Structural differences of polysaccharides from Astragalus before and after honey processing and their effects on colitis mice.

Honey-processed Astragalus is a dosage form of Radix Astragali processed with honey, which exhibits better efficacy of tonifying Qi than the raw product. Polysaccharides are its main water-soluble active components. This work was designed to study the structural differences of homogeneous honey-processed Astragalus polysaccharides (HAPS3a) and Astragalus polysaccharides (APS3a) and their effects on colitis mice. The results showed that HAPS3a (Mw = 2463.5 kDa) and APS3a (Mw = 3373.2 kDa) differed in molecular weight, monosaccharide compositions, glycosidic bonds and degree of branching (DB). Notably, the molar ratios of galactose and galacturonic acid in HAPS3a were 22.66% and 33.24%, while those in APS3a were 11.87% and 49.55%, respectively. The uronic acid residues 1,4-ß-GalpA and 1,6-α-GlcpA of the backbone in APS3a were converted into the corresponding neutral residues in HAPS3a after honey processing. The different DB of HAPS3a (15.35%) and APS3a (25.13%) suggested that the chain conformation became smoother. The anti-inflammatory effects on colitis mice revealed that HAPS3a exhibited better effects than APS3a by protecting intestinal mucosa, regulating the expression of cytokines and influencing microbiota diversity. Taken together, the differences in anti-inflammatory activity might be related to structural differences caused by honey processing. Our findings have laid a foundation for the processing mechanism of Astragalus.

Ultrafiltration isolation, physicochemical characterization, and antidiabetic activities analysis of polysaccharides from green tea, oolong tea, and black tea.

Both fermentation degree and preparation method of polysaccharides could influence the bioactivity of tea polysaccharides. The aim of this study was to compare the physicochemical characterization and biological activities of the polysaccharides isolated by ultrafiltration method from three kinds of tea (green tea, oolong tea, and black tea). The bioactivities of tea polysaccharide fractions were compared from four aspects, including antioxidant activities, antiglycation activities, α-glucosidase inhibitory capability, and hypoglycemic effects on L6 myotubes. Results showed that six polysaccharides (GTPS1, GTPS2, OTPS1, OTPS2, BTPS1, and BTPS2) had different contents of neutral sugar and uronic acid, and they showed different morphologies. Six polysaccharides were composed of the seven monosaccharides with different molar ratios. BTPS1 exhibited the highest DPPH scavenging activity and hydroxyl radical scavenging activity (P < 0.05), and BTPS1 also showed the strongest antiglycation inhibitory effects (P < 0.05). BTPS1 and BTPS2 showed strong inhibitory capacity on α-glucosidase and hypoglycemic effects in L6 skeletal muscle cells. The result suggested that the degree of fermentation of tea could improve their bioactivities (BTPS > OTPS >GTPS), and TPS1 with smaller molecular weight distribution showed higher bioactivities than TPS2. This study can provide a scientific foundation for the application of tea polysaccharides and related functional products.

Synthesis and characterization of porous tree gum grafted copolymer derived from Prunus cerasifera gum polysaccharide.

Porous grafted copolymer with excellent thermal stability and swelling capacity was synthesized from water soluble Prunus cerasifera gum polysaccharide (PG) and acrylamide (AM). The monosaccharide compositions and the structure of Prunus cerasifera tree gum were detected by a high-performance anion exchange chromatography (HPAEC) system and 1H NMR and 13C NMR, and the obtained PG-AM copolymer was characterized by Fourier transform infrared (FT-IR), scanning electron microscope (SEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. The results indicated that the water soluble polysaccharides obtained from Prunus cerasifera tree gum were mainly composed of l-arabinose (39.78%) and d-galactose (40.59%) with minor amount of xylose, mannose and uronic acids. The maximum percent and the grafting efficiency of grafting acrylamide (AM) onto PG to form PG-AM were obtained by copolymerization between polysaccharide and 3 times (weight) acrylamide with 3 mmol/L potassium persulfate initiator at 50 °C for 1 h. In addition, lots of isolated and conjoint pores were observed in the prepared PG-AM materials, with a diameters distribution between 2 and 10 µm. Compared with PG, the synthesized copolymer PG-AM showed an excellent performance in thermal stability and swelling capacity. The detailed structural characteristic together with excellent thermal stability and swelling properties will benefit efficient utilization of the synthesized copolymer as a precursor for preparation of large-scale environmentally friendly advanced materials with various potential applications.

