Effect of Hogweed Pectin on Rheological, Mechanical, and Sensory Properties of Apple Pectin Hydrogel.

This study aims to develop hydrogels from apple pectin (AP) and hogweed pectin (HP) in multiple ratios (4:0; 3:1; 2:2; 1:3; and 0:4) using ionotropic gelling with calcium gluconate. Rheological and textural analyses, electromyography, a sensory analysis, and the digestibility of the hydrogels were determined. Increasing the HP content in the mixed hydrogel increased its strength. The Young's modulus and tangent after flow point values were higher for mixed hydrogels than for pure AP and HP hydrogels, suggesting a synergistic effect. The HP hydrogel increased the chewing duration, number of chews, and masticatory muscle activity. Pectin hydrogels received the same likeness scores and differed only in regard to perceived hardness and brittleness. The galacturonic acid was found predominantly in the incubation medium after the digestion of the pure AP hydrogel in simulated intestinal (SIF) and colonic (SCF) fluids. Galacturonic acid was slightly released from HP-containing hydrogels during chewing and treatment with simulated gastric fluid (SGF) and SIF, as well as in significant amounts during SCF treatment. Thus, new food hydrogels with new rheological, textural, and sensory properties can be obtained from a mixture of two low-methyl-esterified pectins (LMPs) with different structures.

Enrichment of Agar Gel with Antioxidant Pectin from Fireweed: Mechanical and Rheological Properties, Simulated Digestibility, and Oral Processing.

The aims of the study were to evaluate the influence of pectin isolated from fireweed (FP) on the mechanical and rheological properties of agar (A) gel, to investigate the release of phenolic compounds (PCs) and pectin from A-FP gels at simulated digestion in vitro, and to evaluate the oral processing and sensory properties of A-FP gels. The hardness of A-FP gels decreased gradually with the increase in the concentration of FP added (0.1, 0.4, and 1.6%). The hardness of A-FP1.6 gel was 41% lower than A gel. Rheological tests found A gel was a strong physical gel (storage modulus (G') >>loss modulus (G″)), and the addition of FP up to 1.6% did not significantly change its G'. The G″ value decreased in A-FP gels compared to A gel. The release of galacturonic acid (GalA) was 3.4 ± 0.5, 0.5 ± 0.2, 2.4 ± 1.0, and 2.2 ± 0.7 mg/mL after digestion of A-FP1.6 gel in the oral in vivo phase (OP) and subsequent incubation in simulated gastric (SGF), intestinal (SIF), and colonic (SCF) fluids in vitro. The incubation medium after OP, SGF, and SIF digestion of A-FP1.6 contained 24−64 µg GAE/mL of PCs, while SCF contained 144 µg GAE/mL, supposing a predominant release of antioxidant activity from the gel in the colon. Chewing to readiness for swallowing A-FP gel required less time and fewer chews with less activity of the masseter and temporalis muscles. A-FP1.6 gel had a lower likeness score for taste and consistency and a similar score for appearance and aroma when compared with A gel. Thus, A-FP gels were weakened compared to A gel and required less time and muscle activity for oral processing. A-FP gel had antioxidant activity due to the PCs associated with pectin, while A gel had no antioxidant activity.

Swelling, Protein Adsorption, and Biocompatibility In Vitro of Gel Beads Prepared from Pectin of Hogweed Heracleum sosnówskyi Manden in Comparison with Gel Beads from Apple Pectin.

The study aims to develop gel beads with improved functional properties and biocompatibility from hogweed (HS) pectin. HS4 and AP4 gel beads were prepared from the HS pectin and apple pectin (AP) using gelling with calcium ions. HS4 and AP4 gel beads swelled in PBS in dependence on pH. The swelling degree of HS4 and AP4 gel beads was 191 and 136%, respectively, in PBS at pH 7.4. The hardness of HS4 and AP4 gel beads reduced 8.2 and 60 times, respectively, compared with the initial value after 24 h incubation. Both pectin gel beads swelled less in Hanks' solution than in PBS and swelled less in Hanks' solution containing peritoneal macrophages than in cell-free Hanks' solution. Serum protein adsorption by HS4 and AP4 gel beads was 118 ± 44 and 196 ± 68 µg/cm2 after 24 h of incubation. Both pectin gel beads demonstrated low rates of hemolysis and complement activation. However, HS4 gel beads inhibited the LPS-stimulated secretion of TNF-α and the expression of TLR4 and NF-κB by macrophages, whereas AP4 gel beads stimulated the inflammatory response of macrophages. HS4 gel beads adsorbed 1.3 times more LPS and adhered to 1.6 times more macrophages than AP4 gel beads. Thus, HS pectin gel has advantages over AP gel concerning swelling behavior, protein adsorption, and biocompatibility.

