Physicochemical, structural and rheological properties of pectin isolated from citrus canning processing water.

In order to better utilize the citrus pectin (CP) resource, the crude citrus pectin (CCP), obtained from the citrus fruit canning processing waste water, was purified by cellulose DEAE-52 column, providing neutral polysaccharide CP0 and two acidic polysaccharides (CP1 and CP3). CP1 had the highest yield among the three fractions, being 44.29%. The chemical composition, structure and morphology of these pectin components were analyzed. Monosaccharide composition analysis revealed that arabinose was the most abundant composition in these pectin samples. CCP, CP1 and CP3 were mainly composed of rhamnogalacturonan-I (RG-I) regions. Compared with CP3, CCP and CP1 had longer side chains, which are mainly consisted of arabinose. FT-IR and NMR analysis indicated that α-type glycosidic bonds are the main linkage in the four pectin components. These CP samples were found to possess different conformation, but no triple-helical conformation was observed in all these CP fractions. Scanning electron microscopy revealed that CCP, CP1 and CP3 all had irregular sheet-like structures and partly porous structures. The four pectin components showed the characteristics of non-Newtonian fluids and possessed good viscoelasticity. Due to these properties, the pectin might have potential application in food industry as food thickening agent.

Extraction and characterization of xylan from sugarcane tops as a potential commercial substrate.

Xylan is the major hemicellulose present in sugarcane stem secondary cell walls. Xylan is composed of xylose backbone with a high degree of substitutions, which affects its properties. In the present study, the xylan from sugarcane tops (SCT) was extracted and characterized. Compositional analysis of xylan extracted from SCT (SCTx) displayed the presence of 74% of d-xylose residues, 16% of d-glucuronic acid residues and 10% of l-arabinose. High performance size exclusion chromatographic analysis of SCTx displayed a single peak corresponding to a molecular mass of ∼57 kDa. The Fourier transform infrared spectroscopic analysis of SCTx displayed the peaks corresponding to those obtained from commercial xylan. FESEM analysis of SCTx showed the granular and porous surface structure. Differential thermogravimetric analysis (DTG) of SCTx displayed two thermal degradation temperatures (Td) of 228°C, due to breakdown of the side chains of glucuronic acid and arabinose and 275°C, due to breakdown of xylan back bone. The presence of arabinose and glucuronic acid as a side chains was confirmed by the DTG and thermogravimetric analysis. The CHNS analysis of SCTx showed the presence of only carbon and hydrogen supporting its purity. The recombinant xylanase (CtXyn11A) from Clostridium thermocellum displayed a specific activity of 1394 ± 51 U/mg with SCTx, which was higher than those with commercial xylans. The thin layer chromatography and electrospray ionization mass spectroscopy analyses of CtXyn11A hydrolysed SCTx contained a series of linear xylo-oligosaccharides ranging from degree of polymerization 2-6 and no substituted xylo-oligosaccharides because of the endolytic activity of enzyme. The extracted xylan from SCT can be used as an alternative commercial substrate and for oligo-saccharide production.

Fractionation, structural characteristics and immunomodulatory activity of polysaccharide fractions from asparagus (Asparagus officinalis L.) skin.

The physicochemical properties, structural features and structure-immunomodulatory activity relationship of pectic polysaccharides from the white asparagus (Asparagus officinalis L.) skin were systematically studied. Using sequential ethanol precipitation, five sub-fractions namely WASP-40, WASP-50, WASP-60, WASP-70 and WASP-80 with distinct degree of esterification (DE) and molecular weight (Mw) were obtained. The Mw and DE values were decreased with the increase of the ethanol concentrations. Structurally, although 4-α-D-GalpA was the dominant sugar residue in all fractions, the molar ratios were decreased, whereas other sugar residues including arabinose- and mannose-based sugar residues overall increased with the increase of ethanol concentration. In addition, the effects of sub-fractions on the RAW 264.7 cells indicated that pectic polysaccharides with the higher DE value showed a stronger immunomodulatory activity. Moreover, the structure-activity relationship was also discussed in this study, which extends the value-added application of asparagus and its processing by-products.

Microwave-assisted extraction of arabinan-rich pectic polysaccharides from melon peels: Optimization, purification, bioactivity, and techno-functionality.

