Improvement of simultaneous determination of neutral monosaccharides and uronic acids by gas chromatography

A Novel Pectic Polysaccharide of Jujube Pomace: Structural Analysis and Intracellular Antioxidant Activities

After extraction from jujube pomace and purification by two columns (DEAE-Sepharose Fast Flow and Sepharcyl S-300), the structure of SAZMP4 was investigated by HPGPC, GC, FI-IR, GC-MS, NMR, SEM, and AFM. Analysis determined that SAZMP4 (Mw = 28.94 kDa) was a pectic polysaccharide mainly containing 1,4-linked GalA (93.48%) with side chains of 1,2,4-linked Rha and 1,3,5-linked Ara and terminals of 1-linked Rha and 1-linked Ara, which might be the homogalacturonan (HG) type with side chains of the RG-I type, corresponding to the results of NMR. In AFM and SEM images, self-assembly and aggregation of SAZMP4 were respectively observed indicating its structural features. The antioxidant activity of SAZMP4 against H₂O₂-induced oxidative stress in Caco-2 cells was determined by activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) as well as malondialdehyde (MDA) and reactive oxygen species (ROS) levels, indicating SAZMP4 can be a natural antioxidant. Also, a better water retention capacity and thermal stability of SAZMP4 was observed based on DSC analysis, which could be applied in food industry as an additive.

Optimization of Alkali Extraction and Properties of Polysaccharides from Ziziphus jujuba cv. Residue

Ziziphus jujuba cv. Muzao is a plant widely cultivated in the Yellow River Basin of China. It has nutritional and healthcare functions, in which polysaccharides are the main components of its bio-functions. In order to make effective use of Ziziphus jujuba cv. Muzao residue resources and explore new functional food ingredients, the polysaccharide (ZJRP) from Ziziphus jujuba cv. Muzao residues were extracted by sodium hydroxide, and the optimal extraction conditions of ZJRP were obtained by the response surface method. The basic composition and antioxidant effects of ZJRP were determined. The results showed that ZJRP has significant antioxidant activity, mainly reflected in the high DPPH radical scavenging rate, which may be related to their high content of galacturonic acid and the extraction method. In addition, the rheological and thermal properties of ZJRP were respectively determined by a rheometer and differential scanning calorimetry (DSC), indicating that they have shear thinning properties and good thermal stability. Results showed that the alkaline extraction method can be used as a potential technique for extracting ZJRP with high antioxidant activity, and ZJRP can be further explored as a functional food ingredient.

Alterations in physicochemical and functional properties of buckwheat straw insoluble dietary fiber by alkaline hydrogen peroxide treatment

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The untreated IDF tended to strong antioxidant properties in vitro.

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The changes of antioxidation might be related to specific substrates.

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AHP treatment could led to redistribution of monosaccharide in IDF.

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AHP treatment could improve physicochemical properties of IDF.

To enhance the physicochemical and functional properties of insoluble dietary fiber (IDF) from buckwheat straw, we investigated the effects of alkaline hydrogen peroxide (AHP) treatment. Electron microscopy showed that the IDF had regular and compact tubes that turned into wrinkled lamellar products. After AHP treatment, X-ray diffraction indicated that the crystalline structure of the IDF was perturbed. And an undesirable decrease was observed in the content of hydroxybenzoic acid derivatives, hydroxycinnamic acid derivatives, flavonoids and the antioxidant capacity of IDF modified by AHP; however, the hydration properties (such as water holding capacity), α-amylase inhibition activity and glucose adsorption capacity of IDF were significantly enhanced by AHP. Furthermore, AHP led to a redistribution of monosaccharides in soluble dietary fiber and IDF, an interesting finding hinting at the mechanism and potential applications of AHP modification of IDF. In this study, AHP enhanced the physiological and functional properties of buckwheat straw IDF.

Strategy for Structural Elucidation of Polysaccharides: Elucidation of a Maize Mucilage that Harbors Diazotrophic Bacteria

The recruitment of a bacterial consortium by the host is a strategy not limited to animals but is also used in plants. A maize aerial root mucilage has been found that harbors nitrogen fixing bacteria that are attracted to the carbohydrate rich environment. This synbiotic relationship is facilitated by a polysaccharide, whose complicated structure has been previously unknown. In this report, we present the characterization of the maize polysaccharide by employing new analytical strategies combining chemical depolymerization, oligosaccharide sequencing, and monosaccharide and glycosidic linkage quantitation. The mucilage contains a single heterogeneous polysaccharide composed of a highly fucosylated and xylosylated galactose backbone with arabinan and mannoglucuronan branches. This unique polysaccharide structure may select for the diazotrophic community by containing monosaccharides and linkages that correspond to the glycosyl hydrolases associated with the microbial community. The elucidation of this complicated structure illustrates the power of the analytical methods, which may serve as a general platform for polysaccharide analysis in the future.