Characterization and Biocompatibility Properties In Vitro of Gel Beads Based on the Pectin and κ-Carrageenan.

This study aimed to investigate the influence of kappa (κ)-carrageenan on the initial stages of the foreign body response against pectin gel. Pectin-carrageenan (P-Car) gel beads were prepared from the apple pectin and κ-carrageenan using gelling with calcium ions. The inclusion of 0.5% κ-carrageenan (Car0.5) in the 1.5 (P1.5) and 2% pectin (P2) gel formulations decreased the gel strength by 2.5 times. Car0.5 was found to increase the swelling of P2 gel beads in the cell culture medium. P2 gel beads adsorbed 30-42 mg/g of bovine serum albumin (BSA) depending on pH. P2-Car0.2, P2-Car0.5, and P1.5-Car0.5 beads reduced BSA adsorption by 3.1, 5.2, and 4.0 times compared to P2 beads, respectively, at pH 7. The P1.5-Car0.5 beads activated complement and induced the haemolysis less than gel beads of pure pectin. Moreover, P1.5-Car0.5 gel beads allowed less adhesion of mouse peritoneal macrophages, TNF-α production, and NF-κB activation than the pure pectin gel beads. There were no differences in TLR4 and ICAM-1 levels in macrophages treated with P and P-Car gel beads. P2-Car0.5 hydrogel demonstrated lower adhesion to serous membrane than P2 hydrogel. Thus, the data obtained indicate that the inclusion of κ-carrageenan in the apple pectin gel improves its biocompatibility.

A secret of salivary secretions: Multimodal effect of saliva in sensory perception of food.

Saliva plays multifunctional roles in oral cavity. Even though its importance for the maintenance of oral health has long been established, the role of saliva in food perception has attracted increasing attention in recent years. We encourage researchers to discover the peculiarity of this biological fluid and aim to combine the data concerning all aspects of the saliva influence on the sensory perception of food. This review presents saliva as a unique material, which modulates food perception due to constant presence of saliva in the mouth and thanks to its composition. Therefore, we highlight the salivary components that contribute to these effects. Moreover, this review is an attempt to structure the effects of saliva on perception of different food categories, where the mechanisms of salivary impact in perception of liquid, semi-solid, and solid foods are revealed. Finally, we emphasize that the large inter-individual variability in salivary composition and secretion appear to contribute to the fact that everyone experiences food in their own way. Therefore, the design of the sensory studies should consider the properties of volunteers' saliva and also carefully monitor the experimental conditions that affect salivary composition and flow rate.

Pectin-glycerol gel beads: Preparation, characterization and swelling behaviour.

Low methyl-esterified pectin (AU701) was found to form gel beads with glycerol. Wet AU701-glycerol gel beads exhibited similar diameter and hardness compared to the AU701-Ca gel beads, prepared by ionotropic gelation with Ca2+ and used for comparison. The morphology of dry pectin gel beads determined by scanning electron microscopy revealed that the beads exhibited rough and grooved surface. The AU701-glycerol gel beads absorbed more grams of water than AU701-Ca gel beads (12.2 g vs 3.9 g per 1 g of the beads). Rheological properties and hardness of the AU701-glycerol gel beads improved with the increase of the pectin/glycerol ratio. Swelling behavior of the AU701-glycerol gel beads was determined after sequential incubation in simulated gastric (SGF) and intestinal (SIF) fluids. The AU701-glycerol gel beads swelled in SGF to a greater extent and revealed higher stability in SIF than the gel beads cross-linked by Ca2+.

Swelling behavior and satiating effect of the gel microparticles obtained from callus cultures pectins.

