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1.
Food Chem ; 298: 125079, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260959

RESUMO

Citral-in-water emulsions were prepared with two different essential oil concentrations of 2.5 and 5.0% (w/w), then spray-dried in the presence of the same amount of maltodextrins (20%). The microcapsules were prepared with two different emulsifier compositions: monolayer microcapsules (ML) stabilized by sodium caseinate alone and layer-by-layer microcapsules (LBL) stabilized by sodium caseinate and pectin. The encapsulation efficiency was higher for LBL microcapsules (e.g. 99.6 ±â€¯0.4% for 2.5% citral) than that for ML ones (e.g. 78.6 ±â€¯0.6% for 2.5% citral) which confirm that the additional pectin layer was able to protect citral during the spray-drying process whatever citral concentration. Furthermore, our results showed that the antibacterial activity of the obtained microcapsules significantly depends on both citral concentration and interfacial membrane composition. The presence of two layers surrounding the citral droplets may result in a progressive and controlled release of the encapsulated citral.


Assuntos
Emulsões/química , Monoterpenos/química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Cápsulas/química , Caseínas/química , Dessecação , Listeria/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Óleos Voláteis/química , Tamanho da Partícula , Pectinas/química , Polissacarídeos/química , Staphylococcus aureus/efeitos dos fármacos
2.
Food Chem ; 300: 125194, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31325749

RESUMO

The effects of near freezing temperature (NFT) storage at -1.9 °C on cell wall degradation of 'Shushanggan' apricot was studied comparing to 0 °C and 5 °C storage. Our results indicated that NFT storage strongly inhibited the solubilization of Na2CO3-soluble pectin and cellulose, by the suppression of cell wall modifying enzymes (polygalacturonase, ß-Galactosidase, pectin methyl esterase and cellulase) and related genes expressions. The loss of side chains was the main modification in CDTA (Cyclohexane-diamine-tetraacetic Acid)-soluble pectin during storage and made the main contribution to the softening of apricot, while the loss of side chain was suppressed by NFT storage. Microscopic observation showed that NFT storage delayed the degradation of pectin fraction and protected cell wall structure from loosing. This study proves that NFT storage is an effective technology to suppress the cell wall polysaccharides degradation and ultrastructure modification of apricot.


Assuntos
Parede Celular/ultraestrutura , Armazenamento de Alimentos/métodos , Polissacarídeos/química , Prunus armeniaca/química , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/metabolismo , Parede Celular/química , Parede Celular/metabolismo , Celulose/química , Temperatura Baixa , Congelamento , Frutas/química , Frutas/citologia , Frutas/ultraestrutura , Pectinas/química , Células Vegetais/química , Células Vegetais/ultraestrutura , Poligalacturonase/química , Poligalacturonase/metabolismo , Polissacarídeos/metabolismo , Prunus armeniaca/citologia , Solubilidade , beta-Galactosidase/química , beta-Galactosidase/metabolismo
3.
Food Chem ; 300: 125171, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31330369

RESUMO

This study aimed to examine the modification effect of whey protein concentrate (WPC), WPC-gum arabic (WPC-GA) or WPC-high methoxyl pectin (WPC-PEC) complex to tailor-modify W/O/W emulsion for secondary microencapsulation of hydrophilic arbutin and hydrophobic coumaric acid. The stability and rheological properties of coated emulsions, encapsulation yield, release and degradation kinetics of arbutin and coumaric acid were investigated. Results revealed that WPC-PEC complex (at the ratio of 1:3) coating W/O/W emulsion exhibited the highest viscosity and stability, with the highest encapsulation yield of 91.08% for arbutin and 80.92% for coumaric acid, respectively. Tighter coating structure of the WPC-PEC complex (1:3) forming a stronger gel network structure was confirmed, accounting for the larger mean particle size of 569.67 nm. Moreover, the WPC-PEC (1:3) coating W/O/W emulsion also showed controlled release of arbutin and coumaric acid in simulated conditions. The k value of degradation kinetics for arbutin (7.99 × 10-4 at pH = 1.2, 4.19 × 10-4 at 90 °C and 7.52 × 10-4 at UV-C treatment) and coumaric acid (5.18 × 10-4 at pH = 1.2, 3.24 × 10-4 at 90 °C and 6.90 × 10-4 at UV-C treatment) indicated low degradation rate. The present study revealed that the WPC-PEC (1:3) coating W/O/W emulsion could provide a better synergistic effect on higher encapsulation yield and stability of arbutin and coumaric acid.


