Pectic Polysaccharide Fraction Research Articles

Development of a cell-based quaternary system to unveil the effect of pectic polysaccharides on oral astringency

Phenolic compounds are responsible for food unpleasant taste properties, including astringency, due to their ability to interact with salivary proteins and oral constituents. Astringency is a crucial attribute for consumer's acceptability. To fulfill the demand for both healthy and tasty food, polysaccharides raise as a good alternative to modulate astringency. In this work, a cell-based quaternary system was developed to evaluate the ability of polysaccharides to reduce the interaction between two classes of hydrolysable tannins – gallotannins (tannic acid) and ellagitannins (punicalagin) – and oral constituents (cells, salivary proteins and mucosal pellicle). So, pectic polysaccharide fractions isolated from grape skins, imidazole soluble polysaccharides (ISP) and carbonate soluble polysaccharides (CSP), as well as a commercial pectin, were tested.Results showed that the polysaccharide's effect depends on the structural features of the molecules involved. CSP fraction and pectin were the most effective, reducing the interactions between both tannins and the oral constituents, mainly in the complete oral model. The highest uronic acid content and the presence of methyl esterified groups could explain their high reduction ability. For tannic acid, the reduction effect increased along with the galloylation degree, while the interaction of β-punicalagin with the oral constituents was practically inhibited at 3.0 mg.mL−1.

Structure and In Vitro Fermentation Characteristics of Polysaccharides Sequentially Extracted from Goji Berry (Lycium barbarum) Leaves.

Herein, the chelating agent-soluble fraction (CA), sodium carbonate-soluble fraction (SC), and sodium hydroxide-soluble fraction (SH) were sequentially extracted from the cell wall of goji berry (Lycium barbarum) leaves. Furthermore, SC was purified with Q-Sepharose fast flow resin to obtain the neutral sugar fraction (SC-I) and acid sugar fraction (SC-II). Physicochemical properties of polysaccharides were characterized by high-performance anion-exchange chromatography with pulsed amperometry detection, size exclusion chromatography-multi-angle laser light scattering, Fourier transform infrared spectroscopy, nuclear magnetic resonance, and atomic force microscopy analysis. Additionally, the impact of polysaccharides on modulating human gut microbiota was investigated by in vitro fermentation. A high amount of galacturonic acid (GalA) in CA showed that it was an aggregation of linear homogalacturonan. SC was the main pectic polysaccharide fraction and rich in neutral sugars. SC-I was the neutral sugar fraction with an extremely high molecular weight (2.055 × 106 Da), while SC-II was the acid sugar fraction with a low molecular weight (1.766 × 105 Da). SH seemed like a mixture of pectin and hemicellulose. All the five polysaccharides significantly (P < 0.05) increased the abundance of Bacteroides, Bifidobacteria, and Lactobacilli. To the best of our knowledge, this is the first report on the structure and fermentation characteristics of goji berry leaf polysaccharides, which is meaningful to provide a structural basis for further bioactivity research.

Structural study of a pectic polysaccharide fraction isolated from “mountain tea” (Sideritis scardica Griseb.)

The present study was conducted to investigate the structural characteristics of an acid-extracted polysaccharide fraction from mountain tea. The monosaccharide composition revealed that uronic acids (72.4 mol%) considerably predominated in the fraction, followed by smaller amounts of galactose (14.5 mol%) and glucose (6.2 mol%). The fraction contained mostly a highly methyl-esterified homogalacturonan (HG) – 71 mol%. The pectin had a high molecular weight population (∼60−100 kDa). Enzymatic fingerprinting was employed with a combination of HG degrading enzymes and LC-HILIC-MS, HPAEC, HPSEC to examine the structure in greater detail. Unsaturated oligomers released indicated the presence of large blocks of highly methyl-esterified GalA residues. Furthermore, the presence of blocks of non-esterified GalA residues and partly methyl-esterified and acetylated GalA residues in HG domain was demonstrated. The research findings provide a basis for further investigations regarding biological activity and commercial exploitation of mountain tea.

