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1.
Food Chem ; 305: 125433, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31499293

RESUMO

Native high methoxy citrus pectin (NP) was de-esterified by pectin methyl esterase to produce modified pectins [MP (42, 37, and 33)] having different degrees of esterification. Complex coacervation between a pea protein isolate (PPI) and each pectin was investigated as a function of pH (8.0-1.5) and mixing ratio (1:1-30:1, PPI-pectin). Complex formation was found to be optimal for biopolymer-mixing ratios of 8:1, 8:1, 25:1 and 25:1 for PPI complexed with NP, MP42, MP37 and MP33, respectively, at pHs 3.6, 3.5, 3.9 and 3.9. And, the critical pHs associated with complex formation (accessed by turbidity) was found to shift significantly to higher pHs as the degree of esterification of the pectin decreased, whereas the shift in the pH corresponding to their initial interactions was minimal with degree of esterification. Complexation of PPI with NP and MP42 greatly improved the protein solubility.

2.
Food Chem ; 302: 125343, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31430630

RESUMO

Pectin was extracted from blueberry powder as water soluble fraction (WSF), rich in branched regions, and chelator soluble fraction (CSF), linear, with strong negative charge. Binding of pectins with three anthocyanin standards (malvidin-3-glucoside; M3G, cyanidin-3-glucoside; C3G, and delphinidin-3-glucoside; D3G) and blueberry extract (BBE) were used. Without blueberry pectin, M3G was the most stable followed by C3G, whereas D3G completely disappeared after gastrointestinal digestion. CSF prevented M3G and C3G degradation more than WSF, the in vitro stability was highest with CSF and C3G. Increased stability of anthocyanins after simulated gastrointestinal digestion suggests that anthocyanins can be transported to colon where gut microbiota actively produce anthocyanin metabolites. The amount of bound anthocyanins that interacted with blueberry pectin increased as the number of hydroxyl groups increased on anthocyanins. Hydrogen bonding in addition to electrostatic interaction contribute to stability of pectin-anthocyanins interaction at pH 4.0 and contribute to stability under gastrointestinal simulation.


Assuntos
Antocianinas/química , Antocianinas/farmacocinética , Mirtilos Azuis (Planta)/química , Pectinas/química , Antocianinas/metabolismo , Digestão , Glucosídeos/química , Glucosídeos/metabolismo , Glucosídeos/farmacocinética , Ligações de Hidrogênio , Concentração de Íons de Hidrogênio , Pectinas/metabolismo , Pectinas/farmacocinética , Extratos Vegetais/química , Eletricidade Estática
3.
Nutrients ; 11(9)2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31443365

RESUMO

Development of obesity-associated comorbidities is related to chronic inflammation, which has been linked to gut microbiota dysbiosis. Thus, modulating gut microbiota composition could have positive effects for metabolic disorders, supporting the use of probiotics as potential therapeutics in vivo, which may be enhanced by a microencapsulation technique. Here we investigated the effects of non-encapsulated or pectin-encapsulated probiotic supplementation (Lactobacillus paracasei subsp. paracasei L. casei W8®; L. casei W8) on gut microbiota composition and metabolic profile in high-fat (HF) diet-fed rats. Four male Wistar rat groups (n = 8/group) were fed 10% low-fat, 45% HF, or HF with non-encapsulated or encapsulated L. casei W8 (4 × 107 CFU/g diet) diet for seven weeks. Microbiota composition, intestinal integrity, inflammatory profiles, and glucose tolerance were assessed. Non-encapsulated and pectin-encapsulated probiotic supplementation positively modulated gut microbiota composition in HF-fed male rats. These changes were associated with improvements in gut barrier functions and local and systemic inflammation by non-encapsulated probiotics and improvement in glucose tolerance by encapsulated probiotic treatment. Thus, these findings suggest the potential of using oral non-encapsulated or encapsulated probiotic supplementation to ameliorate obesity-associated metabolic abnormalities.