Assuntos
Arbutina/química , Cápsulas/química , Ácidos Cumáricos/química , Emulsões/química , Polissacarídeos/química , Arbutina/farmacocinética , Composição de Medicamentos , Goma Arábica/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula , Pectinas/química , Reologia , Temperatura Ambiente , Raios Ultravioleta , Viscosidade , Proteínas do Soro do Leite/química
4.
J Agric Food Chem ; 67(29): 8197-8204, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31287317

RESUMO

Potato pectin contains some proteinaceous components and exhibits emulsifying and emulsion stabilizing abilities. The objective of this study was to elucidate the effect of the pectin moiety of the pectin-protein conjugate present in pectic extracts from potato tubers on their interfacial properties. Potato pectin was extracted from highly purified cell wall materials to avoid the contamination of unconjugated proteins. The abilities of the potato pectin to adsorb to graphite surfaces and to resist surfactant-induced competitive displacement from the air-water interface were investigated using atomic force microscopy. The pectin moiety of the potato pectin was capable of adsorbing to graphite surfaces even after alkali treatment. Furthermore, the potato pectin exhibited enhanced resistance to surfactant-induced competitive displacement from the interface as a result of the formation of network structures of self-assembled pectin moieties at the interface. The present results suggest the importance of the pectin moiety with regard to the interfacial properties of potato pectin.


Assuntos
Pectinas/química , Extratos Vegetais/química , Proteínas de Plantas/química , Solanum tuberosum/química , Tensoativos/química , Ar/análise , Tubérculos/química , Água/química
5.
J Agric Food Chem ; 67(33): 9344-9353, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31361957

RESUMO

Anthocyanins determine the color and potential health-promoting properties of red fruit juices, but the juices contain remarkably less anthocyanins than the fruits, which is partly caused by the interactions of anthocyanins with the residues of cell wall polysaccharides like pectin. In this study, pectin was modified by ultrasound and enzyme treatments to residues of polysaccharides and oligosaccharides widely differing in their molecular weight. Modifications decreased viscosity and degrees of acetylation and methylation and released smooth and hairy region fragments. Native and modified pectin induced different effects on the concentrations of individual anthocyanins after short-term and long-term incubation caused by both hydrophobic and hydrophilic interactions. Results indicate that both pectin and anthocyanin structure influence these interactions. Linear polymers generated by ultrasound formed insoluble anthocyanin complexes, whereas oligosaccharides produced by enzymes formed soluble complexes with protective properties. The structure of the anthocyanin aglycone apparently influenced interactions more than the sugar moiety.


Assuntos
Antocianinas/química , Beta vulgaris/química , Pectinas/química , Acetilação , Cor , Frutas/química , Sucos de Frutas e Vegetais/análise , Interações Hidrofóbicas e Hidrofílicas , Metilação , Peso Molecular , Ultrassom , Viscosidade
6.
Carbohydr Polym ; 220: 12-21, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31196530

RESUMO

The assessment of several ink formulations for 3D printing based on two natural macromolecular compounds is presented. In the current research we have exploited the fast crosslinking potential of pectin and the remarkable shear-thinning properties of carboxylated cellulose nanofibrils, which is known to induce a desired viscoelastic behavior. Prior to 3D printing, the viscoelastic properties of the polysaccharide inks were evaluated by rheological measurements and injectability tests. The reliance of the printing parameters on the ink composition was established through one-dimensional lines printing, the base units of 3D-structures. The performance of the 3D-printed structures after ionic cross-linking was evaluated in terms of mechanical properties and rehydration behavior. MicroCT was also used to evaluate the morphology of the 3D-printed objects regarding the effect of pectin/nanocellulose ratio on the geometrical features of scaffolds. The proportionality between the two polymers proved to be the determining factor for the firmness and strength of the printed objects.


