RESUMO
In this study, a beverage made from a combination of Agave sap (AS) and prickly pear juice (PPJ) was analyzed for its nutrients and bioactive and potentially health-promoting compounds. The beverage was evaluated for its ability to act as an antioxidant, regulate glycemic properties, and undergo gut bacterial fermentation in vitro. The major mono- and oligosaccharides present in the beverage were galacturonic acid (217.74 ± 13.46 mg/100 mL), rhamnose (227.00 ± 1.58 mg/100 mL), and fructose (158.16 ± 8.86 mg/mL). The main phenolic compounds identified were protocatechuic acid (440.31 ± 3.06 mg/100 mL) and catechin (359.72 ± 7.56 mg/100 mL). It was observed that the beverage had a low glycemic index (<40) and could inhibit digestive carbohydrases. The combination of ingredients also helped to reduce gas production during AS fermentation from 56.77 cm3 to 15.67 cm3. The major SCFAs produced during fermentation were butyrate, acetate, and propionate, with valerate being produced only during the late fermentation of the AS. This beverage is rich in bioactive compounds, such as polyphenols and dietary fiber, which will bring health benefits when consumed.
Assuntos
Agave , Antioxidantes , Sucos de Frutas e Vegetais , Agave/química , Sucos de Frutas e Vegetais/análise , Antioxidantes/química , Antioxidantes/farmacologia , Antioxidantes/análise , Fermentação , Hidroxibenzoatos/análise , Polifenóis/análise , Polifenóis/química , Pyrus/química , Fenóis/análise , Fenóis/química , Ramnose/análise , Ramnose/química , Catequina/análise , Catequina/química , Catequina/análogos & derivados , Ácidos HexurônicosRESUMO
A structural characterization of polysaccharides from edible tropical fruit named starfruit (Averrhoa carambola L.) was carried out. After the purification steps, two homogeneous fractions were obtained. Fraction 50R was composed of rhamnose, arabinose, galactose and uronic acid in 4.3:56.2:37.4:2M ratio, respectively and fraction 10R was composed of rhamnose, arabinose, galactose and uronic acid in 2.8:65.8:28.5:3M ratio, respectively. Methylation and NMR spectroscopy analyses showed that these fractions are formed by pectic arabinogalactans, which contain (1â3), (1â6) and (1â3,6)-linked Galp units. The side chains have 3-O-, 5-O- and 3,5-di-O-linked α-Araf and nonreducing end-units of α-Araf, Arap, ß-Galp and α-GlcpA. These arabinogalactans were linked to type I rhamnogalacturonans.
Assuntos
Averrhoa/química , Frutas/química , Galactanos/química , Pectinas/química , Polissacarídeos/química , Arabinose/análise , Galactose/análise , Ramnose/análise , Ácidos Urônicos/análiseRESUMO
Several reports have focused on utilization of post-harvest residues of crops, while neglecting those residues produced by mango processing. These residues represent a waste of nutrients and a source of environmental contaminants. Such by-products could be valuable sources of dietary fiber (DF), antioxidant compounds, and single carbohydrates. The aim of this study was to evaluate some functional properties (FP), and the content of DF and polyphenols (PP) of the peel and coarse material obtained from residues during the industrial processing of Ataulfo and Tommy Atkins mangoes. The total dietary fiber (TDF) content was about 225 mg/g and 387 mg/g (dry weight) for the coarse material and the peel, respectively, from which soluble dietary fiber represented 23 and 42%, respectively. The main neutral sugar identified was rhamnose, especially in peels; the klason lignin (KL) content was 92 mg/g, which highlights the Ataulfo peel (Ataulfo-P) and the Tommy Atkins peel (Tommy Atkins-P). The extractable PP content in Ataulfo-P was higher than in Tommy-Atkins-P, and interesting data for non-extractable PP were obtained in the residues. FP as swelling, water holding, oil holding, and glucose absorption in the residues was studied, obtaining better functional properties when compared to cellulose fiber. The results show that mango industrial by-products, mainly from the Ataulfo-P variety, could be used as ingredients in food products because of their functional properties as well as their DF and PP content.
Assuntos
Fibras na Dieta/análise , Manipulação de Alimentos , Frutas/química , Alimento Funcional , Mangifera , Antioxidantes/análise , Resíduos Industriais , Lignina/análise , Polifenóis/análise , Ramnose/análiseRESUMO
The cell wall polysaccharides of Regina and Sunburst cherry varieties at two developmental stages were extracted sequentially, and their changes in monosaccharide composition and functional properties were studied. The loosely-attached pectins presented a lower d-galacturonic acid/rhamnose ratio than ionically-bound pectins, as well as lower thickening effects of their respective 2% aqueous solution: the lowest Newtonian viscosity and shear rate dependence during the pseudoplastic phase. The main constituents of the cell wall matrix were covalently bound pectins (probably through diferulate cross-linkings), with long arabinan side chains at the RG-I cores. This pectin domain was also anchored into the XG-cellulose elastic network. Ripening occurred with a decrease in the proportion of HGs, water extractable GGM and xylogalacturonan, and with a concomitant increase in neutral sugars. Ripening was also associated with higher viscosities and thickening effects, and to larger distribution of molecular weights. The highest firmness and compactness of Regina cherry may be associated with its higher proportion of calcium-bound HGs localized in the middle lamellae of cell walls, as well as to some higher molar proportion of NS (Rha and Ara) in covalently bound pectins. These pectins showed significantly better hydration properties than hemicellulose and cellulose network. Chemical composition and functional properties of cell wall polymers were dependent on cherry variety and ripening stage, and helped explain the contrasting firmness of Regina and Sunburst varieties.