The effects of water to solids ratio (WSR, 10-30 mL/g), power (180-540 W), and irradiation time (IT, 5-15 min) in microwave-assisted extraction (MAE) were optimized to extract polysaccharides from melon peels (PMP). The maximum extraction yield (32.81 %) was obtained under 20.94 mL/g WSR, 414.4 W power, and 12.75 min IT. The main monosaccharide composition of purified PMP with an average molecular weight of 5.71 × 104 kDa were d-galacturonic acid, arabinose, glucose, and galactose. An ascending dose-dependent antiradical and antioxidant behavior for PMP (0-5.0 mg/mL) was found. The initial foaming capacity (38.6-110.3 %) and foaming stability (5.2-65.2 %) were significantly increased as a function of PMP concentration (1.0-5.0 %), while they reduced by increasing the mixing time (p < 0.05). The highest emulsifying activity index (44.1 m2/g) and emulsifying stability (69.3 %) at 5.0 % PMPs were determined. PMP gels with FTIR-identified functional groups can be formulated in new gluten-free functional products.

Ultrafiltration isolation, structures and anti-tumor potentials of two arabinose- and galactose-rich pectins from leaves of Aralia elata.

Two novel arabinose- and galactose-rich pectic polysaccharides, AELP-B5 (Mw, 4.25 × 104 g/mol) and B6 (Mw, 1.56 × 104 g/mol), were rapidly obtained from the leaves of Aralia elata (Miq.) Seem. with anion resin and sequenced ultrafiltration membrane columns. The structural backbone and branched chains of AELP-B5 and B6 were preliminarily elucidated by mild acid hydrolysis with HILIC-ESI--MS/MS. The planar structures and spatial configurations were further identified using UPLC-QDa and GC-MS for compositions, Smith degradation and methylation analysis, FT-IR, NMR (1H/13C, DEPT, HSQC, HMBC, COSY, NOESY and TOCSY) and SEC-MALLS-RID. (1) AELP-B5 possessed →4GalA1→ as smooth regions (HG) and a repeating disaccharide moiety of →4GalA1→2Rha1→ as hairy regions (RG-I) with a 1:5 molar ratio, whereas AELP-B6 had a distinguishing 1:1 molar ratio between the HG and RG-I; (2) complex side chains were constituted of T-α-Araf, 1,3-α-Araf, 1,5-α-Araf, T-ß-Galp, 1,3-ß-Galp, 1,4-ß-Galp, 1,6-ß-Galp, 1,3,4-ß-Galp and 1,3,4,6-ß-Galp connected at C-4 of the rhamnosyl units in RG-I of AELP-B5 and B6; and (3) both possessed highly branched and compact coil conformations. The CCK-8 assay illustrated that AELP-B6 possessed higher cytotoxicity against HepG2 and HT-29 than that of AELP-B5. Surface plasmon resonance showed the binding affinity of AELP-B6 to galectin-3 (6.488 × 10-5 M) was about 10 times stronger than that of AELP-B5 (4.588 × 10-4 M). The above findings provide a molecular structure and bioactivity basis for future potential applications of AELP in the food and medical industries.

Composition, physicochemical properties, and anti-fatigue activity of water-soluble okra (Abelmoschus esculentus) stem pectins.

Okra, Abelmoschus esculentus (L.) Moench, an annual herbaceous plant, is widely distributed in tropical and subtropical regions. Water-soluble pectic hydrocolloids from okra stems (HOS) were extracted and purified using polydivinylbenzene HP-20 resins. The sugar composition of the purified HOS with an weight-average molecular weight of 178.4 ± 2.1 kDa and a polydispersity index of 1.02 ± 0.02 contained galacturonic acid (34%), galactose (31%), rhamnose (21%), arabinose (4.2%), glucuronic acid (2.5%), xylose (1.2%), and other monosaccharides (6.1%) by weight. Its favorable rheological behaviors were evident on relatively higher concentrations (20, 25, and 30 mg/mL) and moderately lower pH levels (3 and 5) of HOS. The anti-fatigue experiments in vivo demonstrated that a high dose of HOS (450 mg/kg feed) prolonged the exhaustive swimming time of mice, significantly induced an increase in blood glucose and glycogen, and decreased lactic acid and serum urea nitrogen levels. HOS digestion in vivo was fairly conducive to the improvement of energy storage capacity and renal function for physically induced fatigue, compared with the conventional herbal supplement Panax quinquefolium. Accordingly, HOS exhibits potential for reutilization of okra stem waste.