4.
J Food Sci ; 2018 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-30462831

RESUMO

Pectins from highbush blueberry powder were sequentially solubilized in water, chelator, and sodium carbonate solvents and precipitated (ADF.WSF, ADF.CSF, and ADF.NSF) or not precipitated in ethanol (DF.WSF, DF.CSF, and DF.NSF) before dialysis and freeze-drying. Alcohol precipitation more effectively removed bound anthocyanins and low molar mass pectins from water- and chelator soluble fractions than dialysis alone. Blueberry water soluble fractions were high methoxyl pectins, rich in neutral sugars (36 to 38 mol%), and had high molar mass (7.01 × 105 to 2.71 × 106  g/mol). Blueberry chelator soluble fractions were low methoxyl pectins and rich in uronic acids (90 to 92 mol%) which were more linear and less branched structure than other fractions or commercial citrus pectin. The molar mass ranged from 1.59 × 106 to 2.06 × 106  g/mol. Water- and chelator soluble fractions exhibited pseudoplastic behavior (n < 1) at 1% dispersion. Blueberry sodium carbonate soluble fractions were rich in protein (18%) and neutral sugars (42 to 28 mol%), and had low molar mass (1.08 × 105 to 1.27 × 105  g/mol). Blueberry pectins have desirable physico-chemical properties for use as functional ingredients in food or beverages. PRACTICAL APPLICATION: Alcohol precipitation effectively removed anthocyanins from the pectin. The characterization data provided the benefits of blueberry pectin as a functional ingredient. This study can be used by food or product developers who are interested in pectin from blueberries or other berry products.

5.
Carbohydr Polym ; 179: 282-289, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29111053

RESUMO

A rheological study was carried out to evaluate formulations of test dispersions and gels of high methoxyl pectins (HTHMP) obtained at different conditions from husk tomato waste (Physalis ixocarpa Brot.). The effect of extraction agent (hydrochloric acid or citric acid), blanching time (10 or 15min) and extraction time (15, 20 or 25min) on the rheology of the tested samples was evaluated. Flow behavior and activation energy were evaluated on the test dispersions, while (Ea) frequency sweeps, temperature sweep, creep-recovery test and penetration test were performed on the gels. HTHMP dispersions showed shear thinning flow behavior, while showing a good fit to Cross model. Extraction agent, blanching time and extraction time did not have effect on Cross parameters (ηz, η∞, C, and m). Ea decreased as blanching time and extraction time increased. Frequency sweeps revealed high dependence on frequency for both G' and G", while temperature sweeps (25- 95°C) showed thermostable husk tomato pectin gels. Hydrocloric acid (HCl) extracted pectin gels showed stronger structure than citric acid (CA) gels.

6.
J Food Sci ; 82(7): 1594-1601, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28585703

RESUMO

Husk tomato (Physalis ixocarpa Brot. var. Rendidora) waste was evaluated as a source of specialized pectin, and pectin extracted from this waste was characterized physicochemically. Fruit was blanched for 10 or 15 min and extracted in 0.1 N HCl for 15 to 25 min. Extracted pectin was subjected to physicochemical analysis. For all extraction conditions, the percentage of anhydrogalacturonic acid exceeded 60%, indicating that husk tomato was a good source of pectin. The degree of esterification of pectin molecules was 63% to 91%. The amount of extracted pectin decreased with increasing extraction time. The apparent viscosity of husk tomato pectin showed the characteristic behavior of pseudoplastic fluids. Neutral sugars were identified, and the amounts of 6 sugars (fucose, rhamnose, arabinose, galactose, glucose, and xylose) were quantified. Sugars identified in husk tomato pectin and present in the Rhamnogalacturonan I region, arabinose, galactose, and rhamnose suggest a highly branched structure, which will influence its future applications. Molecular weight values were 542 to 699 kDa, exceeding molecular weight values reported for commercial citrus pectins from 134 to 480 kDa. The extraction process significantly (P < 0.05) influenced the physicochemical properties of pectin. Up to 19.8% from the total amount of pectin in the husk tomato was extracted by 10 min of blanching and 20 min of a more heat treatment. Our findings indicate that husk tomato can be a good alternative source of pectin having highly distinctive physicochemical characteristics.


