FL had a similar effect to HMOs, and its effect of reducing ß-LG allergy might be related to the regulation of miR-146a to inhibit TLR4/NF-κB signaling pathway.


Assuntos
Doenças dos Bovinos , Hipersensibilidade Alimentar , MicroRNAs , Leite Humano , Animais , Bovinos , Modelos Animais de Doenças , Feminino , Hipersensibilidade Alimentar/imunologia , Humanos , Lactoglobulinas , Camundongos , Leite Humano/metabolismo , NF-kappa B/metabolismo , Oligossacarídeos/farmacologia , Transdução de Sinais , Receptor 4 Toll-Like , Trissacarídeos
15.
J Agric Food Chem ; 69(36): 10669-10677, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34463093

RESUMO

Chloroquine (CQ) is a famous medicine for treatment of diseases including malaria and pneumonia caused by COVID-19, but gastrointestinal disorder caused by its oral administration is a great concern. Milk is usually recommended to be taken with CQ to reduce such effect. However, the mechanism underlying this phenomenon remains unknown. Here, we found that ß-lactoglobulin (ß-LG), α-lactalbumin (α-LA), bovine serum albumin (BSA), and lactoferrin (LF) in whey proteins were able to interact with CQ to form complexes as suggested by fluorescence resonance energy transfer (FRET) and molecular docking. Indeed, the crystal structure revealed that ß-LG is bound to CQ through hydrophobic interactions and hydrogen bonding with a ratio of 1:1. Consequently, the formation of these protein-CQ complexes not only reduced the cytotoxicity of chloroquine to the stomach and gut cells but also facilitated its uptake by cells. This work gave an example to understand the relationship between food and drug.


Assuntos
COVID-19 , Cloroquina , COVID-19/tratamento farmacológico , Cloroquina/farmacologia , Humanos , Lactalbumina , Lactoglobulinas , Proteínas do Leite , Simulação de Acoplamento Molecular , SARS-CoV-2 , Proteínas do Soro do Leite
16.
Phys Chem Chem Phys ; 23(32): 17536-17544, 2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34369530

RESUMO

Water, being an active participant in most of the biophysical processes, is important to trace how protein solvation changes as its conformation evolves in the presence of solutes or co-solvents. In this study, we investigate how the secondary structures of two diverse proteins - lysozyme and ß-lactoglobulin - change in the aqueous mixtures of two alcohols - ethanol and 2,2,2-trifluoroethanol (TFE) using circular dichroism measurements. We observe that these alcohols change the secondary structures of these proteins and the changes are protein-specific. Subsequently, we measure the collective solvation dynamics of these two proteins both in the absence and in the presence of alcohols by measuring the frequency-dependent absorption coefficient (α(ν)) in the THz (0.1-1.2 THz) frequency domain. The alcohol-water mixtures exhibit a non-ideal behaviour with the highest absorption difference (Δα) obtained at Xalcohol = 0.2. The protein solvation in the presence of the alcohols shows an oscillating behaviour in which Δαprotein changes with Xalcohol. Such an oscillatory behaviour of protein solvation results from a delicate interplay between the protein-water, protein-alcohol and water-alcohol associations. We attempt to correlate the various structural conformations of the proteins with the associated solvation.


Assuntos
Etanol/química , Lactoglobulinas/química , Muramidase/química , Trifluoretanol/química , Água/química , Animais , Bovinos , Galinhas , Conformação Proteica , Estrutura Secundária de Proteína , Solubilidade , Espectroscopia Terahertz
17.
J Vet Med Sci ; 83(10): 1509-1512, 2021 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-34373420

RESUMO

We investigated the IgE reactivity to crude and purified milk antigens in the sera of 112 dogs with cutaneous adverse food reactions (CAFRs). Of the 112 dogs, 33 (29%) had specific IgE for crude milk antigens. In the dogs with milk-specific IgE, IgE reactivity to casein, bovine serum albumin (BSA), α-lactalbumin, ß-lactoglobulin, and bovine IgG were 81%, 85%, 39%, 27%, and 35%, respectively. Casein and BSA may be important allergens in dogs with CAFRs. Some canine vaccines contain casein hydrolysate as a stabilizer and the pooled serum with anti-casein IgE showed IgE reactivity to the vaccines containing it. Information about IgE reactivity to casein in dogs with CAFRs could be useful for predicting adverse reactions to the vaccines including casein hydrolysate.