Extraction, characterisation and antioxidant activity of polysaccharides from Chinese watermelon.

Extraction and antioxidant activity of polysaccharides from the Chinese watermelon was investigated. The polysaccharides were obtained by hot water extraction, ethanol precipitation, and deproteinization with HCl, respectively. The molecular weight was 3.02 × 104. It showed by high performance liquid chromatography (HPLC) and TLC that Chinese watermelon polysaccharides consisted of six monosaccharides, namely glucose, galactose, mannose, xylose, arabinose, and rhamnose. The polysaccharides contained the ß-glycosidic bond. Moreover, it was proved that the polysaccharides had high scavenging ability to superoxide anions.

Enantioresolution and quantification of monosaccharides by comprehensive two-dimensional gas chromatography.

This work presents the development of a simple and efficient analytical protocol for the direct enantioselective resolution of sugars. A racemic mixture of the C3 sugar d,l-glyceraldehyde and the C5 monosaccharides d,l-arabinose, d,l-ribose, d,l-xylose, and d,l-lyxose was subjected to derivatization with trifluoroacetic anhydride, and corresponding derivatives were separated on a ß-cyclodextrin column with excellent resolution factors. Even though each aldopentose shows beside the linear form four predominant cyclic hemiacetals being the α- and ß-furanose along with the α- and ß-pyranose, we show that the overall enantiomeric excess of each compound can be precisely determined. Moreover, the measured detection limit for derivatized aldopentoses ranges from 0.015 to 0.019pmol on the column, while the quantification limit varies from 0.5 to 0.64pmol on the column.

Optimization Extraction, Preliminary Characterization and Antioxidant Activities of Polysaccharides from Semen Juglandis.

The optimization extraction process, preliminary characterization and antioxidant activities of polysaccharides from Semen Juglandis (SJP) were studied in this paper. Based on the Box-Behnken experimental design and response surface methodology, the optimal extraction conditions for the SJP extraction were obtained as follows: temperature 88 °C, extraction time 125 min and ratio of liquid to solid 31 mL/g. Under these conditions, experimental extraction yield of SJP was (5.73 ± 0.014)% (n = 5), similar to the predicted value of 5.78%. Furtherly, the purified SJP obtained from SJP extract by DEAE-52 and Sephacryl S-100 chromatography was analyzed to be rhamnose, galacturonic acid, galactose, arabinose and fucose in the molar ratio of 1:6.34:1.38:3.21:1.56. And the weight-average molecular weight and radius of gyration of the purified SJP in 0.1 M NaCl were determined to be 2.76 × 104 g/mol and 122 nm by SEC-MALLS, respectively. More importantly, it exhibited appreciable antioxidant activities compared to the standard Vc, such as DPPH radical scavenging activity (IC50 0.21 mg/mL), strong reducing power, ABTS radical scavenging activity (IC50 0.29 mg/mL), and hydroxyl radical scavenging activity (IC50 0.38 mg/mL). These results indicate that SJP may be useful for developing functional health products or natural antioxidant.

Pretreatment of Sugar Beet Pulp with Dilute Sulfurous Acid is Effective for Multipurpose Usage of Carbohydrates.