Blueberry Pectin Extraction Methods Influence Physico-Chemical Properties.

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.

Chemical composition of barks from Quercus faginea trees and characterization of their lipophilic and polar extracts.

The bark from Quercus faginea mature trees from two sites was chemically characterized for the first time. The barks showed the following composition: ash 14.6%, total extractives 13.2%, suberin 2.9% and lignin 28.2%. The polysaccharides were composed mainly of glucose and xylose (50.3% and 35.1% of all monosaccharides respectively) with 4.8% of uronic acids. The suberin composition was: ω-hydroxyacids 46.3% of total compounds, ɑ,ω-alkanoic diacids 22.3%, alkanoic acids 5.9%, alkanols 6.7% and aromatics 6.9% (ferulic acid 4.0%). Polar extracts (ethanol-water) had a high phenolic content of 630.3 mg of gallic acid equivalents (GAE)/g of extract, condensed tannins 220.7 mg of catechin equivalents (CE)/g extract, and flavonoids 207.7 mg CE/g of extract. The antioxidant activity was very high corresponding to 1567 mg Trolox equivalents/g of extract, and an IC50 of 2.63 µg extract/ml. The lipophilic extracts were constituted mainly by glycerol and its derivatives (12.3% of all compounds), alkanoic acids (27.8%), sterols (11.5%) and triterpenes (17.8%). In view of an integrated valorization, Quercus faginea barks are interesting sources of polar compounds including phenols and polyphenols with possible interesting bioactivities, while the sterols and triterpenes contained in the lipophilic extracts are also valuable bioactive compounds or chemical intermediates for specific high-value market niches, such as cosmetics, pharmaceuticals and biomedicine.

Extraction of pectin from ponkan (Citrus reticulata Blanco cv. Ponkan) peel: Optimization and structural characterization.

A central composite experimental design was used to evaluate the influence of pH, extraction time and liquid:solid ratio on the yield and uronic acid content of the pectin from ponkan peel. The response surface methodology showed that the yield is positively influenced by lower pHs, longer extraction times and higher liquid:solid ratio, whereas the uronic acid content decreases with increasing extraction time. The conditions that resulted in the highest yield and highest uronic acid content were defined as pH 1.6, extraction time of 100 min and liquid:solid ratio of 36 mL/g. The pectin obtained under these conditions (PPOP) had an experimental yield of 25.6%, below the predicted theoretical value despite the good fit of the model (R2 = 0.96) and the galacturonic acid content was 84.5%, in close agreement with the predicted theoretical value. PPOP was composed mainly of a homogalacturonan with degree of methyl esterification of 85.7% and a rhamnogalacturonan I region mainly branched by galactans. In addition, PPOP had a very low degree of acetylation (0.1%) and average molar mass of 80,650 g/mol, determined by light scattering. The results showed that ponkan peel may be used as a source of citrus pectin in the regions where this species is cultivated.

Quantification of anti-nutritional factors and their correlations with protein and oil in soybeans.

Soybeans contain about 30% carbohydrate, mainly consisting of non-starch polysaccharides (NSP) and oligosaccharides. NSP are not hydrolyzed in the gastrointestinal tract of monogastric animals. These NSP negatively affect the development of these animals, especially the soluble fraction. This work aimed to establish a method to quantify NSP in soybeans, using high performance liquid chromatography (HPLC), and to estimate correlations between NSP, oligosaccharides, protein and oil. Sucrose, raffinose + stachyose, soluble and insoluble NSP contents were determined by HPLC. Oil and protein contents were determined by near-infrared spectroscopy (NIRS). The soluble PNAs content showed no significant correlation with protein, oil, sucrose and raffinose + stachyose contents, but oligosaccharides showed a negative correlation with protein content. These findings open up the possibility of developing cultivars with low soluble NSP content, aiming to develop feed for monogastric animals.

