An experimental design approach to the chemical characterisation of pectin polysaccharides extracted from Cucumis melo Inodorus

Selenochemical modification of low molecular weight polysaccharides from Grifola frondosa and the mechanism of their inhibitory effects on gastric cancer cells

An important micronutrient involved in immune response and antitumor is selenium. LMW-GFP, a polysaccharide extracted from Grifola frondosa seed bodies, has a relatively weak antitumor effect on BGC-823 and MFC cells in vitro, whereas selenium binding to LMW-GFP can significantly increase the in vitro antitumor activity of LMW-GFP. In this study, Se-LMW-GFP was prepared by the HNO3-Na2SeO3 method, and the structures of LMW-GFP and Se-LMW-GFP were characterized by UV-visible spectroscopy of absorption, FTIR spectroscopy, and electron scanning microscopy, and these structural analyses showed that selenium was successfully complexed to LMW-GFP. The selenium content of Se-LMW-GFP was measured to be 2.08 % ± 0.08 % by ICP-MS. The anti-tumor activity of LMW-GFP before and after selenium modification was compared by cellular experiments, and the findings indicated that the anti-tumor activity of Se-LMW-GFP was considerably improved over that of LMW-GFP, and inhibited the proliferation of BGC-823 cells and MFC cells through a combination of the Fas/FasL-mediated exogenous death receptor pathway as well as the endogenous mitochondrial pathway. Our results suggest that Se-LMW-GFP not only has great potential for natural health food and anti-gastric cancer drug development but is also a good selenium supplement.

Characterization of the surface-active exopolysaccharide produced by Halomonas sp TGOS-10: Understanding its role in the formation of marine oil snow

In this study, we characterize the exopolymer produced by Halomonas sp. strain TGOS-10 -one of the organisms found enriched in sea surface oil slicks during the Deepwater Horizon oil spill. The polymer was produced during the early stationary phase of growth in Zobell's 2216 marine medium amended with glucose. Chemical and proton NMR analysis showed it to be a relatively monodisperse, high-molecular-mass (6,440,000 g/mol) glycoprotein composed largely of protein (46.6% of total dry weight of polymer). The monosaccharide composition of the polymer is typical to that of other marine bacterial exopolymers which are generally rich in hexoses, with the notable exception that it contained mannose (commonly found in yeast) as a major monosaccharide. The polymer was found to act as an oil dispersant based on its ability to effectively emulsify pure and complex oils into stable oil emulsions-a function we suspect to be conferred by the high protein content and high ratio of total hydrophobic nonpolar to polar amino acids (52.7:11.2) of the polymer. The polymer's chemical composition, which is akin to that of other marine exopolymers also having a high protein-to-carbohydrate (P/C) content, and which have been shown to effect the rapid and non-ionic aggregation of marine gels, appears indicative of effecting marine oil snow (MOS) formation. We previously reported the strain capable of utilising aromatic hydrocarbons when supplied as single carbon sources. However, here we did not detect biodegradation of these chemicals within a complex (surrogate Macondo) oil, suggesting that the observed enrichment of this organism during the Deepwater Horizon spill may be explained by factors related to substrate availability and competition within the complex and dynamic microbial communities that were continuously evolving during that spill.

Studies on the Changes of Fermentation Metabolites and the Protective Effect of Fermented Edible Grass on Stress Injury Induced by Acetaminophen in HepG2 Cells

In this study, gas chromatography-mass spectrometry (GC-MS) based untargeted metabolomics was used to describe the changes of metabolites in edible grass with Lactobacillus plantarum (Lp) fermentation durations of 0 and 7 days, and subsequently to investigate the protective effect of fermented edible grass on acetaminophen-induced stress injury in HepG2 cells. Results showed that 53 differential metabolites were identified, including 31 significantly increased and 22 significantly decreased metabolites in fermented edible grass. Fermented edible grass protected HepG2 cells against acetaminophen-induced stress injury, which profited from the reduction in lactate dehydrogenase (LDH) and malondialdehyde (MDA) levels and the enhancement in superoxide dismutase (SOD) activity. Cell metabolomics analysis revealed that a total of 13 intracellular and 20 extracellular differential metabolites were detected. Fermented edible grass could regulate multiple cell metabolic pathways to exhibit protective effects on HepG2 cells. These findings provided theoretical guidance for the formation and regulation of bioactive metabolites in fermented edible grass and preliminarily confirmed the protective effects of fermented edible grass on drug-induced liver damage.