The effect of pectic polysaccharides from grape skins on salivary protein – procyanidin interactions

In this study, water and chelator-soluble pectic polysaccharide fractions were obtained from white grape skins, aiming to study their impact on the interaction between low polymerized grape seed procyanidins and salivary proteins. Water and chelator-soluble polysaccharide fractions were composed by uronic acids and neutral sugars, mainly arabinose and galactose, with water polysaccharide fraction showing a higher amount of branched pectic polysaccharides. Both polysaccharide fractions were able to mitigate salivary protein-procyanidin interactions, by a competition mechanism, resulting in a decrease of the amount of precipitated protein. Water polysaccharide fraction was the most effective in inhibiting salivary protein precipitation, especially for acidic proline-rich proteins, due to the higher affinity to interact with procyanidins (KA = 22222 M−1 and KA = 365 M-1 for water and chelator polysaccharides, respectively). The interaction between polysaccharides and procyanidins showed to be mainly governed by hydrophobic effect.

Gastroprotective activity of a pectic polysaccharide fraction obtained from infusion of Sedum dendroideum leaves

BackgroundSedum dendroideum, popularly known in Brazil as balsam, is traditionally used as a wound healing agent, to treat gastritis, and several other health problems. Some studies have shown that plant polysaccharides may have gastroprotective properties. PurposeConsidering the popular use of S. dendroideum and the gastroprotective activity of polysaccharides, the objective of this work was to obtain, to characterize, and to evaluate the gastroprotective activity of a polysaccharide fraction from this plant. MethodsPolysaccharides of S. dendroideum were extracted with water by infusion, fractionated by freeze-thawing process and dialyzed at a 100 kDa cut-off membrane, and characterized by monosaccharide composition and NMR analysis. The gastroprotective activity of the pectic polysaccharide fraction RSBAL was evaluated in the ethanol-induced ulcer model in rats, followed by determination of the mucus and glutathione levels in the gastric tissue. ResultsRSBAL was constituted by a homogalacturonan and a homogalacturonan branched by side chains of arabinans and type II arabinogalactans. It reduced ethanol-induced gastric ulcers in rats, preserving mucus and glutathione levels in the stomach. ConclusionThis study demonstrated that polysaccharides could be related to the pharmacological activity of S. dendroideum.

Purification and Partial Structural Characterization of a Complement Fixating Polysaccharide from Rhizomes of Ligusticum chuanxiong.

Rhizome of Ligusticum chuanxiong is an effective medical plant, which has been extensively applied for centuries in migraine and cardiovascular diseases treatment in China. Polysaccharides from this plant have been shown to have interesting bioactivities, but previous studies have only been performed on the neutral polysaccharides. In this study, LCP-I-I, a pectic polysaccharide fraction, was obtained from the 100 °C water extracts of L. chuangxiong rhizomes and purified by diethylaminethyl (DEAE) sepharose anion exchange chromatography and gel filtration. Monosaccharide analysis and linkage determination in addition to Fourier transform infrared (FT-IR) spectrometer and Nuclear magnetic resonance (NMR) spectrum, indicated that LCP-I-I is a typical pectic polysaccharide, with homo-galacturonan and rhamnogalacturonan type I regions and arabinogalactan type I and type II (AG-I/AG-II) side chains. LCP-I-I exhibited potent complement fixation activity, ICH50 of 26.3 ± 2.2 µg/mL, and thus has potential as a natural immunomodulator.