Gel microparticles were prepared from pectins of campion (SVCgel) and duckweed (LMCgel) callus cultures, as well as from commercial apple pectin (APgel) by emulsion dehydration techniques with successive ionotropic gelation. The morphology and swelling behavior of the microparticles were determined after successive incubation in simulated gastric (SGF), intestinal (SIF), and colonic (SCF) fluids. Both SVCgel and LMCgel microparticles were found to swell in SGF and SIF gradually, and at oral administration decreased food intake by laboratory mice during the first 5 h of free-feeding. The SVCgel microparticles demonstrated the higher stability in SCF within 24 h than LMCgel ones. Only the SVCgel microparticles were shown to decrease food intake by 24% during the 21 h of free-feeding and decreased body weight of mice by 4% during 24 h after oral administration. The APgel microparticles lost their shape in SIF, then fully disintegrated after 0.5 h of incubation in SCF, and failed to affect food intake or mice body weight. The data obtained indicated that sustainability and swelling of the gel microparticles from the SVC pectin in the colonic fluid may provide the stronger satiating effect compared to that of the LMCgel microparticles.

Pectin gelling in acidic gastric condition increases rheological properties of gastric digesta and reduces glycaemic response in mice.

The rheological characteristics and transit time of gastric digesta and the postprandial glycaemic response in mice orally administered with water (control) or pectin solutions supplemented (AP-Ca) or not supplemented (AP) with CaCO3 were elucidated. AP and AP-Ca increased viscosity, storage and loss moduluses (G' and G'') of mice gastric digesta. The gelling capacity of AP-Ca in acidic gastric conditions appeared to provide a greater enhancement of gastric digesta viscosity compared with AP. The postprandial blood glucose concentration was lower in mice orally administered with AP or AP-Ca compared with control mice. The transit time of gastric digesta and the blood glucose concentration were affected in mice orally administered with AP during the early postprandial period. The effect of AP-Ca on the gastric digesta rheology and transit time was stronger than that of AP. Both of the pectin solutions failed to reduce food intake in mice.

Structure characterization of the mannofucogalactan isolated from fruit bodies of Quinine conk Fomitopsis officinalis.

The mannofucogalactan as a major component of water extract was obtained from fruit bodies of Fomitopsis officinalis by extraction with boiling water followed by deproteination, decoloration, and purification using anion-exchange chromatography and size exclusion chromatography. Its structure was characterized using the data of monosaccharide composition, methylation analysis, one- and two-dimensional NMR spectroscopy. The studied polysaccharide was a branched mannofucogalactan with a backbone composed of partially 3-O-methylated 1,6-O-linked α-D-galactopyranosyl residues. Almost every second residue in the backbone was substituted at O-2 by 3-O-α-D-mannopyranosyl-α-L-fucopyranosyl and ß-D-galactopyranosyl residues. The non-reducing terminal α-L-fucopyranosyl units, which were identified by GC-MS analyses, appeared to be the part of mannofucogalactan side chains also.

Pectic polysaccharides of the fresh plum Prunus domestica L. isolated with a simulated gastric fluid and their anti-inflammatory and antioxidant activities.

A pectic polysaccharide, designated as PD, was extracted from fresh plums (Prunus domestica L.) with a simulated gastric fluid. Galacturonan, which was partially substituted with methyl and O-acetyl ester groups, and rhamnogalacturonan were the main constituents of the linear regions of the sugar chains of PD. The ramified region contained mainly 1,4-linked ß-d-galactopyranose residues and, to a lesser extent, 1,5-linked α-l-arabinofuranose residues. The separation of PD, by DEAE-cellulose column chromatography, yielded two pectic fractions: PD-1 and PD-2, eluted with 0.1 and 0.2 M NaCl, respectively. Enzymatic digestion of PD with 1,4-α-d-polygalacturonase yielded the fraction PD-E. The parent pectin PD and the PD-1 fraction were found to diminish the adhesion of peritoneal leukocytes at the concentrations of 0.05-1.0mg/ml. However, the PD-E fraction failed to have an effect on cell adhesion at the concentrations of 0.05-0.1mg/ml. PD, PD-1 and PD-E were found to inhibit the production of superoxide anion radicals by reducing xanthine oxidase activity by 38%, 97% and 47%, respectively. Therefore, the PD-1 fraction appeared to be an active fragment of pectic macromolecule isolated from fresh plum with a simulated gastric fluid.

Immunomodulatory activity of polysaccharides isolated from Clerodendrum splendens: beneficial effects in experimental autoimmune encephalomyelitis.