A wide diversity exists in pectin structure from thirteen apple cultivars

To emphasize that differences in pectin structure among cultivars play a crucial role in the texture and quality of fruits and vegetables, the sugar content and methyl-esterification of pectin fractions from 13 apple cultivars was studied. Cell wall polysaccharides were isolated as alcohol-insoluble solids (AIS) and subsequently extracted to yield water-soluble solids (WSS) and chelating-soluble solids (ChSS). All fractions contained significant amounts of galacturonic acid, while sugar compositions varied between cultivars. AIS and WSS pectins showed a degree of methyl-esterification (DM) > 50 %, while ChSS pectins had either a medium (~50 %) or low (<30 %) DM. Homogalacturonan as major structure was studied using enzymatic fingerprinting. Methyl-ester distribution of pectin was described by degrees of blockiness and -hydrolysis. Novel descriptive parameters were obtained by measuring the levels of methyl-esterified oligomers released by endo-PG (DB_PGme) and PL (DB_PLme). Pectin fractions differed in relative amounts of non-, moderately-, and highly methyl-esterified segments. WSS pectins were mostly lacking non-esterified GalA sequences, while ChSS pectins had medium DM and many non-methyl-esterified blocks or a low DM with many intermediate methyl-esterified GalA blocks. These findings will be of help to better understand physicochemical properties of apple and its products.

Comparison of structures and emulsifying properties between water-extracted pectins from Fructus aurantii

The structural characteristics of two water-extracted pectic polysaccharides from Fructus aurantii were investigated, and the impacts of their structures on the emulsifying stability were evaluated. FWP-60 (extracted by cold water and followed 60 % ethanol precipitation) and FHWP-50 (extracted by hot water and followed 50 % ethanol precipitation) were both high methyl-esterified pectins, which were composed of homogalacturonan (HG) and highly branched rhamnogalacturonan I (RG-I) regions. The weight-average molecular weight, methyl-esterification degree (DM) and HG/RG-I ratio of FWP-60 were 1200 kDa, 66.39 % and 4.45, respectively, which were 781 kDa, 79.10 % and 1.95 for FHWP-50. The methylation and NMR analysis of FWP-60 and FHWP-50 demonstrated that the main backbone consisted of different molar ratios of →4)-α-GalpA-(1 → and →4)-α-GalpA-6-O-methyl-(1→, and the side chains contained arabinan and galactan. Moreover, the emulsifying properties of FWP-60 and FHWP-50 were discussed. Compared with FHWP-50, FWP-60 had better emulsion stability. Overall, pectin had a linear HG domain and a small number of RG-I domain with short side chains to facilitate the stabilization of emulsions in Fructus aurantii. A comprehensive knowledge of the structure characteristic and emulsifying property would enable us to provide more information and theoretical guidance for the structure and emulsion preparation of Fructus aurantii pectic polysaccharides.

Characterization of the structural, physicochemical, and functional properties of soluble dietary fibers obtained from the peanut shell using different extraction methods

Objective

To propose a possible solution for a peanut by-product, peanut shell (PS), this study evaluated the effects of different methods, including enzymatic extraction (E-SDF), microwave extraction (M-SDF), and pulsed electric field extraction (PEF-SDF), on the characterization of soluble dietary fibers (SDFs) from PS.

Methods

We determined the physicochemical properties, including water- and oil-holding capacities (WHC and OHC), emulsifying properties, rheological properties, functional properties, including pancreatic lipase activity inhibition (PRAI), glucose and cholesterol adsorption capacities (GAC and CAC), and the structural properties of SDFs.

Results

The results showed that PEF-SDF possessed the highest WHC, OHC, and emulsifying properties. M-SDF and PEF-SDF appeared to have more complex and porous structures, and they showed small molecular weights. Notably, PEF-SDF showed the strongest capacities in CAC, GAC, and PRAI.

Conclusions

The results indicate that PEF-SDF is a potential SDF preparation method for a promising dietary fiber (DF) source, PS.

Structural diversity and physicochemical properties of polysaccharides isolated from pumpkin (Cucurbita moschata) by different methods

Natural polysaccharides were isolated and purified from Cucurbita moschata by hot water extraction and mild acid-base sequential extraction. Chemical and instrumental studies revealed that hot water-extracted and mild acid-extracted polysaccharides with molecular masses of 48 kDa and 85 kDa were both pectic polysaccharides with homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) domains, while mild acid-extracted polysaccharide was more dominated by branched RG-I with higher contents of galactose (10.59 %) and arabinose (8.08 %). Furthermore, mild acid-extracted polysaccharide exhibited better thickening and emulsifying properties, likely due to its larger molecular mass and higher branching degree. Mild base-extracted polysaccharide with a molecular mass of 18 kDa was a glucan-like polysaccharide. It showed the strongest thermostability and gel behavior among these pumpkin polysaccharides, likely attributed to its unique network structure stabilized by substantial intra/intermolecular hydrogen bonds. This study aimed to establish the structure-property relationships between these structurally diverse pumpkin polysaccharides from different extraction methods and provided theoretical foundations for their targeted application in foods.