Assuntos
Celulose/análogos & derivados , Tinta , Nanofibras/química , Pectinas/química , Impressão Tridimensional , Materiais Biocompatíveis/química , Hidrogéis/química , Reologia , Engenharia Tecidual , Tecidos Suporte/química
7.
J Sci Food Agric ; 99(14): 6191-6198, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31250441

RESUMO

BACKGROUND: Pectin characteristics from different parts of lemon fruit (Citrus limon L.) were studied as a basis for assessing their suitability for functional applications. Pectin was extracted from lemon albedo, lemon core parts and membranes, and lemon extract using an aqueous extraction protocol. The composition and structural properties of the isolated pectins were examined by means of complementary analytical methods to assess their molecular characteristics for potential industrial applications. RESULTS: The isolation protocol yielded pectins that were predominantly composed of galacturonic acid, with differences in the degree of methylation and neutral sugars content, and with low protein content, indicating high-purity materials. The same extraction protocol resulted in differences in yield and purity between the three different parts of lemon fruit, and in structural variations in the pectin backbone, as evidenced by differences in sugar composition and molecular weight. Solutions of the isolated lemon pectins exhibited pseudoplastic behavior. Macromolecular characterization showed that the lemon extract pectin had the highest molecular weight and hydrodynamic volume, followed by lemon core and lemon albedo pectin. CONCLUSION: The work demonstrates that pectins with distinct structural properties may be extracted from different parts of lemon wastes and used for different technological purposes. © 2019 Society of Chemical Industry.


Assuntos
Citrus/química , Sucos de Frutas e Vegetais/análise , Pectinas/química , Extratos Vegetais/química , Resíduos/análise , Frutas/química , Ácidos Hexurônicos/análise , Peso Molecular , Pectinas/isolamento & purificação , Extratos Vegetais/isolamento & purificação
8.
Analyst ; 144(13): 4111-4120, 2019 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-31172988

RESUMO

The endo-polygalacturonase enzyme (endoPG: EC 3.2.1.15) plays an important role in the fruit juice and wine industries, so the development of new tools for the quantitative and qualitative analysis of its enzymatic action is necessary. In this work, we report the development of a simple, fast and practical method that did not use any chemical reagent to identify and evaluate the action of the endoPG enzyme, produced by the yeast Kluyveromyces marxianus CCT3172, using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy combined with principal component analysis-linear discriminant analysis (PCA-LDA). This method evaluated the action of the endoPG enzyme on the polygalacturonic acid (PGA) substrate at 5 different times (0, 10, 15, 20 and 30 minutes), and at each time interval the samples were analyzed by ATR-FTIR. It was demonstrated that there was clear segregation between the samples that were and that were not subjected to the action of the endoPG enzyme, and it was also possible to distinguish the samples that were subjected to different incubation times with the enzyme. Through PCA-LDA it was possible to obtain wavelengths that are biomarkers for this enzymatic reaction and the observed changes as a function of hydrolysis duration were found to be in agreement with the breakdown of the glycosidic chain (1011 cm-1-CH-O- CH stretching) of PGA and release of oligosaccharides (1078 cm-1 C-OH elongation). The activity of the endoPG enzyme and the release of galacturonic acid were verified by the dinitrosalicylic acid (DNS) method in all samples. The efficacy of an automatic classifier using a principal component analysis-linear discriminant classifier (PCA-LDC) was evaluated to diagnose the action of the endoPG enzyme. The results showed an accuracy of 100% for the identification of the endoPG enzyme action and from 91.67% to 100% for classification according to the hydrolysis duration in which PGA was exposed to endoPG. The present study indicates that this methodology may be a new approach for the qualitative evaluation of the endoPG enzyme with the potential to be used in laboratories and industries.


Assuntos
Kluyveromyces/enzimologia , Pectinas/química , Poligalacturonase/química , Catálise , Colorimetria , Análise Discriminante , Hidrólise , Cinética , Análise de Componente Principal , Espectroscopia de Infravermelho com Transformada de Fourier
9.
Food Chem ; 296: 47-55, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31202305

RESUMO

The redfleshed pulp discarded from pink guava puree industry is a rich source of lycopene and pectin. In this study, we developed a facile extraction process employing water as the primary extraction medium to isolate the lycopene and pectin from pink guava decanter. When the decanter was suspended in water, the complexation of lycopene and pectin formed the cloudy solution, where the colloidal complexes were recovered through centrifugation. The presence of lycopene and pectin in the complex was confirmed by the spectroscopic, microscopic and chromatographic analyses. The lycopene fractionated from the complexes had a purity level of 99% and was in all-trans configuration. The colloidal complexes yielding the highest concentration of lycopene was obtained at pH 7, 1% (w/v) solid loading and 25 °C. The experimental data of time-course extraction of lycopene-pectin complex were best fitted with two-site kinetic model, hinting the fast- and slow-release phases in the extraction process.