Effects of subcritical water extraction microenvironment on the structure and biological activities of polysaccharides from Lentinus edodes

In the present study, we investigated the effects of subcritical water microenvironment on the structure and biological activities of polysaccharides from Lentinus edodes. The results showed that, under different SWE conditions (100-150 °C for 15 min, and 150 °C for 10-30 min), all the polysaccharides were heteropolysaccharides and consisted of glucose, mannose and galactose with different molar ratios. In addition, FT-IR results showed that all samples were typical β-pyranose and protein-free polysaccharides. Moreover, Congo red staining and atomic force microscope (AFM) analyses showed that when the temperature was above 150 °C for 15 min, the triple-helix structure no longer existed. Furthermore, various polysaccharides had varying degrees of inhibitory effect on HepG2 cells and MCF-7 cells in vitro. These findings indicated that subcritical water microenvironment has an extremely important effect on the structure and bioactivities of polysaccharides. The polysaccharides may be extracted more effectively by changing the subcritical water microenvironment.

Revisiting monosaccharide analysis - quantitation of a comprehensive set of monosaccharides using dynamic multiple reaction monitoring

A rapid method for the quantitation of sixteen neutral and acidic monosaccharides, from both animal and plant sources was developed using ultra-high performance liquid chromatography triple quadrupole mass spectrometry (UHPLC/QqQ-MS) in dynamic multiple reaction monitoring (dMRM) mode. Monosaccharides including three pentoses (ribose, xylose, arabinose), two deoxyhexoses (rhamnose, fucose), five hexoses (fructose, mannose, allose, glucose, galactose), two hexuronic acids (glucuronic acid, galacturonic acid), and two N-acetyl-hexosamines (GlcNAc, GalNAc), were derivatized with 1-phenyl-3-methyl-5-pyrazolone (PMP), while underivatized sialic acids, Neu5Ac and Neu5Gc, were simultaneously analyzed with a 10-minute run. With the optimized UHPLC conditions, baseline separations of the isomers were achieved. The sensitivity and calibration ranges of this method were determined. The limits of detection were between femtomoles and attomoles with linear ranges spanning four to six orders of magnitude and coefficients of variation (CVs) ≤7.2%. Spiking experiments performed on a pooled fecal sample demonstrated the high accuracy of this method even when applied to samples with complicated matrices. The validated method was applied to fecal samples from an infant transitioning from breast milk to weaning foods. Major milk monosaccharides including galactose, fucose, glucose, GlcNAc, and Neu5Ac were found to be the most abundant components in the feces of milk-fed infants. PMP-derivatives of nine other monosaccharides including apiose, lyxose, altrose, talose, gulose, glucosamine, galactosamine, mannosamine, and N-acetylmannosamine (ManNAc) were also tested and could be added to the quantitation method depending on the need. The speed and sensitivity of the method makes it readily adaptable to rapid throughput analysis of monosaccharides in biological samples.

Extraction and physicochemical properties of polysaccharides from Ziziphus Jujuba cv. Muzao by ultrasound-assisted aqueous two-phase extraction

In this paper, ultrasound-assisted aqueous two-phase extraction (UAATPE) performed via a one-step procedure was applied to extract polysaccharides from Ziziphus Jujuba cv. Muzao. Using an ethanol/ammonium sulfate system as a multiphase solvent, effects of UAATPE on extraction of ZMP, such as solvent-to-material ratio, composition of aqueous two-phase system, and extraction time and temperature, were investigated using response surface methodology on basis of results of single-factor experiment. The final optimal conditions were ATPS composition: 29% ethanol and 15% (NH₄)₂SO₄, extraction time: 38min, extraction temperature: 48°C, solvent-to-material ratio: 30, and microwave power: 70W. Under these conditions, the experimental extraction yield was 8.18%. Chemical analysis revealed that ZMP were composed of rhamnose, arabinose, xylose, mannose, glucose, galactose, and galacturonic acid, at a ratio of 1.46:2.47:2.27:1.12:1.00:1.57:5.40, respectively. The structures were also characterized with UV, FTIR, and SEM. The DPPH and ABTS radical scavenging activities showed ZMP had moderately antioxidant activity.

Identifying the D-Pentoses Using Water Adduction to Lithium Cationized Molecule

A method has been developed that is capable of distinguishing an exhaustive list of underivatized D-pentoses with only a mass spectrometer. Electrospray ionization (ESI) of a solution containing a pentose and a lithium salt yields [Pentose + Li]⁺. These lithiated pentoses adduct water in a quadrupole ion trap. The reaction rate of water adduction is unique for several of the pentose isomers. Additionally, there are multiple potential gas-phase lithiation sites to form [Pentose + Li]⁺. A mixture of ions with at least one reactive (water adducting) and at least one unreactive (non-adducting) lithiation site is formed for each pentose. The water adduction reaction rate along with the unreactive fraction of lithiated pentose can be used to completely discriminate all D-pentoses. Graphical Abstract ᅟ.