Sulfurous acid was used for pretreatment of sugar beet pulp (SBP) in order to achieve high efficiency of both extraction of carbohydrates and subsequent enzymatic hydrolysis of the remaining solids. The main advantage of sulfurous acid usage as pretreatment agent is the possibility of its regeneration. Application of sulfurous acid as hydrolyzing agent in relatively low concentrations (0.6-1.0 %) during a short period of time (10-20 min) and low solid to liquid ratio (1:3, 1:6) allowed effective extraction of carbohydrates from SBP and provided positive effect on subsequent enzymatic hydrolysis. The highest obtained concentration of reducing substances (RS) in hydrolysates was 8.5 %; up to 33.6 % of all carbohydrates present in SBP could be extracted. The major obtained monosaccharides were arabinose and glucose (9.4 and 7.3 g/l, respectively). Pretreatment of SBP with sulfurous acid increased 4.6 times the yield of glucose during subsequent enzymatic hydrolysis of remaining solids with cellulase cocktail, as compared to the untreated SBP. Total yield of glucose during SBP pretreatment and subsequent enzymatic hydrolysis amounted to 89.4 % of the theoretical yield. The approach can be applied directly to the wet SBP. Hydrolysis of sugar beet pulp with sulfurous acid is recommended for obtaining of individual monosaccharides, as well as nutritional media.

Centrifugal partition chromatography in a biorefinery context: Separation of monosaccharides from hydrolysed sugar beet pulp.

A critical step in the bioprocessing of sustainable biomass feedstocks, such as sugar beet pulp (SBP), is the isolation of the component sugars from the hydrolysed polysaccharides. This facilitates their subsequent conversion into higher value chemicals and pharmaceutical intermediates. Separation methodologies such as centrifugal partition chromatography (CPC) offer an alternative to traditional resin-based chromatographic techniques for multicomponent sugar separations. Highly polar two-phase systems containing ethanol and aqueous ammonium sulphate are examined here for the separation of monosaccharides present in hydrolysed SBP pectin: l-rhamnose, l-arabinose, d-galactose and d-galacturonic acid. Dimethyl sulfoxide (DMSO) was selected as an effective phase system modifier improving monosaccharide separation. The best phase system identified was ethanol:DMSO:aqueous ammonium sulphate (300gL(-1)) (0.8:0.1:1.8, v:v:v) which enabled separation of the SBP monosaccharides by CPC (200mL column) in ascending mode (upper phase as mobile phase) with a mobile phase flow rate of 8mLmin(-1). A mixture containing all four monosaccharides (1.08g total sugars) in the proportions found in hydrolysed SBP was separated into three main fractions; a pure l-rhamnose fraction (>90%), a mixed l-arabinose/d-galactose fraction and a pure d-galacturonic acid fraction (>90%). The separation took less than 2h demonstrating that CPC is a promising technique for the separation of these sugars with potential for application within an integrated, whole crop biorefinery.

Simultaneous Enantioseparation of Aldohexoses and Aldopentoses Derivatized With L-Tryptophanamide by Reversed Phase HPLC Using Butylboronic Acid as a Complexation Reagent of Monosaccharides.

Three aldohexoses, glucose, galactose, and mannose, and three aldopentoses, arabinose, xylose, and ribose, were derivatized with L-tryptophanamide (L-TrpNH2 ) under alkaline conditions. Using a basic mobile phase (pH 9.2), the three aldohexoses or the three aldopentoses were simultaneously enantioseparated, respectively, but all the six monosaccharides could not be simultaneously enantioseparated. A large amount of nonreacted L-TrpNH2 was detected after the derivatized monosaccharides. In order to widen the separation window, a large portion of nonreacted L-TrpNH2 could be eliminated by liquid-liquid extraction with ethylacetate, and elution order of the derivatized monosaccharides and nonreacted L-TrpNH2 was found to be reversed using a neutral mobile phase. All of the six monosaccharides were simultaneously enantioseparated by reversed phase high-performance liquid chromatography (HPLC) using InertSustainSwift C18 column (4.6 mm i.d. × 150 mm) and a mobile phase containing 180 mM phosphate buffer (pH 7.6), 1.5 mM butylboronic acid, and 5% acetonitrile at 40 °C. Nomenclature of D and L for monosaccharides is based on the configurations of the asymmetric C4 center for aldopentoses and C5 center for aldohexoses. It was found that the enantiomer elution order of these six monosaccharides and fucose in the proposed method conformed to be the absolute configuration of the C2 center.

Carbohydrate composition of peach palm (Bactris gasipaes Kunth) by-products flours.