Assuntos
Carboidratos , Pectinas , Polissacarídeos , Prunus , Carboidratos/análise , Carboidratos/química , Parede Celular/química , Celulose/química , Frutas/química , Ácidos Hexurônicos/análise , Ácidos Hexurônicos/química , Pectinas/análise , Pectinas/química , Polímeros/química , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Prunus/química , Prunus/crescimento & desenvolvimento , Ramnose/análise , Ramnose/química , ViscosidadeRESUMO
BACKGROUND: Cooking time decreases when beans are soaked first. However, the molecular basis of this decrease remains unclear. To determine the mechanisms involved, changes in both pectic polysaccharides and cell wall enzymes were monitored during soaking. Two cultivars and one breeding line were studied. RESULTS: Soaking increased the activity of the cell wall enzymes rhamnogalacturonase, galactanase and polygalacturonase. Their activity in the cell wall was detected as changes in chemical composition of pectic polysaccharides. Rhamnose content decreased but galactose and uronic acid contents increased in the polysaccharides of soaked beans. A decrease in the average molecular weight of the pectin fraction was induced during soaking. The decrease in rhamnose and the polygalacturonase activity were associated (r = 0.933, P = 0.01, and r = 0.725, P = 0.01, respectively) with shorter cooking time after soaking. CONCLUSION: Pectic cell wall enzymes are responsible for the changes in rhamnogalacturonan I and polygalacturonan induced during soaking and constitute the biochemical factors that give bean cell walls new polysaccharide arrangements. Rhamnogalacturonan I is dispersed throughout the entire cell wall and interacts with cellulose and hemicellulose fibres, resulting in a higher rate of pectic polysaccharide thermosolubility and, therefore, a shorter cooking time.
Assuntos
Culinária/métodos , Pectinas/metabolismo , Phaseolus/química , Sementes/química , Água/química , Parede Celular/enzimologia , Cotilédone/química , Cotilédone/enzimologia , Galactanos/análise , Galactanos/química , Galactose/análise , Glicosídeo Hidrolases/metabolismo , Peso Molecular , Pectinas/análise , Pectinas/química , Phaseolus/enzimologia , Proteínas de Plantas/metabolismo , Poligalacturonase/metabolismo , Ramnose/análise , Sementes/enzimologia , Solubilidade , Fatores de Tempo , Ácidos Urônicos/análise , beta-Galactosidase/metabolismoRESUMO
Structural features of the acidic, highly substituted glycanoxylan (LCP; 87% yield) from the gum exudate of the palm, Livistona chinensis, family Arecaceae, were determined. It had [alpha]D -30 degrees, Mw 1.9x10(5) and a polydispersity ratio Mw/Mn of approximately 1.0. Acid hydrolysis gave rise to Rha, Fuc, Ara, Xyl, and Gal, in a 1:6:46:44:3 molar ratio, and 12% of uronic acid was present. LCP had a highly branched structure with side-chains containing nonreducing end-units (% values are approximate) of Araf (15%), Fucp (4%), Xylp (7%), GlcpA, and 4-Me-GlcpA, and internal 2-O- (5%) and 3-O-substituted Araf (8%), and 2-O-substituted Xylp (14%) units. The (1-->4)-linked beta-Xylp main-chain units of LCP were substituted at O-3 (4%), O-2 (17%), and O-2,3 (16%). Partial acid hydrolysis gave 4-Me-alpha-GlcpA-(1-->2)-[beta-Xylp-(1-->4)](0-2)-Xyl, identified by showing that the uronic acids were single-unit side-chain substituents on O-2. Milder hydrolysis conditions removed from O-3 other side-chains containing Fucp and Araf nonreducing end-units and internal Arap, and 2-O- and 3-O-substituted Araf units. Carboxyl-reduced LCP contained 4-O-methylglucose and glucose in a 3.2:1 molar ratio, arising from GlcpA and 4-OMe-GlcpA nonreducing end-units, respectively. The gum contained small amounts of free alpha-Fucp-(1-->2)-Ara, which corresponds to structures in the polysaccharide. Free myo- and D- or L-chiro-inositol were present in a 9:1 ratio.