Assuntos
Doenças dos Bovinos , Doenças do Cão , Hipersensibilidade a Leite , Alérgenos , Animais , Bovinos , Cães , Imunoglobulina E , Lactoglobulinas , Leite , Hipersensibilidade a Leite/veterinária
18.
Nutrients ; 13(6)2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34203636

RESUMO

BACKGROUND: beta-lactoglobulin (BLG) is one of the major cow's milk proteins and the most abundant allergen in whey. Heating is a common technologic treatment applied during milk transformational processes. Maillardation of BLG in the presence of reducing sugars and elevated temperatures may influence its antigenicity and allergenicity. PRIMARY OBJECTIVE: to analyze and identify lactosylation sites by capillary electrophoresis mass spectrometry (CE-MS). SECONDARY OBJECTIVE: to assess the effect of lactosylated BLG on antigenicity and degranulation of mast cells. METHODS: BLG was lactosylated at pH 7, a water activity (aw) of 0.43, and a temperature of 65 °C using a molar ratio BLG:lactose of 1:1 by incubating for 0, 3, 8, 16 or 24 h. For the determination of the effect on antibody-binding capacity of lactosylated BLG, an ELISA was performed. For the assessment of degranulation of the cell-line RBL-hεIa-2B12 transfected with the human α-chain, Fcε receptor type 1 (FcεRI) was used. RESULTS: BLG showed saturated lactosylation between 8 and 16 incubation hours in our experimental setup. Initial stage lactosylation sites L1 (N-terminus)-K47, K60, K75, K77, K91, K138 and K141-have been identified using CE-MS. Lactosylated BLG showed a significant reduction of both the IgG binding (p = 0.0001) as well as degranulation of anti-BLG IgE-sensitized RBL-hεIa-2B12 cells (p < 0.0001). CONCLUSIONS AND CLINICAL RELEVANCE: this study shows that lactosylation of BLG decreases both the antigenicity and degranulation of mast cells and can therefore be a promising approach for reducing allergenicity of cow's milk allergens provided that the process is well-controlled.


Assuntos
Lactoglobulinas/análise , Hipersensibilidade a Leite , Leite/química , Alérgenos/análise , Animais , Bovinos , Feminino , Humanos , Imunoglobulina E/análise , Imunoglobulina G , Lactose/análise , Reação de Maillard , Mastócitos , Proteínas do Leite/análise , Soro do Leite , Proteínas do Soro do Leite/análise
19.
Nanoscale ; 13(29): 12534-12545, 2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34263899

RESUMO

ß-Lactoglobulin amyloid fibrils are bio-colloids of high interest in many fields (e.g. water purification, cell growth, drug delivery and sensing). While the mechanical properties of pure amyloid fibril gels meet the needs of some applications, mechanical fragility often hinders a wider usage basin. In this work, we present a simple and sustainable approach for reinforcing amyloid fibril hydrogels and aerogels, upon the diffusion of polysaccharides (low-acetylated Gellan Gum and κ-carrageenan) inside their mesh. The formed hybrid materials show enhanced resistance upon compression, without any loss of the exquisite surface reactivity of the amyloid fibrils. The proposed approach can pave the way for designing composite materials that are both highly functional and environmentally friendly.


Assuntos
Amiloide , Hidrogéis , Carragenina , Sistemas de Liberação de Medicamentos , Lactoglobulinas
20.
Food Chem ; 364: 130030, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34198035

RESUMO

Aggregation of bovine ß-lactoglobulin is affected easily by external factors. In this study, effects of metal ions combining with temperature on aggregation of ß-lactoglobulin were explored. The conformational characteristics of aggregates were detected by environment scanning electron microscope, CD spectrum and free sulfhydryl group, respectively. Digestive and immunological characteristics were assessed by simulated digestion in vitro and ELISA respectively. The results showed that the morphology of ß-lactoglobulin aggregates became more amorphous in Cu2+ and Mg2+ treated samples and more constricted in Zu2+-induced protein. Among them, Cu2+ altered the secondary structure of ß-lactoglobulin aggregates and free sulfhydryl content most as well as that in gastric digestion. However, all ion-treated groups had similar digestive stability in intestinal digestion. Specially, Ca2+ and Mg2+ made the antigenicity and potential allergenicity of ß-lactoglobulin aggregates decrease, which helps us understand the role of metal ions in immunological characteristics.


Assuntos
Alérgenos , Lactoglobulinas , Animais , Bovinos , Calefação , Íons , Estrutura Secundária de Proteína
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