Assuntos
Licopeno/química , Pectinas/química , Psidium/química , Cromatografia Líquida de Alta Pressão , Cor , Concentração de Íons de Hidrogênio , Isomerismo , Cinética , Licopeno/análise , Licopeno/isolamento & purificação , Pectinas/análise , Pectinas/isolamento & purificação , Psidium/metabolismo , Espectrofotometria , Temperatura Ambiente , Água/química
10.
Food Chem ; 297: 124943, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253332

RESUMO

The aim of this study was to dissociate the effect of atomization from that of heating during the spray-drying of Low Methoxyl (LM) pectin/sodium caseinate complexes. The properties of these complexes were studied by measuring turbidity, particle size distribution, zeta-potential, as well as surface hydrophobicity of caseinate within the formed complexes. The results showed that the spraying step had a significant effect on the charge and the size of the complexes. In fact, the application of atomization resulted in the dissociation of caseinate/pectin aggregates especially for high pectin concentrations. Besides, the analysis of the surface hydrophobicity of caseinate indicated that complexation with high concentrations of pectin is able to protect the structure of the protein against heat denaturation. This study allowed a better understanding of the influence of atomization and heat treatment (during the dehydration step) on the molecular interactions within caseinate/pectin complexes.


Assuntos
Caseínas/química , Dessecação/métodos , Pectinas/química , Temperatura Alta , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula
11.
Water Sci Technol ; 79(8): 1484-1493, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31169506

RESUMO

A novel adsorbent, composed of cross-linked de-esterified pectin microspheres, was prepared via cross-linking with Ca(II) and modification by de-esterified pectin, low-methoxyl pectin (LMP) and pectic acid (PA). Fourier transform infrared (FTIR), energy dispersive spectrometry (EDS), scanning electron microscopy (SEM) and atomic absorption spectroscopy (AAS) were applied too, exhibiting a successful fabrication, good adsorption ability, and well-defined surface microstructure beneficial to Pb(II) adsorption. The adsorption ability of pectin microspheres (PMs), low-methoxyl pectin microspheres (LMPMs) and pectic acid microspheres (PAMs) for Pb(II) in aqueous solution were explored. The maximum adsorption capacity of PMs, LMPMs and PAMs was 127 mg·g-1, 292 mg·g-1 and 325 mg·g-1 at pH 5.0 respectively, indicating a great improvement of LMPMs and PAMs in the adsorption ability for Pb(II) compared with PMs. Furthermore, the adsorption mechanism was proposed. The experimental data were well fitted with pseudo-second-order kinetic and Langmuir isotherm models. Five-cycle reusability tests demonstrated that microspheres could be used repeatedly. All the results confirmed that LMPMs and PAMs, which presented outstanding adsorption capability and reusability, could be a good candidate for wastewater purification.


Assuntos
Cálcio/química , Chumbo/química , Microesferas , Pectinas/química , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier , Águas Residuárias
12.
J Agric Food Chem ; 67(26): 7435-7447, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31244205

RESUMO

Pectic oligosaccharides (POS) from citrus and apple pectin hydrolysis using ViscozymeL and Glucanex200G have been obtained. According to the results, maximum POS formation was achieved from citrus pectin after 30 min of hydrolysis with ViscozymeL, with a yield of 652 mg g-1 and average molecular mass ( Mw) of 0.8-2.5 kDa, while with Glucanex200G, the yield was 518 mg g-1 and Mw was 0.8-7.1 kDa. Digalacturonic and trigalacturonic acids were identified among other low Mw compounds as di- and tri-POS. In addition, differences in GC-MS spectra of all oligosaccharides found in the hydrolysates were studied by employing random forests and other algorithms to identify structural differences between the obtained POS, and high prediction rates were shown for new samples. Chemical structures were proposed for some influential m/ z ions, and 12 association rules that explain differences according to pectin and enzyme origin were built. This information could be used to establish structure-function relationships of POS.