Physicochemical characterization, antioxidant capacity, total phenolic and proanthocyanidin content of flours prepared from pequi (Caryocar brasilense Camb.) fruit by-products

The potential of pequi by-products as substrates for the production of flours rich in antioxidant dietary fibers was evaluated. Dietary fiber contents ranged from 39.8 to 43.3g/100g with pectic polysaccharide fraction constituted of rhamnogalacturonans and hemicellulose fraction consisted of arabinogalactans, xylans and glucomannans. Total polyphenols, non-extractable proanthocyanidins (NEPA) and carotenoid contents of the flours were determined (respectively, 15.5-17.4g GAE/100g, 215.54-346.84mg/100g and 2116.52-3499.03μg/100g). The antioxidant capacities of pequi by-product flours (986.94-1154.42μM TE/g ABTS; 44.43-48.02g/g DPPH; and 3027.31-3216.27μmol Fe2SO4/g FRAP) were found to be exceptionally higher than those of fruits and fruits by-products reported in the literature. Exocarp removal promoted no significant changes in the technological properties of the flour, except for color. Results showed promising prospects for future exploitation of pequi peel as a potential source of dietary fiber and natural antioxidants.

α-Amylase-assisted extraction of polysaccharides from Panax ginseng

In this paper, α-amylase-assisted extraction was used to isolate the polysaccharide that remained in hot water-extracted ginseng. The yield of the polysaccharide was 9.0%, almost equal to that of the hot water-extracted polysaccharide. Using anion exchange and gel permeation chromatography, the polysaccharide was fractionated into a neutral polysaccharide fraction and six pectic fractions. The neutral fraction accounted for 76% of the polysaccharide and contained both amylopectin and amylose. The pectic polysaccharide fractions were identified to be arabinogalactan, type-I rhamnogalacturonan and homogalacturonan-type pectin by high-performance liquid chromatography, Fourier transform-infrared and nuclear magnetic resonance analysis. Structural and lymphocyte proliferation activity results showed that these polysaccharides were different from those extracted by hot water, indicating that ginseng contains complex polysaccharides with diverse structures, which results in its diverse pharmacological activities. The α-amylase-assisted extraction is a novel method for preparing ginseng polysaccharides and could be applied toward the further study and exploration of ginseng. These findings provide technical and theoretical support for ginseng pharmacology.

Immunomodulating pectins from root bark, stem bark, and leaves of the Malian medicinal tree Terminalia macroptera, structure activity relations

The root bark, stem bark, and leaves of Terminalia macroptera were sequentially extracted with ethanol, 50% ethanol–water, and 50°C water using an accelerated solvent extractor (ASE). Six bioactive purified pectic polysaccharide fractions were obtained from the 50°C crude water extracts after anion exchange chromatography and gel filtration. The root bark, stem bark, and leaves of T. macroptera were all good sources for fractions containing bioactive polysaccharides. The high molecular weight fraction 50WTRBH-I-I, being the most active fraction in the complement fixation test, has a highly ramified rhamnogalacturonan type I (RG-I) region with arabinogalactan type II (AG-II) side chains. The most abundant fractions from each plant part, 50WTRBH-II-I, 50WTSBH-II-I, and 50WTLH-II-I, were chosen for pectinase degradation. The degradation with pectinase revealed that the main features of these fractions are that of pectic polysaccharides, with hairy regions (RG-I regions) and homogalacturonan regions. The activity of the fractions obtained after pectinase degradation and separation by gel filtration showed that the highest molecular weight fractions, 50WTRBH-II-Ia, 50WTSBH-II-Ia, and 50WTLH-II-Ia, had higher complement fixation activity than their respective native fractions. These results suggest that the complement fixation activities of these pectins are expressed mainly by their ramified regions.

