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1.
Foods ; 12(4)2023 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-36832940

RESUMO

Pecan (Carya illinoinensis) nuts are an economically valuable crop native to the United States and Mexico. A proteomic summary from two pecan cultivars at multiple time points was used to compare protein accumulation during pecan kernel development. Patterns of soluble protein accumulation were elucidated using qualitative gel-free and label-free mass-spectrometric proteomic analyses and quantitative (label-free) 2-D gel electrophoresis. Two-dimensional (2-D) gel electrophoresis distinguished a total of 1267 protein spots and shotgun proteomics identified 556 proteins. Rapid overall protein accumulation occurred in mid-September during the transition to the dough stage as the cotyledons enlarge within the kernel. Pecan allergens Car i 1 and Car i 2 were first observed to accumulate during the dough stage in late September. While overall protein accumulation increased, the presence of histones diminished during development. Twelve protein spots accumulated differentially based on 2-D gel analysis in the weeklong interval between the dough stage and the transition into a mature kernel, while eleven protein spots were differentially accumulated between the two cultivars. These results provide a foundation for more focused proteomic analyses of pecans that may be used in the future to identify proteins that are important for desirable traits, such as reduced allergen content, improved polyphenol or lipid content, increased tolerance to salinity, biotic stress, seed hardiness, and seed viability.

2.
Foods ; 10(11)2021 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-34828996

RESUMO

To increase the demand for U.S. farm-raised catfish, five healthy, convenient ready-to-cook products were developed to expand consumers' options beyond basic fresh or frozen fillets. Five new catfish products were produced, consisting of one hundred samples of each, including three size-types of Panko-breaded fish products (strips, center cuts of regular fillets, and center cuts from Delacata fillets) and two marinated products (sriracha and sesame-ginger). The breaded products were to be prepared by baking for convenience over traditional frying methods, while the marinated products were to be microwaved as healthy and convenient products. The nutrient content of the samples was analyzed, including protein, moisture, fat, fiber, ash, and carbohydrate, as well as minerals, amino acid, and fatty acid constituent content, with associated atherogenic index (AI) and thrombogenic index (TI), showing unique differences between the Panko-breaded and marinated products. In addition, a trend was observed showing an increase in moisture, protein, ash, and carbohydrate percentages, and a decrease in lipid content related to the volume-to-surface-area ratio, having the order of strips < standard fillets < Delacata fillets.

3.
Sci Rep ; 11(1): 9209, 2021 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-33911142

RESUMO

In this work, we sequentially extracted water (CSPw)- and alkali (CSPa)-soluble protein fractions from glandless cottonseed. SDS-Gel electrophoresis separated CSPw and CSPa to 8 and 14 dominant polypeptide bands (110-10 kDa), respectively. Liquid chromatography-electrospray ionization-tandem mass spectrometry identified peptide fragments from 336 proteins. While the majority of peptides were identified as belonging to vicilin and legumin storage proteins, peptides from other functional and uncharacterized proteins were also detected. Based on the types (unique peptide count) and relative abundance (normalized total ion current) of the polypeptides detected by mass spectrometry, we found lower levels (abundance) and types of legumin isoforms, but higher levels and more fragments of vicilin-like antimicrobial peptides in glandless samples, compared to glanded samples. Differences in peptide fragment patterns of 2S albumin and oleosin were also observed between glandless and glanded protein samples. These differences might be due to the higher extraction recovery of proteins from glandless cottonseed as proteins from glanded cottonseed tend to be associated with gossypol, reducing extraction efficiency. This work enriches the fundamental knowledge of glandless cottonseed protein composition. For practical considerations, this peptide information will be helpful to allow better understanding of the functional and physicochemical properties of glandless cottonseed protein, and improving the potential for food or feed applications.