BACKGROUND: Extracts of leaves from Clerodendrum have been used for centuries to treat a variety of medicinal problems in tropical Africa. However, little is known about the high-molecular weight active components conferring therapeutic properties to these extracts. METHODS: Polysaccharides from the leaves of Clerodendrum splendens were extracted and fractionated by ion exchange and size-exclusion chromatography. Molecular weight determination, sugar analysis, degree of methyl esterification, and other chemical characterization of the fractions were performed. Immunomodulatory activity of the fractions was evaluated by determining their ability to induce monocyte/macrophage nitric oxide (NO), cytokine production, and mitogen-activated protein kinase (MAPK) phosphorylation. Experimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6 mice, and severity of EAE was monitored in mice treated with intraperitoneal (i.p.) injections of the most active polysaccharide fraction. Lymph nodes (LN) and spleen were harvested, and levels of cytokines in supernatants from LN cells and splenocytes challenged with myelin oligodendrocyte glycoprotein peptide were determined. RESULTS: Fractions containing type II arabinogalactan had potent immunomodulatory activity. Specifically, the high-molecular weight sub-fraction CSP-AU1 (average of 38.5 kDa) induced NO and cytokine [interleukin (IL)-1α, -1ß, -6, -10, tumor necrosis factor (TNF; designated previously as TNF-α), and granulocyte macrophage-colony stimulating factor (GM-CSF)] production by human peripheral blood mononuclear cells (PBMCs) and monocyte/macrophages. CSP-AU1-induced secretion of TNF was prevented by Toll-like receptor 4 (TLR4) antagonist LPS-RS, indicating a role for TLR4 signaling. Treatment with CSP-AU1 also induced phosphorylation of a number of MAPKs in human PBMC and activated AP-1/NF-κB. In vivo treatment of mice with CSP-AU1 and CSP-NU1 resulted in increased serum IL-6, IL-10, TNF, monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein (MIP)-1α/CCL3, and MIP-1ß/CCL4. CSP-AU1 treatment of mice with EAE (50 mg/kg, i.p., daily, 13 days) resulted in significantly reduced disease severity in this experimental model of multiple sclerosis. Levels of IL-13, TNF, interferon (IFN)-γ, IL-17, and GM-CSF were also significantly decreased, whereas transforming growth factor (TGF)-ß was increased in LN cells from CSP-AU1-treated EAE mice. CONCLUSIONS: Polysaccharide CSP-AU1 is a potent natural innate immunomodulator with a broad spectrum of agonist activity in vitro and immunosupressive properties after chronic administration in vivo.

Structural characterisation of the polysaccharides from endemic Mongolian desert plants and their effect on the intestinal absorption of ovalbumin.

Using successive extractions with water and 0.7% aqueous ammonium oxalate, pectic polysaccharides were isolated from the following plants growing in the arid climate of Mongolia (Gobi): saxaul Haloxylon ammodendron Maxim., rhubarb Rheum nanum Sievers, Nitraria sibirica Pall., Peganum harmala L. and almond Amygdalus mongolica Maxim. The data obtained exhibited the primary synthesis of the cell wall pectic polysaccharides but not the middle lamellae water-soluble pectins in plants growing in the dry climatic zone. Both α-(1→4)-D-galacturonan and α-(1→4)-D-galacturonan, which was substituted with methyl groups, were found to be backbone of pectins. The L-arabinofuranose residues were identified as the main components of ramified regions. The pectins from almond differed from other pectins due to a high arabinose content. The data from NMR spectroscopy and methylation analyses demonstrated that pectic polysaccharides from almond included terminal, (1→5)-, (1→3)-linked and 3,5-substituted L-arabinofuranose residues and a small terminal D-galactopyranose and 2,5- and 2,3,5-substituted L-arabinofuranose residue content. The pectic polysaccharides were found to decrease the absorption of ovalbumin (OVA) in the blood from the gut lumen. The serum OVA level was lower in mice fed with OVA mixed with the pectins compared with the control group, which was administered OVA alone.

Structure of pectic polysaccharides isolated from onion Allium cepa L. using a simulated gastric medium and their effect on intestinal absorption.