Assuntos
Citrus/química , Malus/química , Complexos Multienzimáticos/química , Oligossacarídeos/química , Pectinas/química , Extratos Vegetais/química , Biocatálise , Cromatografia Gasosa-Espectrometria de Massas , Hidrólise , Peso Molecular
13.
BMC Plant Biol ; 19(1): 271, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31226937

RESUMO

BACKGROUND: The heavy metal cadmium (Cd) accumulates in the environment due to anthropogenic influences. It is unessential and harmful to all life forms. The plant cell wall forms a physical barrier against environmental stress and changes in the cell wall structure have been observed upon Cd exposure. In the current study, changes in the cell wall composition and structure of Medicago sativa stems were investigated after long-term exposure to Cd. Liquid chromatography coupled to mass spectrometry (LC-MS) for quantitative protein analysis was complemented with targeted gene expression analysis and combined with analyses of the cell wall composition. RESULTS: Several proteins determining for the cell wall structure changed in abundance. Structural changes mainly appeared in the composition of pectic polysaccharides and data indicate an increased presence of xylogalacturonan in response to Cd. Although a higher abundance and enzymatic activity of pectin methylesterase was detected, the total pectin methylation was not affected. CONCLUSIONS: An increased abundance of xylogalacturonan might hinder Cd binding in the cell wall due to the methylation of its galacturonic acid backbone. Probably, the exclusion of Cd from the cell wall and apoplast limits the entry of the heavy metal into the symplast and is an important factor during tolerance acquisition.


Assuntos
Cádmio/toxicidade , Parede Celular/química , Medicago sativa/efeitos dos fármacos , Pectinas/química , Poluentes do Solo/toxicidade , Cromatografia Líquida , Perfilação da Expressão Gênica , Ácidos Hexurônicos/metabolismo , Espectrometria de Massas , Monossacarídeos/análise , Proteínas de Plantas/metabolismo , Caules de Planta/química , Polissacarídeos/química , Proteoma
14.
J Food Sci ; 84(7): 1776-1783, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31218715

RESUMO

Citrus pectin hydrolysates (Citrus paradisi [Mafc.]) from "Foster," "Red Shambar," "Tangelo Orlando," and "Citrumelo Swingle" cultivars were obtained by partial chemical hydrolysis and their properties as culture media (sole carbon/nutrient source) and encapsulating agents of Lactobacillus plantarum CIDCA 83114 were evaluated. The concentration of neutral sugars was maximal after 2-hour hydrolysis. All hydrolysates were rich in glucose >xylose >galactose >galacturonic acid >mannose >arabinose. "Citrumelo Swingle" cultivar was the one with the highest concentration of xylose. After 24 hr of fermentation with L. plantarum CIDCA 83114, bacterial viability increased from 6.76 ± 0.14 to almost 9 log CFU/mL, and lactic acid concentration, from 2.63 ± 0.41 to 7.82 ± 0.15 mmol/L in all hydrolysates. Afterwards, bacteria were entrapped in pectate-calcium beads by ionotropic gelation. Bacterial viability did not significantly decrease after freeze-drying and storage the beads at 4 °C for 45 days. PRACTICAL APPLICATION: Pectin hydrolysates were adequate culture media for microorganisms, as determined by the viabililty and lactic acid production. Considering that citrus peels are agro-wastes obtained in large quantities, their use as encapsulating materials provides a solution to overcome the environmental problem they entail.