Assuntos
Óleo de Sementes de Algodão/isolamento & purificação , Óleo de Sementes de Algodão/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Armazenamento de Sementes/metabolismo , Sementes/metabolismo , Óleo de Sementes de Algodão/química , Proteínas de Plantas/análise , Proteínas de Armazenamento de Sementes/análise , Sementes/química , Leguminas
4.
Int J Mol Sci ; 21(21)2020 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-33158240

RESUMO

Nut-based milks and yogurts are gaining popularity, but may not offer the same benefits as dairy yogurts to consumers. Cashew nuts often cause severe allergic reactions, and cashew nut allergens are stable to several types of processing. To compare its characteristics to dairy yogurt and characterize the effects of fermentation on the Ana o 1-3 cashew nut allergens, a commercial yogurt made from cashew nuts (Cashewgurt) was evaluated for microbiological, physiochemical, and immunological properties. Average counts for lactobacilli and Streptococcus thermophilus were greater than 10 million colony forming units per milliliter, indicating the capacity to provide a health benefit. Cashewgurt pH and viscosity values were comparable to cow milk yogurts, and it was off white in color. SDS-PAGE analysis indicated a clear reduction in Ana o 1 and 2, and immuno-assay with polyclonal anti-cashew IgG antibody and cashew-allergic IgE indicated an overall reduction in allergen content. In contrast, SDS-PAGE, mass spectrometry, immunoblot, and ELISA all revealed that Ana o 3 was relatively unaffected by the fermentation process. In conclusion, Ana o 1 and Ana o 2 are sensitive to degradation, while Ana o 3 survives lactic acid bacterial fermentation during yogurt production. The analysis presented here indicates that cashew nut yogurt is not suitable for those with cashew nut allergy.


Assuntos
Alérgenos/análise , Anacardium/química , Iogurte/microbiologia , Alérgenos/imunologia , Sequência de Aminoácidos , Anacardium/imunologia , Carga Bacteriana , Bifidobacterium/classificação , Bifidobacterium/isolamento & purificação , Fenômenos Químicos , Comércio , Enterobacteriaceae/classificação , Enterobacteriaceae/isolamento & purificação , Análise de Alimentos/métodos , Hipersensibilidade Alimentar/imunologia , Humanos , Concentração de Íons de Hidrogênio , Lactobacillus/classificação , Lactobacillus/isolamento & purificação , Hipersensibilidade a Noz/imunologia , Nozes/imunologia , Nozes/microbiologia , Probióticos/análise , Streptococcus thermophilus/classificação , Streptococcus thermophilus/isolamento & purificação , Viscosidade , Iogurte/análise
5.
Toxicol Rep ; 6: 736-744, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31388501

RESUMO

Food allergies represent a substantial medical liability and preventing accidental exposure to food allergens requires constant attention. Allergic reaction to cashew nuts is frequently serious, and the small 2S albumin, Ana o 3, is an immuno-dominant cashew allergen. Ana o 3 is composed of five alpha helices, contains 2 subunits linked by cysteine disulfide bonds, and remains soluble even after extensive heating of cashew nuts. The stability and solubility properties of Ana o 3 make it an excellent target for diagnostic and detection methods and tools. In this work, a monoclonal antibody, designated 2H5, aimed at amino acids 39-54 within helices I and II of the small subunit of Ana o 3 was developed that recognizes both recombinant and native Ana o 3 and is cashew specific in ELISA experiments. The KD against the targeted amino-acid sequence was found to be approximately 7.0 × 10-6 mg/ml (3.3 nM), while the KD against the native protein was found to be approximately 1.2 × 10-3 mg/ml (92 nM). The 2H5 monoclonal anti-Ana o 3 antibody can distinguish between native and recombinant proteins and represents a useful reagent for the study of antibody cashew-allergen interactions and may enable the development of cashew-specific diagnostic tools that can be used to prevent accidental cashew allergen exposures.