Systematic investigations of anthocyanin–metal interactions by Raman spectroscopy

The FT‐Raman spectra of the chloride salts of pelargonidin‐3‐glucoside, cyanidin‐3‐glucoside and delphinidin‐3‐glucoside, their structures at pH 5.0 and their interaction with aluminium and ferric ions are presented for the first time and discussed with regard to their spectroscopic response. Two marker bands at approximately 1510 and 1330/1350 cm−1 and one band at approximately 1330/1350 cm−1 were identified being characteristic for the formation of ferric and aluminium chelates, respectively, of cyanidin‐3‐glucoside and delphinidin‐3‐glucoside. In contrast, pelargonidin‐3‐glucoside, exhibiting one single hydroxyl group in the B‐ring, did not form metal chelates, which could be clearly demonstrated by missing marker bands. The formation of anthocyanin–metal chelates was also verified in model systems containing commercial sugar beet pectin and a pectic polysaccharide fraction isolated thereof, respectively. In addition, the absence of anthocyanin–metal chelates in systems prepared with citrate buffer was confirmed, and the effects of low and high methoxylated citrus pectins on chelate formation were studied. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Bathochromic and stabilising effects of sugar beet pectin and an isolated pectic fraction on anthocyanins exhibiting pyrogallol and catechol moieties

The formation of anthocyanin–metal chelates, exhibiting intense blue colours was monitored over a period up to 10weeks. Evaluating normalised absorption spectra in the range of 580–700nm and their proportion of the total area under the curve (AUC), provided information about the blue colour hue, intensity and stability. Colour stability in model solutions containing commercial sugar beet pectin or an isolated pectic polysaccharide fraction (PPF) therefrom, both being naturally enriched in aluminium and ferric ions, was assessed in a pH range of 3.6–7.0. The pectic structures stabilised anthocyanin–metal chelates, and thus blue colours by efficiently preventing complex precipitation. Highest bathochromic shifts and most intense blue colours were observed in PPF model solutions containing delphinidin-3-glucoside (Dpd-3-glc), exhibiting a pyrogallol moiety in the flavylium B-ring, compared to cyanidin- (Cyd-3-glc) and petunidin-3-glucoside (Pet-3-glc), both carrying a catechol substituted B-ring. Hue and intensity of the blue colour at pH 5.0 were only insignificantly influenced by the buffer system except for citrate and phosphate buffers, which both annihilated anthocyanin–metal chelate formation. The blue colours faded following first order kinetics. Best stabilities as deduced from storage experiments performed at 20±2°C in the dark were observed for Dpd-3-glc. In contrast, Cyd-3-glc displayed shortened half-life values, whereas blue Pet-3-glc chelates decomposed rapidly. These results demonstrate that the solubilisation of anthocyanin–metal chelates by pectic structures is a promising option for developing water soluble natural blue food colourants.

Difference in structure and complement fixing activity of pectic polysaccharides from different plant parts of Echinacea purpurea (L.) Moench.

Water soluble pectic polysaccharide fractions were isolated from different parts of Echinacea purpurea in order to elucidate any structural and biological differences. Water extracts of stems, leaves, flower buds, open flowerheads, post fertile flowers and roots were purified by ion exchange chromatography and by gelfiltration. The polysaccharides consisted of a high amount of galacturonic acid, but also rhamnose, arabinose and galactose with glycosidic linkages compatible with rhamnogalacturonan type I (RG-I), arabinogalactan I (AG-I) and arabinogalactan II (AG-II) structures. Precipitation with Yariv-reagent supports the presence of AG-II. The polysaccharides isolated from the different plant part showed largely the same structure, but with some differences mainly in the arabinan component. The complement fixing activity varied considerable between the plant parts. The structural elucidation indicated that the glycosidic linkages to arabinose are important for the complement fixating activity, and thus a diminished activity after weak hydrolysis of the pectic fractions was observed. Key words: Complement fixing activity, Echinacea, glycosidic linkages, pectic polysaccharides, Yariv-reagent.