Assuntos
Fenômenos Químicos , Pectinas/análise , Physalis/química , Arabinose/análise , Esterificação , Manipulação de Alimentos , Frutas/química , Galactose/análise , Peso Molecular , Extratos Vegetais/análise , Ramnose/análise , Ácidos Urônicos/análise , Viscosidade
7.
J Sci Food Agric ; 97(11): 3720-3726, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28111766

RESUMO

BACKGROUND: The effect of the addition of hydroxypropyl methylcellulose (HPMC) on the textural properties of low-fat tofu was investigated. Three fat levels (240, 100 and 30 g kg-1 ) were used to make tofu, which were identified as C (full-fat tofu), L1 and L2. HPMC (5 g kg-1 ) was added to soymilk to prepare control and low-fat tofu, designated as CH, L1H and L2H. RESULTS: Soymilk with a lower fat level had a lower viscosity: 143 (C), 100 (L1) and 42 (L2) cP. The addition of HPMC increased the viscosity of all types of soymilk, particularly in L2H (107 cP). With fat reduction, tofu syneresis increased from 19% (C) to 29% (L2), although syneresis of L2H recovered to 19%, which is similar to high-fat control tofu. Decreased fat resulted in a lower firmness in L2 (0.67 N) compared to control (0.78 N). Firmness increased to 1.08 N in L2H tofu, whereas the firmness of CH tofu was 0.63 N. All types of tofu showed a denser, well-connected and cross-linking structure when HPMC was added, especially in L2H tofu. CONCLUSION: HPMC improved the texture of the low-fat tofu by creating a harder texture and reducing syneresis. HPMC is an effective fat replacer for lower fat soymilk. © 2017 Society of Chemical Industry.


Assuntos
Substitutos da Gordura/análise , Derivados da Hipromelose/análise , Alimentos de Soja/análise , Gorduras/análise , Dureza , Leite de Soja/química , Viscosidade
8.
J Sci Food Agric ; 97(7): 2057-2067, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27569539

RESUMO

BACKGROUND: Preventing post-harvest waste of Palmyra palm (Borassus aethiopum Mart.) fruits is possible by recovery of pectin as a value-added ingredient. Extraction conditions on yield and functionality of Palmyra palm pectin was determined at different temperatures and pH values with 30 min extraction time. RESULTS: Palmyra palm fruits contain more than 650 g kg-1 galacturonic acid and produce soft gels with sucrose in acidic media despite a high degree of acetylation (∼5%). Mechanical deformation of pectin gel was similar when extracted at pH 2.5 and 70 °C or under natural pH at room temperature or 70 °C. Pectins isolated at pH 7 exhibited comparable gel softness (G'/G″) with commercial pectin. Palm pectins also showed emulsifying activity greater than 50%, attributed to high protein content of 8 g 100 g-1 . For pectins extracted at pH near 5.2-5.5, molar mass ranged from 3.00 to 3.38 × 105 g mol-1 ; intrinsic viscosity ranged from 218 to 297 mL g-1 ; arabinose was the main neutral sugar; ζ-potential ranged from -23 to -25 mV. CONCLUSION: Palm fruit offers an inexpensive raw material to extract pectin in environmentally friendly and economical way and yield a pectin with unique gelling, viscosifying and emulsifying properties. © 2016 Society of Chemical Industry.


Assuntos
Arecaceae/química , Frutas/química , Pectinas/química , Extratos Vegetais/química , Biotecnologia , Concentração de Íons de Hidrogênio , Peso Molecular , Pectinas/isolamento & purificação , Extratos Vegetais/isolamento & purificação , Temperatura Ambiente , Viscosidade
9.
J Sci Food Agric ; 95(5): 1000-7, 2015 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-24924689

RESUMO

BACKGROUND: Tofu made from low-fat soy flour is a nutritional food for consumers and economically benefits the food processor. However, low-fat tofu has poor textural quality, especially insufficient firmness. Stepwise heating (heating at 75 °C, followed by holding at 95 °C) of full-fat soymilk increases gel properties. Therefore we evaluated the two-step heating of low-fat soymilk to improve tofu texture. RESULTS: The denaturation enthalpy and temperature of ß-conglycinin and glycinin were higher in low-fat tofu compared to high-fat tofu. The viscosity of low-fat soymilk and texture of tofu by one-step heating were weaker than full-fat soymilk and tofu. However, the two-step heating increased free sulfhydryl groups and viscosity of low-fat soymilk to a value higher or similar to conventional soymilk. The syneresis of low-fat tofu was reduced about 30% and hardness was higher (131.0 N) by the two-step process compared to one-step heating of full-fat tofu (101.4 N) by the one-step process. The microstructure of low-fat tofu became finer, denser and more homogeneous by the two-step heat process. CONCLUSION: Low-fat tofu produced by denaturing the two major soy proteins separately had improved textural qualities similar to full-fat tofu as a result of increased hydrophobic interactions between denatured protein molecules.