6.
Food Chem ; 241: 372-379, 2018 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-28958542

RESUMO

Cashew and pistachio allergies are considered a serious health problem. Previous studies have shown that thermal processing, pressurization and enzymatic hydrolysis may reduce the allergenic properties of food by changing the protein structure. This study assesses the allergenic properties of cashew and pistachio after thermal treatment (boiling and autoclaving), with or without pressure (autoclaving), and multiple enzymatic treatments under sonication, by SDS-PAGE, western blot and ELISA, with serum IgE of allergic individuals, and mass spectroscopy. Autoclaving and enzymatic hydrolysis under sonication separately induced a measurable reduction in the IgE binding properties of pastes made from treated cashew and pistachio nuts. These treatments were more effective with pistachio allergens. However, heat combined with enzymatic digestion was necessary to markedly lower IgE binding to cashew allergens. The findings identify highly effective simultaneous processing conditions to reduce or even abolish the allergenic potency of cashew and pistachio.


Assuntos
Alérgenos/metabolismo , Anacardium , Pistacia , Humanos , Hidrólise , Imunoglobulina E
7.
Food Sci Nutr ; 5(6): 1065-1071, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-29188033

RESUMO

Whole peanut or cashew extracts are usually used in immunotherapy. Reducing major allergen(s) in the extracts may lessen their side effects. Three methods were evaluated to reduce major allergens in peanut extracts: (1) p-aminobenzamidine; (2) magnetic agarose beads; and (3) extraction of a commercial peanut flour at pH 7, respectively. The first two methods were also used to reduce major allergens in cashew extracts. After treatments, samples were evaluated by SDS-PAGE. pABA-treated samples were also analyzed for IgE binding in western blot. We found that the methods resulted in peanut extracts lacking detectable Ara h 1 but containing Ara h 2/6 and cashew extract lacking Ana o 1/2, but containing Ana o 3. Consequently, reduced IgE binding was observed. We conclude that the methods are useful for producing peanut or cashew extract with little Ara h 1 or Ana o 1/2.

8.
Food Sci Nutr ; 5(5): 981-988, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28948015

RESUMO

The objective of this study was to chemically characterize both channel and hybrid catfish parts including heads, frames, viscera, skin, and fillet trimming mince. Triplicate samples of channel and hybrid catfish byproduct parts were obtained from a large commercial catfish processor and analyzed for percent moisture, lipid, protein, ash, and amino acid and fatty acid profiles were determined. The content of the off-flavor compounds, 2-methylisoborneol (MIB) and geosmin were also determined. The lipid content of samples were 13.6% and 10.0% for channel and hybrid skins, 17.7% and 21.4% for channel and hybrid viscera, 20.0% and 19.1% for channel and hybrid frames, and 9.7% and 9.3% for channel and hybrid heads. The protein content of samples ranged from a high of 22.8% for channel catfish skins, to a low of 13.4% for channel frames. Low levels of geosmin, <1 ppb, were detected in the byproduct samples, while no MIB was detected. Palmitic, oleic, and linoleic acid comprised approximately 80% of the fatty acids in the byproduct tissues. The amino acid profiles indicated that the catfish mince had high levels of lysine and methionine and other essential amino acids. Results from this study will be used in the development of new value-added products from catfish byproducts.

9.
PLoS One ; 12(8): e0182260, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28767688

RESUMO

Cockroach allergens can lead to serious allergy and asthma symptoms. Termites are evolutionarily related to cockroaches, cohabitate in human dwellings, and represent an increasing pest problem in the United States. The Formosan subterranean termite (Coptotermes formosanus) is one of the most common species in the southern United States. Several assays were used to determine if C. formosanus termite proteins cross-react with cockroach allergens. Expressed sequence tag and genomic sequencing results were searched for homology to cockroach allergens using BLAST 2.2.21 software. Whole termite extracts were analyzed by mass-spectrometry, immunoassay with IgG and scFv antibodies to cockroach allergens, and human IgE from serum samples of cockroach allergic patients. Expressed sequence tag and genomic sequencing results indicate greater than 60% similarity between predicted termite proteins and German and American cockroach allergens, including Bla g 2/Per a 2, Bla g 3/Per a 3, Bla g 5, Bla g 6/Per a 6, Bla g 7/Per a 7, Bla g 8, Per a 9, and Per a 10. Peptides from whole termite extract were matched to those of the tropomyosin (Bla g 7), arginine kinase (Per a 9), and myosin (Bla g 8) cockroach allergens by mass-spectrometry. Immunoblot and ELISA testing revealed cross-reaction between several proteins with IgG and IgE antibodies to cockroach allergens. Several termite proteins, including the hemocyanin and tropomyosin orthologs of Blag 3 and Bla g 7, were shown to crossreact with cockroach allergens. This work presents support for the hypothesis that termite proteins may act as allergens and the findings could be applied to future allergen characterization, epitope analysis, and clinical studies.