Characterisation of sugar beet pectin fractions providing enhanced stability of anthocyanin-based natural blue food colourants

The bathochromic effect resulting from the addition of sugar beet pectin (SBP) to black currant juice, purified anthocyanins (ACN-E) and purified polyphenol extracts comprising both anthocyanins and non-anthocyanin phenolics (PP-E), respectively, were monitored by VIS spectroscopy at varying pH relevant to food formulations (pH 3.6–5.0). Furthermore, a low molecular pectic polysaccharide fraction (PPF) was isolated from SBP using 70% aqueous 2-propanol and further characterised with respect to its chemical composition and mineral content. The marked bathochromic effect was found to be due to the formation of anthocyanin–metal chelate complexes. Only at pH 5.0 SBP entailed a moderate bathochromic shift of 12nm in model solutions containing ACN-E. This effect was enhanced in PPF model solutions resulting in a λmax shift up to 50nm, bringing about an intense blue colour. The bathochromic shift was boosted with increasing pH and upon purification of the anthocyanins. In contrast, after SBP and PPF addition to black currant juice, the bathochromic effect was almost annihilated. Model solutions were stored at 20°C in the dark for 12days, and optimum stability of the blue colour was observed at pH 5.0.

The Antitumor and Immunostimulating Activities of Water Soluble Polysaccharides from Radix Aconiti, Radix Aconiti Lateralis and Radix Aconiti Kusnezoffii

In the present study, the water-soluble polysaccharides of Radix Aconiti, Radix Aconiti Lateralis and Radix Aconiti Kusnezoffii, were extracted and fractionated into four fractions of each material. The FT-IR and chemical analyses indicated the water-soluble polysaccharides of the three materials were all mainly composed of starch, non-starch type alpha-D-glucans and pectic polysaccharides with different molecular weight distributions and monosaccharide composition ratios. The antitumor assay showed that all the non-starch type polysaccharide fractions had good antitumor activities, and the tumor growth inhibition ratios were 37.24-70.42%. Specifically the inhibition ratios of pectic polysaccharides were over 60%. Moreover, the immunological tests using the Cyclophosphamide (Cy) induced immunosuppressive mice, including phagocytosis of macrophage, NK cell activity, concanavalin A (ConA)-induced T-cell proliferation, lipopolysaccharide (LPS)-induced B-cell proliferation, quantitative haemolysis of sheep red blood cells (SRBC) and dinitro-fluorobenzene (DNFB)-induced delayed-type hypersensitivity (DTH) response assays, exhibited that all the non-starch type polysaccharides, especially the pectic polysaccharide fractions, not only had remarkable immunostimulating activities including nonspecific immunity, cellular immunity and humoral immunity, but also could restore the antitumor drug-suppressed immune function. Therefore, the polysaccharides from Aconitum species might be conveniently exploited to be good immune stimulating modifiers and had the potential to apply in the tumor therapy.

Isolation and characterization of pectic polysaccharides from the seeded fruit of oil pumpkin ( Cucurbita pepo L. var. Styriaca)

Seeded fruit of oil pumpkin ( Cucurbita pepo L. var. Styriaca) represents a rich source of pectic polysaccharides. Pectic polysaccharides were isolated by a three-step extraction procedure at various reaction conditions, where 0.01 M ethylendiaminotetraacetic acid was used as extractant in the first step and 1% and 5% NaOH in the second and third steps. A classical extraction procedure (60 min) or and two procedures (U- and UP-experiments) with short applications of ultrasound (5–10 min) were used in the first extraction step. In comparison to the classical extraction, higher or similar yields of low-esterified pectic polysaccharide fractions were obtained from the short ultrasound-assisted extraction, where after sonication the extraction process in the first step was stopped (U-experiments). Prolongation of the extraction time after sonication in the first step to 60 min (UP-experiments) resulted in more than 2% higher yields of polysaccharides from the first and second steps, the last representing non-esterified pectic polysaccharides. The major portion of polysaccharides was obtained in the first and second steps, representing 80–89% of the total isolated polysaccharides. In the third step, pectic polysaccharides containing considerable amounts of hemicelluloses were isolated. All polysaccharide fractions were contaminated to various extents with protein. The sonication treatment had no effect on the total phenolics content (0.6–2.0%). The overall antioxidant activity in the 2,2-diphenyl-1-picrylhydrazyl (DPPH ) assay of fractions from first and second steps of the classical and ultrasound-assisted extractions was very low. In contrast, the pectin/hemicellulose fractions from the third step, particularly of the U-experiment, exhibited considerable “efficient concentrations” (EC 50) ranged from 14 to 21 when compared to that of quercetin (EC 50 = 0.14) used as positive control. EC 50 is defined as the concentration of substrate that causes 50% loss of the DPPH activity. The results suggested that the pumpkin polysaccharide fractions represent dietary fibers with a high content of pectin and/or beneficial antioxidant properties, which might be suitable for functional food applications.