Assuntos
Citrus paradisi/química , Meios de Cultura/metabolismo , Lactobacillus plantarum/química , Pectinas/química , Citrus paradisi/metabolismo , Meios de Cultura/química , Fermentação , Liofilização , Hidrólise , Ácido Láctico/análise , Ácido Láctico/metabolismo , Lactobacillus plantarum/classificação , Lactobacillus plantarum/crescimento & desenvolvimento , Lactobacillus plantarum/metabolismo , Pectinas/metabolismo , Açúcares/análise , Açúcares/metabolismo
15.
Carbohydr Polym ; 219: 181-190, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31151515

RESUMO

Water-soluble fraction (WSF), CDTA-soluble fraction (CSF), sodium carbonate-soluble fraction (SSF), loosely-bonding KOH-soluble fractions (LKF) and tightly-bonding KOH-soluble fractions (TKF) were sequentially extracted from tomato cell wall polysaccharides. Physicochemical properties and functional bioactivities of these different bonding state tomato fruit polysaccharides (DBTP) were investigated. WSF, CSF and SSF were identified as pectic polysaccharides, while LKF and TKF were identified as hemicellulose. WSF, possessing plenty of galacturonic acids, was considered as an aggregative of linear homogalacturonan with extremely high molecular weight. CSF and SSF, rich in neutral sugars side chains, contained abundant rhamnogalacturonan regions. These polysaccharides exhibited distinct surface morphology and special FTIR spectrums. Thermal analysis manifested that LKF and TKF exhibited higher thermal stability. WSF and SSF showed higher apparent viscosity and elasticity. Assays for functional bioactivities suggested that CSF and SSF displayed stronger antioxidant activities, while CSF, SSF and TKF exhibited higher hypolipidemic activities.


Assuntos
Parede Celular/química , Frutas , Lycopersicon esculentum , Polissacarídeos , Antioxidantes/farmacologia , Elasticidade , Frutas/citologia , Frutas/metabolismo , Hipolipemiantes/farmacologia , Lycopersicon esculentum/citologia , Lycopersicon esculentum/metabolismo , Pectinas/química , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Polissacarídeos/farmacologia , Solubilidade , Viscosidade
16.
Carbohydr Polym ; 219: 29-38, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31151527

RESUMO

Multi-objective sequential fractionation of mango (Mangifera indica L.) peels for pectin and anthocyanins in a biorefinery, was investigated with the aims of enhancing pectin purity, bioactivity and increasing recovered products. Anthocyanins were extracted from mango peels based on a Box-Behnken experimental design (ethanol concentration (50-80%), acetic acid concentration (0.1-2%), time (60-150 min) and temperature (25 °C)). The remaining residue was subsequently fractionated to recover pectin. The optimum anthocyanin conditions (67.45% ethanol, 0.24% acetic acid and 60 min) resulted in pectin with a 5.5% higher antioxidant activity, it was 23% richer in polygalacturonic acid (PGA) and had a yield of 31% w/w higher than conventionally extracted pectin. An anthocyanin extract with anthocyanin contents, polyphenol contents, and antioxidant activity of 22.33 mg/100 g, 132.62 mg/g, and 1.36 µg gallic acid equivalent, respectively, was obtained. Therefore, the sequential extraction of anthocyanins and pectin improves pectin functional properties and increases the mango peel value potential.


Assuntos
Antocianinas , Fracionamento Químico/métodos , Frutas/química , Mangifera/química , Pectinas , Antocianinas/química , Antocianinas/isolamento & purificação , Pectinas/química , Pectinas/isolamento & purificação , Projetos de Pesquisa
17.
Food Chem ; 293: 429-437, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151631

RESUMO

To achieve a low methoxy-pectin nanocomposite film with maximum resistance to water and acceptable mechanical properties, the interactions of different glycerol concentrations and Ca2+ ions in both steps of crosslinking on the swelling degree (SD) and mechanical properties of prepared films were investigated using response surface methodology (RSM). Accordingly, quadratic second-order models were fitted to the SD and tensile strength responses; while the cubic model demonstrated a good relation between independent variables and elongation at break respectively. As a compromise between water resistance and mechanical properties of the prepared films, the use of 0.5% Ca2+, 0.75% Gly1 and 7.5% Gly2 is suggested as the optimum condition. Generally, crosslinking of pectin polymer with Ca2+ cations in the second step along with incorporation of nanocellulose into pectin film led to the formation of more flexible and completely water insoluble pectin nanocomposite film in comparison to the other polymers crosslinked with Ca2+ cations.