Assuntos
Alérgenos/imunologia , Baratas/imunologia , Imunoglobulinas/metabolismo , Isópteros/imunologia , Alérgenos/genética , Animais , Baratas/genética , Reações Cruzadas , Imunoglobulina A/metabolismo , Imunoglobulina E/metabolismo , Proteínas de Insetos/genética , Proteínas de Insetos/imunologia , Isópteros/genética , Homologia de Sequência do Ácido Nucleico , Estados Unidos
10.
J Sci Food Agric ; 97(2): 469-478, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27060570

RESUMO

BACKGROUND: High antioxidant content and keen marketing have increased blueberry demand and increased local production which in turn mandates new uses for abundant harvests. Pilot scale processes were employed to investigate the anthocyanidin profiles, qualitative volatile compositions, and sensorial attributes in not-from-concentrate (NFC) 'Tifblue' rabbiteye blueberry juices. RESULTS: Processing prior to pasteurization generally resulted in increased L* and hue angle color, while a* , b* , and C* decreased. After 4 months pasteurized storage, non-clarified juice (NCP) lost 73.8% of total volatiles compared with 70.9% in clarified juice (CJP). There was a total anthocyanidin decrease of 84.5% and 85.5% after 4 months storage in NCP and CJP, respectively. Storage itself resulted in only 14.2% and 7.2% anthocyanidin loss after pasteurization in NCP and CJP. Storage significantly affected nine flavor properties in juices; however, there were no significant differences in the blueberry, strawberry, purple grape, floral, sweet aroma, or sweet tastes between processed and stored juices. CONCLUSIONS: NFC pasteurized blueberry juices maintained desirable flavors even though highly significant volatile and anthocyanidin losses occurred through processing. Maintenance of color and flavor indicate that NFC juices could have an advantage over more abusive methods often used in commercial juice operations. © 2016 Society of Chemical Industry.


Assuntos
Antocianinas/análise , Mirtilos Azuis (Planta)/química , Manipulação de Alimentos/métodos , Sucos de Frutas e Vegetais/análise , Frutas/química , Pasteurização , Compostos Orgânicos Voláteis/análise , Cor , Qualidade dos Alimentos , Humanos , Odorantes , Fenóis/análise , Especificidade da Espécie , Paladar
11.
J Agric Food Chem ; 65(2): 411-420, 2017 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-27966914

RESUMO

Raw and roasted cashew nut extracts were evaluated for protein modifications by mass spectrometry. Independent modifications on the Arg-111 residue of Ana o 3 were observed in roasted but not raw cashew nuts. The mass changes of 72.0064 or 53.9529 Da are consistent with the formation of carboxyethyl and hydroimidazolone modifications at the Arg-111 residue. These same modifications were observed in Ana o 3 purified from roasted but not raw cashew nuts, albeit at a relatively low occurrence. Circular dichroism indicated that Ana o 3 purified from raw and roasted cashew nuts had similar secondary structure, and dynamic light scattering analysis indicated there was no observable difference in particle size. The stability of Ana o 3 purified from raw and roasted cashew nuts to trypsin was similar in the absence of or following treatment with a reducing agent. Only minor differences in IgE binding to Ana o 3 were observed by ELISA among a cohort of cashew-allergic patient sera.