Assuntos
Dieta com Restrição de Gorduras , Manipulação de Alimentos , Qualidade dos Alimentos , Proteínas de Vegetais Comestíveis/química , Alimentos de Soja/análise , Leite de Soja/química , Proteínas de Soja/química , Antígenos de Plantas/química , Fenômenos Químicos , Cisteína/análise , Cisteína/química , Cistina/análise , Cistina/química , Géis , Globulinas/química , Dureza , Temperatura Alta , Humanos , Interações Hidrofóbicas e Hidrofílicas , Fenômenos Mecânicos , Desnaturação Proteica , República da Coreia , Proteínas de Armazenamento de Sementes/química , Propriedades de Superfície , Viscosidade
10.
Ultrason Sonochem ; 21(1): 43-9, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23871416

RESUMO

An efficient cold-mechanical/sonic-assisted extraction technique was developed for extraction of genipin from genipap (Genipa americana) peel. Ultrasound assisted extraction (285 W, 24 kHz) was performed at 5, 10 and 15 °C for 5, 10 and 15 min. After cold-extraction, genipin was separated from pectin and proteins by aid of fungal pectinesterase. The maximum yield of non-cross-linked genipin was 7.85±0.33 mg/g, at 10 °C for 15 min by means of ultrasound extraction. The protein amount in extracts decreased in all samples. If mechanical process is combined with ultrasound assisted extraction the yield is increased by 8 times after the pectinesterase-assisted polyelectrolyte complex formation between pectic polysaccharides and proteins, avoiding the typical cross-linking of genipin. This novel process is viable to obtain non-cross-linked genipin, to be used as a natural colorant and cross-linker in the food and biotechnological industries.


Assuntos
Hidrolases de Éster Carboxílico/metabolismo , Fracionamento Químico/métodos , Temperatura Baixa , Iridoides/isolamento & purificação , Fenômenos Mecânicos , Rubiaceae/química , Aspergillus/enzimologia , Química Verde
11.
Plant Physiol ; 163(3): 1203-17, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24092888

RESUMO

The function of a putative galacturonosyltransferase from Arabidopsis (Arabidopsis thaliana; At1g02720; GALACTURONOSYLTRANSFERASE-LIKE5 [AtGATL5]) was studied using a combination of molecular genetic, chemical, and immunological approaches. AtGATL5 is expressed in all plant tissues, with highest expression levels in siliques 7 DPA. Furthermore, its expression is positively regulated by several transcription factors that are known to regulate seed coat mucilage production. AtGATL5 is localized in both endoplasmic reticulum and Golgi, in comparison with marker proteins resident to these subcellular compartments. A transfer DNA insertion in the AtGATL5 gene generates seed coat epidermal cell defects both in mucilage synthesis and cell adhesion. Transformation of atgatl5-1 mutants with the wild-type AtGATL5 gene results in the complementation of all morphological phenotypes. Compositional analyses of the mucilage isolated from the atgatl5-1 mutant demonstrated that galacturonic acid and rhamnose contents are decreased significantly in atgatl5-1 compared with wild-type mucilage. No changes in structure were observed between soluble mucilage isolated from wild-type and mutant seeds, except that the molecular weight of the mutant mucilage increased 63% compared with that of the wild type. These data provide evidence that AtGATL5 might function in the regulation of the final size of the mucilage rhamnogalacturonan I.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Mucilagem Vegetal/metabolismo , Sementes/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Retículo Endoplasmático/metabolismo , Regulação da Expressão Gênica de Plantas , Teste de Complementação Genética , Complexo de Golgi/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Ácidos Hexurônicos/metabolismo , Hibridização In Situ , Microscopia Confocal , Microscopia Eletrônica de Varredura , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , Pectinas/metabolismo , Mucilagem Vegetal/análise , Plantas Geneticamente Modificadas , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Ramnose/metabolismo , Sementes/genética , Sementes/ultraestrutura , Transcriptoma
12.
Carbohydr Polym ; 98(1): 276-81, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-23987345