The flours obtained from peach palm by-products are rich in dietary fiber (62-71%) and they can be used as food ingredients. The aim of this work was to investigate the carbohydrate composition of the flours processed from the residual parts (stem and median sheath) of a hearts-of-palm industry. The flours were fractionated, based on their solubility, whose monomeric compounds were determined. The fraction containing mostly cellulose (S5) was the most abundant (26-28%), followed by the sum of fractions (S2, 53, S4) extracted with alkaline solutions (21-22%). The S1 fraction contained the highest percentage of uronic acids, which characterizes the presence of pectin. Xylose and arabinose were found in high proportion in S2 and S3 fractions. The S4 and S5 fractions, rich in glucose, were the main portion of the cell wall material and correspond to the insoluble fraction of the dietary fiber.

Comparing the performance of Miscanthus x giganteus and wheat straw biomass in sulfuric acid based pretreatment.

The objective of this study was to assess and compare the suitability of Miscanthus x giganteus and wheat straw biomass in dilute acid catalyzed pretreatment. Miscanthus and wheat straw were treated in a dilute sulfuric acid/steam explosion pretreatment. As a result of combining dilute sulfuric acid- and steam explosion pretreatment the hemicellulose hydrolysis yields (96% in wheat straw and 90% in miscanthus) in both substrates were higher than reported in literature. The combined severity factor (=CSF) for optimal hemicellulose hydrolysis was 1.9 and 1.5 in for miscanthus and wheat straw respectively. Because of the higher CSF value more furfural, furfuryl alcohol, 5-hydroxymethylfurfural and acetic acid was formed in miscanthus than in wheat straw pretreatment.

Extraction optimization, preliminary characterization and immunological activity of polysaccharides from figs.

Complex enzyme extraction (CEE), purification, characterization of fig polysaccharides (FPs) from dried figs were investigated. Orthogonal experiment was used to optimize the concentration of cellulose, pectinase and papain. Response surface methodology (RSM) was employed to optimize extraction conditions. The optimum extraction conditions were: enzyme concentration of 1.5%, 1.5%, 0.5% (wt%) of pectinase, papain, cellulose, ratio of water to raw material 40.3 mL/g, extraction time 54.1 min, temperature 34.15 °C and pH 3.8. Under these conditions, the experimental yield was 7.98 ± 0.17%. Two homogeneous heteropolysaccharides (FPs-1-1, FPs-2-1) were purified by DEAE-Sepharose and Sephadex G-200 chromatography, which were composed of rhamnose, arabinose, xylose, mannose, glucose and galactose with molecular weight of 1.52 × 10(6) and 4.75 × 10(5)Da, respectively. The bioactivity assay showed that FPs-1-1 and FPs-2-1 could more significantly enhance splenic lymphocyte proliferation, phagocytosis and NO production of macrophages, could be explored as potential immunopotentiating agent for use in functional food or medicine.

Optimization of alkaline extraction and bioactivities of polysaccharides from rhizome of Polygonatum odoratum.

The present study is to explore the optimal extraction parameters, antioxidant activity, and antimicrobial activity of alkaline soluble polysaccharides from rhizome of Polygonatum odoratum. The optimal extraction parameters were determined as the following: NaOH concentration (A) 0.3 M, temperature (B) 80 °C, ratio of NaOH to solid (C) 10-fold, and extraction time (D) 4 h, in which ratio of NaOH to solid was a key factor. The order of the factors was ratio of NaOH to solid (fold, C) > extraction temperature (°C, B) > NaOH concentration (M, A) > extraction time (h, D). The monosaccharide compositions of polysaccharides from P. odoratum were rhamnose, mannose, xylose, and arabinose with the molecular ratio of 31.78, 31.89, 11.11, and 1.00, respectively. The reducing power, the 1, 1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging rate, the hydroxyl radicals scavenging rate, and the inhibition rate to polyunsaturated fatty acid (PUFA) peroxidation of the alkaline soluble polysaccharides from P. odoratum at 1 mg/mL were 9.81%, 52.84%, 19.22%, and 19.42% of ascorbic acid at the same concentration, respectively. They also showed antimicrobial activity against pathogenic bacteria Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, and Escherichia coli.

Comparison of physicochemical properties and immunomodulatory activity of polysaccharides from fresh and dried litchi pulp.