Assuntos
Anacardium/química , Antígenos de Plantas/química , Arginina/química , Manipulação de Alimentos/métodos , Proteínas de Plantas/química , Antígenos de Plantas/isolamento & purificação , Antígenos de Plantas/metabolismo , Dicroísmo Circular , Difusão Dinâmica da Luz , Ensaio de Imunoadsorção Enzimática , Calefação , Humanos , Imidazóis/química , Soros Imunes , Imunoglobulina E/metabolismo , Hipersensibilidade a Noz/imunologia , Nozes/química , Tamanho da Partícula , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/metabolismo , Conformação Proteica , Tripsina/química
12.
Mycobiology ; 44(3): 162-170, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27790067

RESUMO

In this paper, we demonstrate the ability of Arabidopsis thaliana to detect different mixtures of volatile organic compounds (VOCs) emitted by the common indoor fungus, Aspergillus versicolor, and demonstrate the potential usage of the plant as a bioindicator to monitor fungal VOCs in indoor air. We evaluated the volatile production of Aspergillus versicolor strains SRRC 108 (NRRL 3449) and SRRC 2559 (ATCC 32662) grown on nutrient rich fungal medium, and grown under conditions to mimic the substrate encountered in the built environment where fungi would typically grow indoors (moist wallboard and ceiling tiles). Using headspace solid phase microextraction/gas chromatography-mass spectrometry, we analyzed VOC profiles of the two strains. The most abundant compound produced by both strains on all three media was 1-octen-3-ol. Strain SRRC 2559 made several terpenes not detected from strain SRRC 108. Using a split-plate bioassay, we grew Arabidopsis thaliana in a shared atmosphere with VOCs from the two strains of Aspergillus versicolor grown on yeast extract sucrose medium. The VOCs emitted by SRRC 2559 had an adverse impact on seed germination and plant growth. Chemical standards of individual VOCs from the Aspergillus versicolor mixture (2-methyl-1-butanol, 3-methyl-1-butanol, 1-octen-3-ol, limonene, and ß-farnesene), and ß-caryophyllene were tested one by one in seed germination and vegetative plant growth assays. The most inhibitory compound to both seed germination and plant growth was 1-octen-3-ol. Our data suggest that Arabidopsis is a useful model for monitoring indoor air quality as it is sensitive to naturally emitted fungal volatile mixtures as well as to chemical standards of individual compounds, and it exhibits relatively quick concentration- and duration-dependent responses.

13.
Toxicol Rep ; 3: 244-251, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28959544

RESUMO

Cashew nuts are an increasingly common cause of food allergy. We compare the soluble protein profile of cashew nuts following heating. SDS-PAGE indicate that heating can alter the solubility of cashew nut proteins. The 11S legumin, Ana o 2, dominates the soluble protein content in ready to eat and mildly heated cashew nuts. However, we found that in dark-roasted cashew nuts, the soluble protein profile shifts and the 2S albumin Ana o 3 composes up to 40% of the soluble protein. Analysis of trypsin-treated extracts by LC/MS/MS indicate changes in the relative number and intensity of peptides. The relative cumulative intensity of the 5 most commonly observed Ana o 1 and 2 peptides are altered by heating, while those of the 5 most commonly observed Ana o 3 peptides remaine relatively constant. ELISA experiments indicate that there is a decrease in rabbit IgG and human serum IgE binding to soluble cashew proteins following heating. Our findings indicate that heating can alter the solubility of cashew allergens, resulting in altered IgE binding. Our results support the use of both Ana o 2 and Ana o 3 as potential cashew allergen diagnostic targets.