Changes in Pectic Polysaccharides during the Ripening of Cherry Tomato Fruits.

Pectic polysaccharides in cherry tomato fruits (Pepe) have been studied at three stages of ripening (immature-green, mature-green, and mature-red). The alcohol-insoluble solids obtained from the fruits were fractionated into four groups of pectic polysaccharides: water-soluble pectin (WP), hexametaphosphate-soluble pectin (PP), HCl-soluble pectin (HP), and KOH-soluble pectin (KP). The content of total pectic polysaccharides decreased with ripening of the fruits; especially, the main fraction HP at immature-green stage hardly existed at the mature-red stage. Instead, the content of WP increased with maturation. The pectic polysaccharide fractions were analyzed by gel-filtration, and the molecular weight of each fraction decreased with ripening. This phenomenon was accompanied by an increase in the activities of the pectin-hydrolyzing enzymes, polygalacturonase and pectinesterase. These results indicate that the softening of cherry tomato fruits during the ripening may depend on degradation and depolymerization of pectic polysaccharides by the pectin-hydrolyzing enzymes.

B-cell proliferation activity of pectic polysaccharide from a medicinal herb, the roots of Bupleurum falcatum L. and its structural requirement.

Pectic polysaccharide fraction (BR-2) containing pharmacologically active pectic polysaccharide, bupleuran 2IIc, which was prepared from a medicinal herb, the roots of Bupleurum falcatum L., was administered orally to C3H/HeJ mice for 7 consecutive days. Proliferative responses of spleen cells were enhanced in the presence of the purified pectic polysaccharide, bupleuran 2IIc, but another B-cell mitogen, lipopolysaccharide (LPS) did not give a similar effect. In vitro studies using spleen cells showed that bupleuran 2IIc also stimulated lymphocytes, depleted of adherent cells or T cells. Bupleuran 2IIc treatment increased subpopulation of CD25+ and surface immunoglobulin M-positive (sIgM+) lymphocytes. Non-specific immunoglobulin secretion of spleen cells treated with bupleuran 2IIc was increased according to the culture time, and coexistence of interleukin-6 (IL-6) enhanced the secretion more than that of bupleuran 2IIc alone. These results suggest that bupleuran 2IIc proliferates B cells in the absence of macrophages, and the resulting activated B cells are then induced into antibody-forming cells in the presence of IL-6. Among the structural region of bupleuran 2IIc, ramified region (PG-1), which consists of rhamnogalacturonan core rich in neutral sugar chain, showed the potent mitogenic activity suggesting it to be an active site. Mitogenic activity of bupleuran 2IIc was reduced in the presence of antipolysaccharide antibody (antibupleuran 2IIc/PG-1-IgG), which recognizes the ramified region of bupleuran 2IIc as the antigenic epitope. Mitogenic activity of bupleuran 2IIc was also reduced by the addition of beta-d-GlcpA-(1-->6)-beta-d-Galp-(1-->6)-d-Galp or beta-d-GlcpA-(1-->6)-d-Galp, which are a part of the epitopes of antibupleuran 2IIc/PG-1-IgG. These results suggest that the epitopes in bupleuran 2IIc act as active sites of the polysaccharide during mitogenic activity.