Quantification of anti-nutritional factors and their correlations with protein and oil in soybeans

ABSTRACT Soybeans contain about 30% carbohydrate, mainly consisting of non-starch polysaccharides (NSP) and oligosaccharides. NSP are not hydrolyzed in the gastrointestinal tract of monogastric animals. These NSP negatively affect the development of these animals, especially the soluble fraction. This work aimed to establish a method to quantify NSP in soybeans, using high performance liquid chromatography (HPLC), and to estimate correlations between NSP, oligosaccharides, protein and oil. Sucrose, raffinose + stachyose, soluble and insoluble NSP contents were determined by HPLC. Oil and protein contents were determined by near-infrared spectroscopy (NIRS). The soluble PNAs content showed no significant correlation with protein, oil, sucrose and raffinose + stachyose contents, but oligosaccharides showed a negative correlation with protein content. These findings open up the possibility of developing cultivars with low soluble NSP content, aiming to develop feed for monogastric animals.

Physicochemical, functional, and biological properties of water-soluble polysaccharides from Rosa roxburghii Tratt fruit.

Water-soluble polysaccharides (RTFP) were extracted from Rosa roxburghii Tratt fruit by hot water method. The physicochemical, functional, and hypoglycemic properties of RTFP were investigated. The results revealed that RTFP mainly contained carbohydrates (63.79 ±â€¯0.73%, g/g), uronic acids (14.8 ±â€¯0.06%, g/g), and proteins (4.10 ±â€¯0.58%, g/g). RTFP was composed of arabinose, galactose, glucose, mannose, xylose, and fucose with molar percentages of 33.8, 37.3, 20.7, 1.74, 3.43, and 2.95%, respectively. Functional analyses indicated that RTFP had good oil-holding capacity, foaming properties, and emulsifying capacity. The rheological results showed that RTFP exhibited typical shear-thinning behavior and viscoelastic properties influenced by sample concentration, temperature and inorganic salt. Additionally, RTFP exhibited favorable inhibitory activities against α-glucosidase in a mixed inhibition type, and against α-amylase in an uncompetitive inhibition type. These results suggest that RTFP can be exploited as a multi-functional additive or hypoglycemic agent in foods, pharmaceuticals and cosmetics.

Husk Tomato (Physalis ixocarpa Brot.) Waste as a Promising Source of Pectin: Extraction and Physicochemical Characterization.

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.

Extraction and characterization of three polysaccharides extracted from Opuntia ficus indica cladodes.

The chemical extraction and the characterization of polysaccharides from mucilage (MC), pectin (PC) and total pectic mucilage fraction (TFC) of Opuntia ficus indica cladodes as well as the evaluation of their antioxidant activities was investigated. The FTIR spectroscopic analysis revealed the presence of carboxyl and hydroxyl groups corresponding to polysaccharides. Uronic acid and the total sugar contents of PC were higher than those of TFC and MC whereas ash content of MC was considerably more important. In addition, the findings showed that all the samples had little protein content and low average molecular weight compared to the results mentioned in literature. Furthermore, MC reached not only the highest water (WHC) and oil holding (OHC) capacities (7.81g/g and 1.34g/g, respectively) but also the highest antioxidant properties (DPPH and ABTS scavenging activities, ß-carotene bleaching inhibition activity and reducing power). However, PC had the strongest emulsifying and foaming properties. As for TFC, it had low WHC, OHC and emulsifying properties whereas it had higher foaming properties than MC and greater antioxidant properties compared to PC. These outcomes can encourage the use of PC as a surfactant and MC and TFC as natural antioxidants in food and pharmaceutical industries.

Pectic type II arabinogalactans from starfruit (Averrhoa carambola L.).

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 (1→3), (1→6) and (1→3,6)-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.

Modification of deoiled cumin dietary fiber with laccase and cellulase under high hydrostatic pressure.

In this study, we evaluated the effects of high hydrostatic pressure (HHP) and enzyme (laccase and cellulase) treatment on the structural, physicochemical, and functional properties and antioxidant activity of deoiled cumin dietary fiber (DF). HHP-enzyme treatment increased the contents of soluble dietary fiber (SDF) (30.37 g/100g), monosaccharides (except for glucose), uronic acids, and total polyphenol. HHP-enzyme treatment altered the honey-comb structure of DF and generated new polysaccharides. DF modified by HHP-enzyme treatment exhibited improved water retention capacity (10.02 g/g), water swelling capacity (11.19 mL/g), fat and glucose absorption capacities (10.44 g/g, 22.18-63.54 mmol/g), α-amylase activity inhibition ration (37.95%), and bile acid retardation index (48.85-52.58%). The antioxidant activity of DF was mainly correlated to total polyphenol content (R=0.8742). Therefore, DF modified by HHP-enzyme treatment from deoiled cumin could be used as a fiber-rich ingredient in functional foods.