14.
Food Sci Nutr ; 3(4): 273-83, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26288719

RESUMO

Ara h 1 is a major peanut allergen. Processing-induced modifications may modulate the allergenic potency of Ara h 1. Carboxymethyl lysine (CML) modifications are a commonly described nonenzymatic modification on food proteins. In the current study, we tested the ability of digestive and endolysosomal proteases to cleave CML-modified and unmodified Ara h 1 peptides. Mass spectrometric analyses of the digested peptides demonstrate that carboxymethylation of lysine residues renders these peptides refractory to trypsin digestion. We did not detect observable differences in the simulated gastric fluid or endolysosomal digestion between the parental and CML-modified peptides. One of the tested peptides contains a lysine residue previously shown to be CML modified laying in a previously mapped linear IgE epitope, but we did not observe a difference in IgE binding between the modified and parental peptides. Our findings suggest a molecular mechanism for the increased resistance of peanut allergens modified by thermal processing, such as Ara h 1, to digestion in intestinal fluid after heating and could help explain how food processing-induced modifications may lead to more potent food allergens by acting to protect intact IgE epitopes from digestion by proteases targeting lysine residues.

15.
Data Brief ; 4: 302-7, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26217806

RESUMO

Covalent labeling of solvent exposed amino acid residues using chemical reagents/crosslinkers followed by mass spectrometric analysis can be used to determine the solvent accessible amino acids of a protein. A variety of chemical reagents containing cleavable bonds were developed to label abundantly found lysine residues on the surface of protein. To achieve efficient separation of labeled peptides prior to mass spectrometric analysis, magnetic nanoparticles can be decorated with amino acid reactive functional groups and utilized for quick recovery of labeled peptides. [1] In this work, iron oxide magnetic nanoparticles (Fe3O4 MNPs) were synthesized by thermal decomposition method and coated with silica (SiO2@Fe3O4 MNPs) by reverse micro emulsion approach. The Fe3O4 MNPs and SiO2@Fe3O4 MNPs were characterized by TEM and XRD. The SiO2@Fe3O4 MNPs were further coated with amine groups and conjugated to N-hydroxysuccinimidyl (NHS) ester groups via a cleavable ester bond. Fluorescence based qualitative analysis of ester linked NHS ester modified SiO2@Fe3O4 MNPs was performed to confirm the presence of NHS ester group. The active NHS ester sites on the surface of SiO2@Fe3O4 MNPs were determined by depletion approach and found to be 694 active sites per 1 mg of SiO2@Fe3O4 MNPs. Free amine groups of a small peptide, ACTH (4-11) were labeled by ester linked, NHS ester modified SiO2@Fe3O4 MNPs under physiological conditions. Superparamagnetic nature of SiO2@Fe3O4 MNPs allowed quick and efficient magnetic separation of labeled peptides from the solution. The ester bond was further cleaved to separate labeled peptides followed by mass spectrometric analysis. The ester linked, NHS ester modified SiO2@Fe3O4 MNPs introduced a mass shift of 115.09 Da on amine groups of ACTH (4-11), which was confirmed by mass spectrometry.

16.
Molecules ; 20(6): 11236-56, 2015 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-26096432

RESUMO

Countless hours of research and studies on triazine, phosphonate, and their combination have provided insightful information into their flame retardant properties on polymeric systems. However, a limited number of studies shed light on the mechanism of flame retardancy of their combination on cotton fabrics. The purpose of this research is to gain an understanding of the thermal degradation process of two triazine-phosphonate derivatives on cotton fabric. The investigation included the preparation of diethyl 4,6-dichloro-1,3,5-triazin-2-ylphosphonate (TPN1) and dimethyl (4,6-dichloro-1,3,5-triazin-2-yloxy) methyl phosphonate (TPN3), their application on fabric materials, and the studies of their thermal degradation mechanism. The studies examined chemical components in both solid and gas phases by using attenuated total reflection infrared (ATR-IR) spectroscopy, thermogravimetric analysis coupled with Fourier transform infrared (TGA-FTIR) spectroscopy, and 31P solid state nuclear magnetic resonance (31P solid state NMR), in addition to the computational studies of bond dissociation energy (BDE). Despite a few differences in their decomposition, TPN1 and TPN3 produce one common major product that is believed to help reduce the flammability of the fabric.