Structural Changes in the Cell-Wall Pectic Polysaccharides Accompanied by Softening of Apple (Malus pumila Mill.) Cultivars Fuji and Kinsei

Cell wall material (CWM) prepared from apple cultivars, cv. Fuji with excellent storability and cv. Kinsei with poor storability, before and after storage were fractionated into four pectic polysaccharide fractions (CDTA-1, CDTA-2, Na2CO3-1 and Na2CO3-2), three hemicellulose fractions (KOH-1, KOH-2 and KOH-3) and CWM residue (cellulose rich fraction). Quantitative changes of their fractions from apple cultivars with different storability before and after storage were also compared. In cv. Fuji, the weight of each fraction changed only slighting after storage for 42 day at 20°C, but in cv. Kinsei, the weight of Na2CO3-1 fraction containing pectic polysaccharides decreased most markedly among 8 fractions after storage for 42 days at 20°C. The analysis of monosaccharide composition of Na2CO3-1 fraction showed that the release of arabinose and galactose from the pectic polysaccharide was markedly higher in cv. Kinsei than in cv. Fuji after storage for 42 days at 20°C, suggesting that the reduction of Na2CO3-1 fraction is closely correlated with the release of arabinose and galactose moieties from the pectic polysaccharide of Na2CO3-1 fraction accompanied by softening. This suggests that degradation of bulky arabinogalactan side chain in major pectic substances, rhamnogalcturonan I in Na2CO3-1, may have an important role in the softening process of apples.

Solubilization of pectic polysaccharides from the cell walls of Lemna minor and Apium graveolens

The kinetics of solubilization of pectic polysaccharides from purified cell walls of Lemna minor (duckweed) and Apium graveolens (celery) by ammonium oxalate at 22° was determined. With cell walls of L. minor, 30 ± 1 (average of three experiments, average deviation from the mean) and 34 ± 1% of the total anhydrouronic acid of the cell walls was solubilized in 15 min and 5 hr, respectively. Water at 22° solubilized 1.3 ± 0.2% and 1.3 ± 0.4% of the total anhydrouronic acid in 15 min and 5 hr, respectively. With cell walls of A. graveolens, 19 ± 1% (average of two experiments, average deviation from the mean) and 23 ± 1% of the total anhydrouronic acid of the cell wall was solubilized in 15 min and 3 hr, respectively. Water at 22° solubilized 0.9 ± 0.6 and 0.9 ± 0.1% of the total anhydrouronic acid in 15 min and 3 hr, respectively. When trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid was the extractant, recovery values based on weight for the soluble pectic polysaccharide fractions were incorrect (high). Color formation in the uronic acid test was inhibited by sodium dodecyl sulfate. A rapid, two-step procedure for isolating purified cell walls was developed.

Immunochemical characterization of alkaline-soluble polysaccharide, P-1, from the kernels of Prunus mume Sieb. et Zucc.

Polyclonal antibodies against P-1, a pectic polysaccharide fraction extracted with 0.5 M NaOH from the kernels of Prunus mume and consisted of arabino-galacturonan, and I-3, the partial acid (0.1 M trifluoroacetic acid) hydrolysate of P-1, were prepared in Japanese white rabbits. Competitive ELISA experiments strongly suggested that anti P-1 and anti I-3 antibodies were different but P-1 and I-3 cross-reacted with each other to recognize a partly similar epitope structure. The reactivities of polysaccharide fractions from the raw flesh of P. mume, and the kernels of apricot and peach extracted with either water or sodium hydroxide were examined using both antisera by the indirect competitive ELISA method. The polysaccharide fractions extracted with sodium hydroxide solutions had the reactivities but not those extracted with cold and hot water. These facts suggested that the similar structure of polysaccharides to P-1 was present in the flesh of P. mume and the kernels of apricot and peach. However, neither pectin of apple nor citrus had reactivity with each antiserum. P-1 would be different in chemical structure from a commercially available pectin, a water-soluble polysaccharide from apple and citrus.