Drying is commonly used for preservation and processing of litchi. However, its polysaccharide structure may be altered by the drying process, resulting in biological activity changes. Polysaccharides from fresh and dried litchi pulp (denoted as LPF and LPD, respectively) were isolated, investigated by GC-MS, GPC and UV/IR spectrum analysis and their antitumor and immunomodulatory activities were evaluated in vitro. LPD, the molecular weight of which was lower than that of LPF, contained more protein, uronic acid, arabinose, galactose and xylose. Compared with LPF, LPD exhibited a higher inhibitory effect on the proliferation of HepG2, Hela and A549 cells from 50-750 µg/mL. LPD was also a better stimulator of spleen lymphocyte proliferation, NK cells cytotoxicity and macrophage phagocytosis from 50-400 µg/mL. In summary, drying could change the physicochemical properties and enhance the bioactivity of polysaccharides from litchi pulp. This finding is supported by the fact that dried litchi pulps are used in Traditional Chinese Medicine.

[Applicability of a natural swelling matrix as the propellant of osmotic pump tablets].

The purpose of this study is to investigate the applicability of a natural swelling matrix derived from boat-fruited sterculia seed (SMS) as the propellant of osmotic pump tablets. The sugar components, static swelling, water uptake and viscosity of SMS were determined and compared with that of polythylene oxide (WSR-N10 and WSR-303). Both ribavirin and glipizide were used as water-soluble and water-insoluble model drugs. Then, the monolayer osmotic pump tablets of ribavirin and the bilayer osmotic pump tablets of glipizide were prepared using SMS as the osmotically active substance and propellant. SMS was mainly composed of rhamnose, arabinose, xylose and galactose and exhibited relatively high swelling ability. The area of the disintegrated matrix tablet was 20.1 times as that at initial after swelling for 600 s. SMS swelled rapidly and was fully swelled (0.5%) in aqueous solution with relative low viscosity (3.66 +/- 0.03) mPa x s at 25 degrees C. The monolayer osmotic pump tablets of ribavirin and the bilayer osmotic pump tablets of glipizide using SMS as propellant exhibited typical drug release features of osmotic pumps. In conclusion, the swelling matrix derived from boat-fruited sterculia seed, with low viscosity and high swelling, is a potential propellant in the application of osmotic pump tablets.

Steroids glycosylated with both D- and L-arabinoses from the South China Sea gorgonian Dichotella gemmacea.

Three new 19-hydroxy steroidal glycosides, namely, junceellosides E-G (2-4), were isolated together with the known analogue junceelloside C (1) from the South China Sea gorgonian Dichotella gemmacea. The structures of these compounds were elucidated by a combination of detailed spectroscopic analyses, chemical methods, and comparison with reported data. These glycosides are found to have sugar moieties of both ß-l- and ß-d-arabinopyranoses by HPLC analysis of their thiocarbamoyl-thiazolidine derivatives and those of authentic d- and l-arabinoses, leading to the structure revision of junceelloside C (1). This is the first report of steroidal glycosides from the gorgonian D. gemmacea and the first report of glycosides with ß-l-arabinopyranose from marine sources.

Polysaccharide isolated from Angelica sinensis inhibits hepcidin expression in rats with iron deficiency anemia.

A novel polysaccharide named Angelica sinensis polysaccharide (ASP) was obtained from the powdered and defatted roots of A. sinensis (Oliv.) Diels. The molecular weight of ASP was determined to be 78 kDa and was 95.0% sugars consisting of mostly arabinose, glucose, and galactose with a molar ratio of 1:5.68:3.91. A previous study indicated that ASP may increase plasma iron levels by suppressing the expression of hepcidin, a negative regulator of body iron metabolism, in the liver. The present study aims to clarify the inhibitory effect of ASP on hepcidin expression in rat models of iron deficiency anemia (IDA), and clarify the mechanisms involved. It was demonstrated that ASP significantly reduced hepcidin expression by inhibiting the expression of mothers against decapentaplegic protein 4 (SMAD4) in liver and stimulating the secretion of erythropoietin, which further downregulated hepcidin by repressing CCAAT/enhancer-binding protein α (C/EBPα) and the phosphorylation of signal transducer and activator of transcription 3/5. The results indicate that ASP can suppress the expression of hepcidin in rats with IDA, and may be useful for the treatment of IDA.