Assuntos
Fibra de Algodão , Retardadores de Chama , Organofosfonatos/química , Triazinas/química , Espectroscopia de Ressonância Magnética , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
17.
Anal Biochem ; 484: 18-20, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-25983234

RESUMO

To study the solvent-exposed lysine residues of peptides/proteins, we previously reported disulfide-linked N-hydroxysuccinimide ester-modified silica-coated iron oxide magnetic nanoparticles (NHS-SS-SiO2@Fe3O4 MNPs). The presence of a disulfide bond in the linker limits the use of disulfide reducing agent during protein digestion and allows unwanted disulfide formation between the MNPs and protein. In the current work, the disulfide bond was replaced with a cleavable ester group to synthesize NHS ester-modified SiO2@Fe3O4 MNPs. Use of the cleavable ester group provides an improved method for protein labeling and allows the use of disulfide reducing agents during protein digestion.


Assuntos
Aminas/química , Lactoglobulinas/química , Nanopartículas de Magnetita/química , Peptídeos/química , Proteínas/química , Soroalbumina Bovina/química , Solventes/química , Sequência de Aminoácidos , Animais , Bovinos , Ésteres , Dados de Sequência Molecular , Dióxido de Silício/química , Coloração e Rotulagem , Temperatura
18.
J Food Sci ; 80(4): S818-27, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25816898

RESUMO

Six cultivars of southern highbush (SHB) and rabbiteye (RE) blueberry samples were harvested on 2 different dates. Each treatment combination was pressed 2 times for repeated measures. Fresh juice was characterized for 18 flavor/taste/feeling factor attributes by a descriptive flavor panel. Each sample was measured for sugars, acids, anthocyanidins, Folin-Ciocalteu, soluble solids (BRIX), titratable acidity (TA), and antioxidant capacity (ORACFL ). Flavors were correlated with the composition and physicochemical data. Blueberry flavor correlated with 3 parameters, and negatively correlated with 2. Strawberry correlated with oxalic acid and negatively correlated with sucrose and quinic acid. Sweet aroma correlated with oxalic and citric acid, but negatively correlated with sucrose, quinic, and total acids. Sweet taste correlated with 11 parameters, including the anthocyanidins; and negatively correlated with 3 parameters. Neither bitter nor astringent correlated with any of the antioxidant parameters, but both correlated with total acids. Sour correlated with total acids and TA, while negatively correlating with pH and BRIX:TA. Throat burn correlated with total acids and TA. Principal component analysis negatively related blueberry, sweet aroma, and sweet to sour, bitter, astringent, tongue tingle, and tongue numbness. The information in this component was related to pH, TA, and BRIX:TA ratio. Another principal component related the nonblueberry fruit flavors to BRIX. This PC, also divided the SHB berries from the RE. This work shows that the impact of juice composition on flavor is very complicated and that estimating flavor with physicochemical parameters is complicated by the composition of the juice.


Assuntos
Ácidos/análise , Antocianinas/análise , Mirtilos Azuis (Planta) , Frutas/química , Preparações de Plantas/química , Sacarose/análise , Paladar , Antioxidantes/análise , Bebidas/análise , Carboidratos/análise , Humanos , Concentração de Íons de Hidrogênio , Odorantes , Língua
19.
PLoS One ; 9(9): e106403, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25203006