Assuntos
Cálcio/química , Glicerol/química , Nanocompostos/química , Pectinas/química , Água/química , Cátions/química , Celulose/química , Polímeros , Resistência à Tração
18.
Food Chem ; 293: 358-367, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151623

RESUMO

To better understanding the role of cell wall pectic polysaccharides (CWPs) on the formation of textural properties of carrot chips dried by instant controlled pressure drop technology (French for Détente Instantanée Contrôlée, DIC), the characteristics of CWPs from ground tissue (GT), junction of ground and vascular tissue (JT), and vascular tissue (VT) of carrot were investigated. Larger expansion volume was obtained in the carrot chips derived from GT, which accompanied with superior textural qualities compared with the chips derived from JT and VT. Remarkable differences were obtained in the amount of pectic fractions, galacturonic acid content, degree of methoxylation, sugar composition and linearity of CWPs that fractionated from different tissue zones of raw carrots. The characteristics of CWPs was confirmed to be a substantial factor that significantly affected the expansion ratio and textural properties of the DIC-dried carrot chips, which providing a mechanistic insight of the relationship between variation in CWPs and the expanding behaviors of DIC-dried fruits and vegetables.


Assuntos
Daucus carota/química , Polissacarídeos/química , Parede Celular/química , Manipulação de Alimentos/métodos , Ácidos Hexurônicos/análise , Pectinas/química , Polissacarídeos/análise , Pressão , Açúcares/análise
19.
J Agric Food Chem ; 67(27): 7755-7764, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31251611

RESUMO

Pectic polysaccharides from New Zealand (NZ) spinach (Tetragonia tetragonioides) and karaka berries (Corynocarpus laevigatus) were extracted and analyzed. NZ spinach polysaccharides comprised mostly homogalacturonan (64.4%) and rhamnogalacturonan I (5.8%), with side chains of arabinan (8.1%), galactan (2.2%), and type II arabinogalactan (7.1%); karaka berry polysaccharides comprised homogalacturonan (21.8%) and rhamnogalacturonan I (10.0%), with greater proportions of side chains (arabinan, 15.6%; galactan, 23.8%; and type II arabinogalactan, 19.3%). Screening of gut commensal Bacteroides showed that six were able to grow on the NZ spinach extract, while five were able to grow on the karaka berry extract. Analysis of the polysaccharides remaining after fermentation, by size-exclusion chromatography and constituent sugar analysis, showed that the Bacteroides species that grew on these two substrates showed preferences for the different pectic polysaccharide types. Our data suggest that, to completely degrade and utilize the complex pectin structures found in plants, members of Bacteroides and other bowel bacteria work as metabolic consortia.


Assuntos
Aizoaceae/química , Bacteroides/crescimento & desenvolvimento , Magnoliopsida/química , Pectinas/metabolismo , Polissacarídeos/metabolismo , Bacteroides/metabolismo , Fermentação , Frutas/química , Microbioma Gastrointestinal/fisiologia , Nova Zelândia , Pectinas/análise , Pectinas/química , Folhas de Planta/química , Polissacarídeos/química , Polissacarídeos/isolamento & purificação
20.
Food Chem ; 297: 125021, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253338

RESUMO

In this study, the effects of ultrasonic intensity on conformational changes in aqueous citrus pectin solution under ultrasonic processing and its possible transition mechanism were investigated. The results demonstrated that higher ultrasonic intensity (104.7 W/cm2) caused larger alterations in the molecular and conformational parameters of the semiflexible pectin (Mark-Houwink relation exponent a: 0.820, conformational parameter α: 0.607, structural parameter ρ: 2.22) in aqueous solution. Meanwhile, the semiflexible chain of pectin became more flexible (a: 0.804, α: 0.601, ρ: 1.75) at higher ultrasonic intensity in aqueous solution, as was verified by atomic force microscopy. Moreover, conformational changes in pectin from semiflexible chains to flexible chains or even flexible coils (a: 0.791, α: 0.597, ρ: 1.70) could be attributed to the decreased degree of methoxylation and neutral sugars in side chains and the destruction of inter- and intramolecular hydrogen bonds under ultrasonic processing. Therefore, these results have important implications for understanding the ultrasonic modification of pectin.


Assuntos
Citrus/metabolismo , Pectinas/química , Configuração de Carboidratos , Cromatografia Líquida de Alta Pressão , Dicroísmo Circular , Ligações de Hidrogênio , Microscopia de Força Atômica , Sonicação , Açúcares/química , Viscosidade
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