Extraction optimization, characterization and antioxidant activity in vitro of polysaccharides from mulberry (Morus alba L.) leaves.

Extraction optimization, characterization and antioxidant activity in vitro of polysaccharides from mulberry leaves (MLP) were investigated in the present study. The optimal extraction conditions with an extraction yield of 10.0 ± 0.5% for MLP were determined as follows: extraction temperature 92 °C, extraction time 3.5h and ratio (v/w, mL/g) of extraction solvent (water) to raw material 34. Two purified fractions, MLP-3a and MLP-3b with molecular weights of 80.99 and 3.64 kDa, respectively, were obtained from crude MLP by chromatography of DEAE-Cellulose 52 and Sephadex G-100. Fourier transform-infrared spectroscopy revealed that crude MLP, MLP-3a and MLP-3b were acidic polysaccharides. Furthermore, crude MLP and MLP-3a had more complicated monosaccharide compositions, while MLP-3b had a relatively higher content of uronic acid. Crude MLP, MLP-3a and MLP-3b exhibited potent Fe(2+) chelating power and scavenging activities on 1,1-diphenyl-2-picrylhydrazyl, hydroxyl, superoxide and 2,2'-azinobis-(3-ethyl-benzothiazolin-6-sulfonic acid) radicals. The results suggested that MLP could be explored as natural antioxidant.

Comparative study of two table grape varieties with contrasting texture during cold storage.

Postharvest softening of grape berries is one of the main problems affecting grape quality during export. Cell wall disassembly, especially of pectin polysaccharides, has been commonly related to fruit softening, but its influence has been poorly studied in grapes during postharvest life. In order to better understand this process, the Thompson seedless (TS) variety, which has significantly decreased berry texture after prolonged cold storage, was compared to NN107, a new table grape variety with higher berry firmness. Biochemical analysis revealed a greater amount of calcium in the cell wall of the NN107 variety and less reduction of uronic acids than TS during cold storage. In addition, the activity of polygalacturonase was higher in TS than NN107 berries; meanwhile pectin methylesterase activity was similar in both varieties. Polysaccharide analysis using carbohydrate gel electrophoresis (PACE) suggests a differential pectin metabolism during prolonged cold storage. Results revealed lower pectin fragments in TS after 60 days of cold storage and shelf life (SL) compared to 30 days of cold storage and 30 + SL, while NN107 maintained the same fragment profile across all time points evaluated. Our results suggest that these important differences in cell wall metabolism during cold storage could be related to the differential berry firmness observed between these contrasting table grape varieties.

Characterization, antioxidant and immunomodulatory activities of polysaccharides from Prunella vulgaris Linn.

Water-soluble polysaccharides from Prunella vulgaris Linn (P. vulgaris) were fractionated using DEAE-Sepharose fast-flow column to obtain several eluents of water (PV-P1), 0.1M NaCl (PV-P2) and 0.2M NaCl (PV-P3). Structural analyses showed that PV-P1 had a higher molecular weight and degree of branching as compared to PV-P2 and PV-P3. Tertiary structure analyses indicated that PV-P1, PV-P2 and PV-P3 did not have triple-helical conformation. PV-P2 and PV-P3 showed stronger antioxidant activities than PV-P1, as measured radical scavenging capacities. PV-P1 showed stronger immunomodulatory activities than PV-P2 and PV-P3 in term of stimulation of the production of pro-inflammatory cytokines, including nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in murine macrophage RAW 264.7 cells. PV-P1, PV-P2 and PV-P3 did not exhibit cytotoxicities against RAW 264.7 at the concentrations tested. These results suggest that P. vulgaris polysaccharides could be explored as potential antioxidant and immunomodulatory agents for the complementary medicine or functional foods.

Valorization of pomegranate peel from 12 cultivars: dietary fibre composition, antioxidant capacity and functional properties.