RESUMO

Momordica charantia is often called bitter melon, bitter gourd or bitter squash because its fruit has a bitter taste. The fruit has been widely used as vegetable and herbal medicine. Alpha-eleostearic acid is the major fatty acid in the seeds, but little is known about its biosynthesis. As an initial step towards understanding the biochemical mechanism of fatty acid accumulation in bitter melon seeds, this study focused on a soluble phosphatidic acid phosphatase (PAP, 3-sn-phosphatidate phosphohydrolase, EC 3.1.3.4) that hydrolyzes the phosphomonoester bond in phosphatidate yielding diacylglycerol and P(i). PAPs are typically categorized into two subfamilies: Mg(2+)-dependent soluble PAP and Mg(2+)-independent membrane-associated PAP. We report here the partial purification and characterization of an Mg(2+)-independent PAP activity from developing cotyledons of bitter melon. PAP protein was partially purified by successive centrifugation and UNOsphere Q and S columns from the soluble extract. PAP activity was optimized at pH 6.5 and 53-60 °C and unaffected by up to 0.3 mM MgCl2. The K(m) and Vmax values for dioleoyl-phosphatidic acid were 595.4 µM and 104.9 ηkat/mg of protein, respectively. PAP activity was inhibited by NaF, Na(3)VO(4), Triton X-100, FeSO4 and CuSO4, but stimulated by MnSO4, ZnSO4 and Co(NO3)2. In-gel activity assay and mass spectrometry showed that PAP activity was copurified with a number of other proteins. This study suggests that PAP protein is probably associated with other proteins in bitter melon seeds and that a new class of PAP exists as a soluble and Mg(2+)-independent enzyme in plants.


Assuntos
Momordica charantia/enzimologia , Fosfatidato Fosfatase/química , Fosfatidato Fosfatase/metabolismo , Cotilédone/citologia , Cotilédone/enzimologia , Cotilédone/crescimento & desenvolvimento , Inibidores Enzimáticos/farmacologia , Concentração de Íons de Hidrogênio , Espaço Intracelular/metabolismo , Cinética , Magnésio/metabolismo , Momordica charantia/citologia , Momordica charantia/crescimento & desenvolvimento , Fosfatidato Fosfatase/antagonistas & inibidores , Proteínas de Plantas/metabolismo , Transporte Proteico , Solubilidade , Temperatura
20.
J Agric Food Chem ; 62(28): 6746-55, 2014 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-24926808

RESUMO

Cashew nut and other nut allergies can result in serious and sometimes life-threatening reactions. Linear and conformational epitopes within food allergens are important for immunoglobulin E (IgE) binding. Methods that disrupt allergen structure can lower IgE binding and lessen the likelihood of food allergy reactions. Previous structural and biochemical data have indicated that 2S albumins from tree nuts and peanuts are potent allergens, and that their structures are sensitive to strong reducing agents such as dithiothreitol. This study demonstrates that the generally regarded as safe (GRAS) compound sodium sulfite effectively disrupted the structure of the cashew 2S albumin, Ana o 3, in a temperature-dependent manner. This study also showed that sulfite is effective at disrupting the disulfide bond within the cashew legumin, Ana o 2. Immunoblotting and ELISA demonstrated that the binding of cashew proteins by rabbit IgG or IgE from cashew-allergic patients was markedly lowered following treatment with sodium sulfite and heating. The results indicate that incorporation of sodium sulfite, or other food grade reagents with similar redox potential, may be useful processing methods to lower or eliminate IgE binding to food allergens.


Assuntos
Alérgenos/imunologia , Anacardium/imunologia , Temperatura Alta , Imunoglobulina E/metabolismo , Sulfitos/farmacologia , Albuminas 2S de Plantas/química , Albuminas 2S de Plantas/imunologia , Adolescente , Adulto , Alérgenos/química , Alérgenos/efeitos dos fármacos , Sequência de Aminoácidos , Animais , Antígenos de Plantas/química , Antígenos de Plantas/efeitos dos fármacos , Antígenos de Plantas/imunologia , Criança , Hipersensibilidade Alimentar/imunologia , Humanos , Imunoglobulina G/metabolismo , Pessoa de Meia-Idade , Dados de Sequência Molecular , Estrutura Molecular , Nozes/imunologia , Proteínas de Plantas/química , Proteínas de Plantas/efeitos dos fármacos , Proteínas de Plantas/imunologia , Coelhos
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