RESUMO

The methyl and hydroxypropyl substituents in hydroxypropyl methylcellulose (HPMC) affect the resulting gel properties. These substituents in five HPMC gels were characterized using Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, small-amplitude oscillatory shear measurements, and differential scanning calorimetry (DSC). In FT-IR spectra, the most intense peak appeared at 1053 cm(-1), denoting the presence of the glucose ring. The ratio of peak intensities at 1452 cm(-1), which represents -C-H absorptions, and at 1053 cm(-1) (I1452/I1053) and percent methylation from gas chromatography exhibited a linear association (r(2)=0.6296). The broadening of the Raman spectra indicated that the relative crystallinity of HPMC decreases with increasing hydroxypropyl contents. DSC showed no linear relationship between the percent hydroxypropylation in HPMC and the percentage of free water in an HPMC gel. Small-amplitude oscillatory shear measurements revealed that the formation of an entanglements networks and/or weak gel depends on substituent contents.


Assuntos
Metilcelulose/análogos & derivados , Reologia , Absorção , Derivados da Hipromelose , Metilcelulose/química , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman
13.
Colloids Surf B Biointerfaces ; 104: 116-21, 2013 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-23298595

RESUMO

The physical and chemical properties of commercial low methoxyl citrus pectins, CP 28 and CP 55, and a pectinmethylesterase (PME) charge modified citrus pectin (MP 38) were compared, and the differences in ability to encapsulate indomethacin in hydrogel beads was determined at 0.5 or 1.0% (w/v) indomethacin ratio, and 100, 200 or 300 mM CaCl(2) solution. In order to investigate the drug release characteristics, indomethacin loaded dried hydrogel beads were immersed in simulated gastric fluids (pH 1.2) for 2h, followed by immersing in simulated intestinal fluids (pH 7.4) for 3h. Pectin type was highly significant (p<0.0001) for encapsulation efficiency and in vitro release assay. Encapsulation efficiency was also highly affected (p<0.0001) by indomethacin ratio and CaCl(2) concentration. The accumulative release rate of indomethacin from pectin hydrogel bead was less than 15% in simulated gastro-intestinal fluids. MP 38 beads showed significantly higher entrapment efficiency and lower release rate than beads formed from CP 28 or CP 55. MP 38 hydrogel formulated with 300 mM CaCl(2) and 0.5% indomethacin ratio showed the highest entrapment efficiency. These studies suggest that charge modification of pectin improves encapsulation efficiency of drugs for colon targeted drug delivery system through oral administration.


Assuntos
Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Indometacina/química , Pectinas/química , Cloreto de Cálcio/química , Concentração de Íons de Hidrogênio , Tamanho da Partícula , Solubilidade , Propriedades de Superfície
14.
Carbohydr Polym ; 89(4): 1244-9, 2012 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-24750938

RESUMO

Laccase, an oxidative enzyme, was used to catalyze the hetero and homo covalent conjugation between ferulic acid in sugar beet pectin (SBP) and tyrosine in heated ß-lactoglobulin (H_BLG). The conjugation of SBP and H_BLG was confirmed by peak position using size exclusion chromatography, multi angle laser light scattering, refractive index, and UV detection. H_BLG, pre-treated with laccase, eluted at an earlier volume with greater UV280 absorbance than non-laccase treated dispersions. Tyrosine decreased in H_BLG that contained laccase treated SBP samples. Heat enhanced exposure of tyrosine in BLG and improved conjugation with SBP by laccase. H_BLG·SBP conjugates with laccase had improved solubility than laccase untreated dispersions at pH values near the isoelectric point of BLG.


Assuntos
Beta vulgaris/química , Lacase/química , Lactoglobulinas/química , Pectinas/química , Temperatura Alta , Solubilidade
15.
J Sci Food Agric ; 92(1): 78-83, 2012 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-21815155

RESUMO

BACKGROUND: Pale broiler breast meat is a defect in commercial production operations. The incidence of pale broiler breast meat was examined in two commercial processing plants which had average growth rates of 59 g day(-1) and 46 g day(-1) and final average weights of 3.36 kg and 1.93 kg. Color measurements of dorsal and ventral surfaces and pH were completed to evaluate the impact of selection for growth on meat water-holding capacity. RESULTS: L* greater than 60 were observed in 57% of broilers selected for greater yield and 26% of slower growing broilers. Average L* between 10 growers was significantly different (P = 0.001). Pearson's correlation coefficients for pH and L* were - 0.51 and - 0.27 for the faster growing broilers and slower growing broilers, respectively. The Pearson correlation coefficients between water-holding capacity and L* and pH was - 0.35 and 0.42, respectively. There was a higher correlation between production factors (age, weight and grower) and a* and b* than L* for ventral surface measurements. CONCLUSION: Breasts from broilers selected for faster growth tend to have lighter color. Weak correlation with water-holding capacity suggests that quality remains the same and light color is probably related to other factors.