The polysaccharide fraction extracted with simulated gastric juice from onion bulbs contained a mixture of galactan with short-length sugar chains, pectic polysaccharides and evident content of proteinaceous material. Galacturonan and rhamnogalacturonan were the main constituents of the linear regions of the sugar chains of the pectic polysaccharides. The ramified regions included rhamnogalacturonan-I. NMR data revealed that the side chains of the ramified region contained mainly 1,4-linked ß-D-galactopyranose residues and lesser content of 1,3-linked ß-D-galactopyranose and 1,5-linked α-L-arabinofuranose residues. Furthermore, the proteinaceous material was determined to be partly linked to the sugar chains. The polysaccharide fraction was found to decrease absorption of ovalbumin (OVA) to the blood from the gut lumen. The serum OVA level was threefold lower in mice fed with OVA mixed with the onion pectins compared with the control group, which was administered OVA alone. Protein removal failed to abolish the inhibitory effect of the onion polysaccharides, confirming that the polysaccharide chains are the active component of onion gastric juice extract.

Abrogation of the oral tolerance to ovalbumin in mice by citrus pectin.

OBJECTIVE: We studied the effects of dietary pectins (citrus pectin [CP] and apple pectin) on oral tolerance in mice. METHODS: Pectins (1 mg/d) were administered orally for 2 wk. Tolerance was induced with 20 mg of ovalbumin (OVA). Levels of serum antibodies (immunoglobulin [Ig] G, IgG1, IgG2a, IgE) and delayed type hypersensitivity response determined in footpad tests were measured after subcutaneous injection of OVA with complete Freund's adjuvant. Concentrations of immunoreactive OVA in blood were measured by enzyme-linked immunosorbent assay after feeding the animals 20 mg of OVA. Adhesion and cytokine production (tumor necrosis factor-alpha, interferon-gamma) were measured in peritoneal macrophages. RESULTS: Oral administration of CP was found to prevent the induction of immune hyporesponsiveness induced by OVA feeding. Animals fed OVA and CP were found to produce similar titers of antigen-specific serum IgG and levels of delayed type hypersensitivity response as those animals not fed OVA. CP increased levels of serum IgG1 and IgE. CP was found to enhance the penetration of immunogenic OVA into the serum. CP (1 mg/d) administered orally for 1 wk was also observed to enhance the adhesion and production of cytokines (tumor necrosis factor-alpha, interferon-gamma) in peritoneal macrophages. CONCLUSION: CP administered orally was shown to inhibit oral tolerance. Enhancement of protein antigen penetration to the blood and activation of macrophages were found to precede the inhibitory effect and appeared to mediate it.

Adjuvant effect of lemnan, pectic polysaccharide of callus culture of Lemna minor L. at oral administration.

A pectic polysaccharide, lemnan LMC, was extracted from the callus of duckweed Lemna minor L. and was tested for adjuvant properties at oral administration with protein antigen. Mice were orally immunized thrice with weekly interval with free hen's egg lysozyme or lysozyme with LMC. Lemnan LMC was shown to increase delayed type hypersensitivity and serum antilysozyme IgG responses. LMC was established to increase levels of both serum IgG1 and IgG2a subclasses. The concentration of malondialdehyde and myeloperoxidase activity were found to be higher in the tissue samples obtained from small intestine of mice immunized with mixture of lysozyme/LMC than those immunized with lysozyme only. Thus, lemnan appeared to be useful as the adjuvant for oral immunization.

Characterisation of the oral adjuvant effect of lemnan, a pectic polysaccharide of Lemna minor L.

Lemnan LM, apiogalacturonanic pectin of duckweed Lemna minor L. was tested for adjuvant properties following oral administration with protein antigen. Male Swiss mice were orally immunized thrice with weekly intervals with free OVA or OVA with lemnan (LM). Lemnan LM was shown to increase delayed type hypersensitivity (DTH) and serum anti OVA IgG responses. LM was established to increase levels of both serum IgG1 and IgG2a subclasses, intestinal IgA and failed to elevate levels of serum IgE. Lemnan was found to increase the adhesion of macrophages and to enhance the generation of oxygen radicals by macrophages in response to phorbol 12-myristate 13-acetate. Serum OVA levels were four-fold higher in mice immunized with the mixture of OVA and LM in comparison with those in mice immunized with OVA only. Thus, substantial systemic and local mucosal immune responses were attained by oral immunization with the mixture of OVA and lemnan. Lemnan appeared to elicit adjuvant activity via induction of both Th1- and Th2-type responses. The immunopotentiating effect of lemnan may result from enhanced antigen ingestion and stimulation of macrophage activity.