Assuntos
Arecaceae/química , Oligossacarídeos de Cadeias Ramificadas/química , Polissacarídeos/química , Xilanos/química , Arabinose/análise , Sequência de Carboidratos , Classificação , Fucose/análise , Galactose/análise , Cromatografia Gasosa-Espectrometria de Massas , Glucose/análise , Glucuronatos/análise , Ácido Glucurônico/análise , Hidrólise , Inositol/análise , Espectroscopia de Ressonância Magnética , Metilação , Dados de Sequência Molecular , Peso Molecular , Polissacarídeos/isolamento & purificação , Ramnose/análise , Espalhamento de Radiação , Espectrometria de Massas por Ionização por Electrospray , Ácidos Urônicos/análise , Xilanos/análise , Xilanos/classificação , Xilanos/isolamento & purificação , Xilose/análiseRESUMO
The tree Spondias dulcis, located in Venezuela, exudes a light-brown gum. The polysaccharide, isolated from the original gum, contains galactose, arabinose, mannose, rhamnose, glucuronic acid, and its 4-O-methyl derivative. Application of chemical methods, in combination with 1D and 2D NMR spectroscopy afforded interesting structural features of the gum polysaccharide. The unequivocal presence of rhamnose in the polymer structure was confirmed by chemical and spectral data [1H (1.03 ppm); 13C (16.92 ppm)]. Also confirmed was the existence of 3-O- and 6-O-substitutes galactose residues by the spectral data correlations observed in Heteronuclear Multiple Quantum Coherence (HMQC) and Heteronuclear Multiple Bond Correlation (HMBC). Also observed were unequivocal resonances for beta-D-glucuronic acid and its 4-O-methyl derivative, and the presence of 3-O-alpha-L-arabinofuranose and 3-O-beta-L-arabinopyranose residues.
Assuntos
Anacardiaceae/química , Galactanos/análise , Polissacarídeos/análise , Arabinose/análise , Configuração de Carboidratos , Sequência de Carboidratos , Cromatografia Líquida de Alta Pressão , Galactanos/química , Galactose/análise , Espectroscopia de Ressonância Magnética , Manose/análise , Dados de Sequência Molecular , Estrutura Molecular , Estruturas Vegetais/química , Polissacarídeos/química , Ramnose/análise , Xilose/análiseRESUMO
A structural study of the gum exudate from Enterolobium cyclocarpum has been carried out using chemical methods and 13C NMR spectroscopy. The results reveal that the structure of this gum is essentially a beta-(1-->3)-galactan. Some galactoses are 6-O-linked and others also occur as terminal residues. There is evidence that supports the presence of alpha-L-arabinofuranose and beta-L-arabinopyranose. beta-D-Glucuronic acid may be present as terminal and internal residues, while the 4-O-methyl-alpha-D-glucuronic acid residues exist predominantly in internal positions.
Assuntos
Polissacarídeos/análise , Árvores/química , Arabinose/análise , Configuração de Carboidratos , Isótopos de Carbono , Galactanos/análise , Galactanos/metabolismo , Galactose/análise , Glucuronatos/análise , Ácido Glucurônico , Espectroscopia de Ressonância Magnética , Polissacarídeos/química , Ramnose/análiseRESUMO
Blastocrithidia culicis is a trypanosomatid protozoon that transfers Man6GlcNAc2 in protein N-glycosylation. Compounds containing mannosyl, xylosyl, and rhamnosyl residues were found among the endo-beta-N-acetylglucosaminidase H-sensitive oligosaccharides of whole cell glycoproteins of this parasite. The compositions of some of them were as follows: Man5GlcNAc2, Man6GlcNAc2, Rha1Man5GlcNAc2, Rha2Man6GlcNAc2, Xyl1Rha2Man6-GlcNAc2, Xyl1Rha3Man6GlcNAc2, and Xyl2Rha3Man6-GlcNAc2. On the other hand, oligosaccharides containing mannosyl, xylosyl, rhamnosyl, and ribosyl units were liberated from endo-beta-N-acetylglucosaminidase-resistant glycopeptides upon treatment with N-glycanase. This is the first report on the presence of ribosyl units in eukaryote glycoconjugates, of rhamnosyl residues in asparagine-linked oligosaccharides, and of xylosyl units in high mannose-type compounds.
Assuntos
Asparagina/química , Oligossacarídeos/química , Ramnose/análise , Ribose/análise , Trypanosomatina/metabolismo , Xilose/análise , Animais , Sequência de Carboidratos , Glicoproteínas/química , Hexosaminidases , Hidrólise , Manosidases , Dados de Sequência Molecular , alfa-ManosidaseRESUMO
Mild alkaline hydrolysis of the glycophosphosphingolipids of the protozoan Leptomonas samueli liberated several phosphoinositol-containing oligosaccharides (PI-oligosaccharides), which were purified by high performance anion exchange chromatography. The oligosaccharides in the resulting four fractions were characterized by methylation analysis, fast atom bombardment mass spectrometry and two-dimensional nuclear magnetic resonance spectroscopy. The oligosaccharides contain the core structure Man alpha (1-4)GlcN alpha (1-6)-myo-inositol-1-OPO3, and are substituted with 2 mol of 2-aminoethylphosphonate per mol of oligosaccharide. The nonreducing ends of the oligosaccharides were terminated by rhamnose branched neutral and acidic xylose-containing penta-, hexa-, hepta- and octasaccharides, of which the three most abundant were shown to have the structures: [formula: see text] More tentative structures are also proposed for three minor oligosaccharides.