Assuntos
Água Corporal , Peso Corporal , Galinhas/crescimento & desenvolvimento , Cor , Carne/análise , Músculo Esquelético , Animais , Manipulação de Alimentos , Humanos , Concentração de Íons de Hidrogênio
16.
J Agric Food Chem ; 59(24): 13181-7, 2011 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-22010637

RESUMO

Chickens from a randomly bred genetic line were segregated into high and low growth rates and high and low water-holding capacities (WHCs). The objective of this study was to identify protein markers associated with slow and fast growth rates and low and high WHCs from water-soluble protein (WSP) and crude myofibrillar protein (CMP) extracts of chicken breast muscle. Proteins were fractionated using two-dimensional electrophoresis, and a total of 22 protein spots were selected, excised, and analyzed by in-gel tryptic digestion and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Proteins expressed in extracts from slow and fast growth rates and low and high WHCs included metabolic enzymes, such as creatine kinase, pyruvate kinase, triosephosphate isomerase, and ubiqitin; housekeeping proteins, such as heat shock protein; contractile proteins, such as myosin heavy chain; actin; and also MHC isoforms and actin isoforms. The mass spectra of 20 protein spots significantly matched (protein score >83; P < 0.05) an online database. In CMP, there were unique proteins that were present only in the fast-growth population: gi|118099530 , gi|20664362 , gi|71895043 , gi|114794125 , gi|297343122 , and gi|71895043 . This information identified protein markers associated with growth rate and water holding capacity. Some of those protein markers could be added to the chicken database.


Assuntos
Galinhas/crescimento & desenvolvimento , Carne/análise , Proteínas Musculares/análise , Proteômica , Água/análise , Animais , Galinhas/metabolismo , Expressão Gênica , Proteínas Musculares/química , Proteínas Musculares/genética , Músculo Esquelético/química , Músculo Esquelético/crescimento & desenvolvimento , Mapeamento de Peptídeos , Solubilidade , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
17.
J Sci Food Agric ; 91(1): 171-7, 2011 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-20853275

RESUMO

BACKGROUND: Clarification of citrus juice is a severe quality defect related to pectin methylesterase (PME) activity. PME activity and calcium chelation of pectic acid as well as other physical interactions of cloud components influence cloud stability. The cloud stability and physical properties of pulp-free, fresh juice with and without ammonium oxalate (AO) at pH 4.0 and pH 5.5 was evaluated. RESULTS: The only juice to clarify in the 3-week study was the sample without AO at pH 4.0. Particle size analysis showed that the samples at pH 4.0 were larger than those at pH 5.5, and samples at pH 5.5 had a more negative zeta potential than samples at pH 4.0. Furthermore, cloud particle size increased and then decreased prior to the onset of clarification. CONCLUSION: Ammonium oxalate prevented sedimentation via calcium pectate cross-bridges and subsequent clarification. Interaction of cloud constituents, change in particle size with pH and change in particle size with storage time suggest that, in addition to electrostatic attraction and calcium binding, cloud particles associate and dissociate via non-covalent, non-electrostatic interactions.


Assuntos
Bebidas/normas , Cálcio/química , Citrus sinensis , Frutas , Concentração de Íons de Hidrogênio , Oxalatos/química , Tecnologia de Alimentos , Tamanho da Partícula , Pectinas/química , Solubilidade
18.
Colloids Surf B Biointerfaces ; 74(1): 178-85, 2009 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-19683899