The dried powdered fruit peels of pomegranate (Punica granatum L.) (PomP) from 12 cultivars were used to extract and characterise their dietary fibre (DF) and to assess their functional and antioxidant properties. The total DF content varied between 33.10 and 62/100 g. The cellulose, Klason lignin, uronic acid and total neutral sugars (NS) composition of DF was: 16.53-22.71, 20.59-41.86, 13.98-23.31 and 16.88-19.66/100g, respectively. Arabinose and xylose were the most present NS with more than 60% of total NS content. The ratio of insoluble to soluble DF was around 1, reflecting the balanced composition of PomP's DF. Besides, PomP powder showed intermediate values for water- and oil-holding capacities: 2.31-3.53 and 2.80-4.05 mL/g, respectively, and strong retardation effect on the dialysis of glucose, reaching ∼60%. Also, it has been shown that most of the antioxidants can be extracted, based on the strong soluble antioxidant activity (2018-2649 µmol Trolox/g) compared to the insoluble one (13-23 µmol Trolox/g).

An acetate-hydroxide gradient for the quantitation of the neutral sugar and uronic acid profile of pectins by HPAEC-PAD without postcolumn pH adjustment.

An HPAEC-PAD method was developed and validated to quantitate seven neutral sugars and two uronic acids of hydrolyzed pectic polysaccharides without postcolumn pH adjustment. Due to a short gradient phase minimizing the ion concentrations after equilibrating the CarboPac PA20 column with sodium acetate and hydroxide, subsequent isocratic separation of the neutral sugars was characterized by almost baseline resolution of rhamnose and arabinose (1.45 ± 0.15) and xylose and mannose (1.21 ± 0.02) at their maximal concentrations. Linearity was shown (R² = 0.9975-0.9998) for the relevant ranges (0.28-30.3 µmol L⁻¹); galacturonic acid, 1.7-128 µmol L⁻¹) above the limits of detection (30-81 nmol L⁻¹; galacturonic acid, 179 nmol L⁻¹) and ∼3.8 times higher limits of quantification. Conformity of the findings for four pectins after methanolysis plus hydrolysis in trifluoroacetic acid with those of reference procedures (total uronic acids, 95-102%; total neutral sugars, 97-105%) proved the accuracy.

Effect of extraction conditions on the yield and chemical properties of pectin from cocoa husks.

Different extraction conditions were applied to investigate the effect of temperature, extraction time and substrate-extractant ratio on pectin extraction from cocoa husks. Pectin was extracted from cocoa husks using water, citric acid at pH 2.5 or 4.0, or hydrochloric acid at pH 2.5 or 4.0. Temperature, extraction time and substrate-extractant ratio affected the yields, uronic acid contents, degrees of methylation (DM) and degrees of acetylation (DA) of the extracted pectins using the five extractants differently. The yields and uronic acid contents of the extracted pectins ranged from 3.38-7.62% to 31.19-65.20%, respectively. The DM and DA of the extracted pectins ranged from 7.17-57.86% to 1.01-3.48%, respectively. The highest yield of pectin (7.62%) was obtained using citric acid at pH 2.5 [1:25 (w/v)] at 95 °C for 3.0 h. The highest uronic acid content (65.20%) in the pectin was obtained using water [1:25 (w/v)] at 95 °C for 3.0 h.

Cell wall modifications and ethylene-induced tolerance to non-chilling peel pitting in citrus fruit.

Non-chilling peel pitting (NCPP), a storage disorder resulting in the formation of depressed areas in the peel of many citrus cultivars, is reduced by ethylene treatments. We hypothesized that this effect may be associated with biochemical changes of cell wall components. Therefore, we extracted cell wall material from albedo and flavedo tissues of 'Navelate' oranges stored in air, conditioned with ethylene (2µLL(-1)) for 4 days and subsequently transferred to air, or continuously stored in an ethylene-enriched atmosphere (2µLL(-1)). Uronic acids and neutral sugars were extracted into five fractions enriched in specific wall polymers namely water-, CDTA-, Na2CO3-, and 1 and 4M KOH-soluble fractions. Pectin insolubilization was found in control fruit at long storage times. Ethylene treatments, alleviating NCPP, increased polyuronide solubility in the albedo and had a slight effect on the flavedo. Ethylene-treated fruit showed greater content of water-soluble neutral sugars and a larger proportion of hemicelluloses readily extractable with 1M KOH, with a concomitant reduction in the 4M KOH-soluble fraction. This suggests that the protective role of ethylene on NCPP is associated with an increased solubilization of the wall of albedo cells.