RESUMO

W/O/W double emulsions (DEs) stabilized by charged soluble complexes of whey protein isolate (WPI) and modified pectins were investigated in relation to their stability and the release of two types of electrolytes, NaCl and sodium ascorbate. WPI alone cannot properly stabilize the DEs. The droplet size is relatively large (100 microm) and increases with time. However, addition of modified pectin to form a soluble complex with WPI significantly improved the stability. DEs prepared with two types of oils (medium chain triglycerides (MCT) and R(+)-limonene) were studied by measuring droplet size, creaming, viscosity, and electrolyte release. Irrespective of their very different oil phase nature, both emulsions were stable against coalescence, but R(+)-limonene formed smaller droplets (25 microm) than MCT (35 microm). The electrolyte release rate was significantly higher from the R(+)-limonene that formed DEs with much lower viscosity. R(+)-limonene-DE released 75% of the NaCl after 28 days, while MCT-DE released only 50%. NaCl was released more slowly than sodium ascorbate. Apparently, the release mechanism from R(+)-limonene-DE was found to be "thinning the outer interface and release of the entire inner droplets" while it seems that the release from MCT-DE was slower and "diffusion controlled". DEs stabilized by WPI/C63 released 12% of the sodium ascorbate after 1 day in milk and remained stable for at least 8 days. However, DEs stabilized with only WPI released about 50% of the sodium ascorbate after 1 day, and phase separated after 8 days.


Assuntos
Ácido Ascórbico/química , Eletrólitos/química , Proteínas do Leite/isolamento & purificação , Óleos/química , Pectinas/química , Cloreto de Sódio/química , Água/química , Animais , Condutividade Elétrica , Emulsões , Glucose/química , Concentração de Íons de Hidrogênio , Leite , Proteínas do Leite/química , Solubilidade , Temperatura Ambiente , Proteínas do Soro do Leite
19.
J Inflamm (Lond) ; 5: 1, 2008 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-18261214

RESUMO

BACKGROUND: This study tested the ability of a characterized extract of Polygonum cuspidatum (PCE) to inhibit mouse ear inflammation in response to topical application of 12-O-tetradecanoylphorbol-13-acetate (TPA). METHODS: A 50% (wt:vol) ethanolic solution of commercial 200:1 PCE was applied to both ears of female Swiss mice (n = 8) at 0.075, 0.15, 0.3, 1.25 and 2.5 mg/ear 30 min after TPA administration (2 mug/ear). For comparison, 3 other groups were treated with TPA and either 1) the vehicle (50% ethanol) alone, 2) indomethacin (0.5 mg/ear), or 3) trans-resveratrol (0.62 mg/ear). Ear thickness was measured before TPA and at 4 and 24 h post-TPA administration to assess ear edema. Ear punch biopsies were collected at 24 h and weighed as a second index of edema. Myeloperoxidase activity was measured in each ear punch biopsy to assess neutrophil infiltration. RESULTS: PCE treatment at all doses significantly reduced ear edema compared to the TPA control. The PCE response was dose-dependent and 2.5 mg PCE significantly inhibited all markers of inflammation to a greater extent than indomethacin (0.5 mg). MPO activity was inhibited at PCE doses >/= 1.25 mg/ear. Trans-resveratrol inhibited inflammation at comparable doses. CONCLUSION: PCE inhibits development of edema and neutrophil infiltration in the TPA-treated mouse ear model of topical inflammation.

20.
Carbohydr Res ; 340(17): 2620-9, 2005 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-16216228

RESUMO

Valencia pectinmethylesterase (PME) fractions, B-PME, containing 36 and 13 kDa protein bands and U-PME, containing a 36 and 27 kDa protein bands, were used to de-esterify original pectin (O-Pec) from 73% degree of esterification (%DE) to 63% (B-Pec) and 61% DE (U-Pec), respectively. Most O-Pec eluted from ion exchange chromatography at low salt concentration and a smaller component eluted at higher ionic strength. B-Pec and U-Pec eluted as one broad peak at higher ionic strength. PME modification did not change molecular weight: O-pectin (134,000 g/mol), U-Pec (133,850 g/mol), and B-Pec (132,250 g/mol). The NMR signal of GG and GGG increased after modification, whereas the signal of EE and EEE decreased. The negative zeta-potential increased with pH for all pectins. U-PME and B-PME created differently modified pectins that vary in degree and length of multiple attacks and fraction of the pectin population that was modified.


Assuntos
Hidrolases de Éster Carboxílico/metabolismo , Citrus sinensis/enzimologia , Pectinas/química , Pectinas/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Ressonância Magnética , Peso Molecular , Potenciometria , Espalhamento de Radiação
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