A review of sugar beet pectin-stabilized emulsion: extraction, structure, interfacial self-assembly and emulsion stability

In recent years, sugar beet pectin as a natural emulsifier has shown great potential in food and pharmaceutical fields. However, the emulsification performance depends on the molecular structure of sugar beet pectin, and the molecular structure is closely related to the extraction method. This review summarizes the extraction methods of pectin, structure characterization methods and the current research status of sugar beet pectin-stabilized emulsions. The structural characteristics of sugar beet pectin (such as degree of methylation, degree of acetylation, degree of blockiness, molecular weight, ferulic acid content, protein content, neutral sugar side chains, etc.) are of great significance to the emulsifying activity and stability of sugar beet pectin. Compared with traditional hot acid extraction method, ultrasonic-assisted extraction, microwave-assisted extraction, subcritical water-assisted extraction, induced electric field-assisted extraction and enzyme-assisted extraction can improve the yield of sugar beet pectin. At the same time, compared with harsh extraction conditions (too high temperature, too strong acidity, too long extraction time, etc.), mild extraction conditions can better preserve these emulsifying groups in sugar beet pectin molecules, which are beneficial to improve the emulsifying properties of sugar beet pectin. In addition, the interfacial self-assembly behavior of sugar beet pectin induced by the molecular structure is crucial to the long-term stability of the emulsion. This review provides a direction for extracting or modifying sugar beet pectin with specific structure and function, which is instructive for finding alternatives to gum arabic.

The effect of biopolymer-water interaction on relaxation phenomena in blackcurrant pectin solutions

Pectin is commonly used food additive. Depends on the source of the acquisition, its properties may vary significantly, therefore pectin obtained from different sources may be used for various purposes. Little information can be found about the properties of blackcurrant pectin. Therefore, the aim of this study was to investigate blackcurrant pectin properties, with particular emphasis on biopolymer behaviour in aqueous solutions. Applied water extraction resulted in a water-soluble fraction of pectin with M_w = 115.75 kg·mol^-1. Aqueous solutions of obtained polysaccharides was tested with various methods (membrane osmometry, DLS, NMR, viscosity tests) that allowed for a comprehensive description of biopolymer-biopolymer and biopolymer-water interactions in both, dilute and semidilute regime. Blackcurrant pectin exhibits behaviour characteristic for polyelectrolytes. The analysis of the obtained results shows that, despite its low molecular weight, obtained pectin has a highly branched structure, which influences strong intermolecular interactions in solutions.

Comparative study on physicochemical characteristics, α-glucosidase inhibitory effect, and hypoglycemic activity of pectins from normal and Huanglongbing-infected navel orange peels

This study aimed at comparing the physicochemical characteristics, α-glucosidase inhibitory effect, and hypoglycemic activity of pectins (N-NOP and H-NOP) from peels of normal and Huanglongbing (HLB)-infected Navel oranges. Results indicated the pectins were high methoxy pectins mainly composed of homogalacturonan and rhamnogalacturonan-I. The pectins exhibited similar functional groups, surface morphology, and particle size, and had no triple-helical conformation in solution. They exerted fat and glucose absorption capacities and were mixed-type noncompetitive α-glucosidase inhibitors with IC₅₀ values of 1.182 and 2.524 mg/ml, respectively. Both N-NOP and H-NOP showed hypoglycemic activity in alloxan-induced diabetic mice. Administration of them could promote the synthesis of hepatic glycogen and/or serum insulin to lower blood glucose levels and enhance antioxidant status to alleviate oxidative stress injury in diabetic mice. Moreover, N-NOP had higher yield, molecular weight, ζ-potential, oil holding capacity, α-glucosidase inhibitory effect and in vivo hypoglycemic activity, whereas H-NOP possessed higher uronic acid, degree of esterification, thermal stability, water holding capacity, swelling capacity, and fat absorption capacity. It could be concluded that some similarities and differences existed between N-NOP and H-NOP in physicochemical characteristics, functional properties, α-glucosidase inhibitory effects, and hypoglycemic activity. This study provides references for the basic research and application of pectins from peels of normal and HLB-infected Navel oranges. PRACTICAL APPLICATIONS: Pectin has been widely used in the food and pharmaceutical industries for several decades due to its health benefit, gelling, thickening, and emulsification performances. Diabetes mellitus is a worldwide concern in recent years. Pectins (N-NOP and H-NOP) from peels of normal and Huanglongbing (HLB)-infected Navel oranges possessed in vitro and in vivo hypoglycemic activities, indicating they were potential anti-antidiabetic substitutes of chemical drugs. Moreover, comparative understanding on the physicochemical characteristic, α-glucosidase inhibitory effect and hypoglycemic activity of pectins from peels of normal and Huanglongbing-infected Navel oranges was conducive to the recycling and utilization of Navel orange peels. Recently, the biological activity of pectin from peels of normal Navel oranges has been rarely reported, and the information on pectin from peels of Huanglongbing-infected Navel orange is rare. This study provides references for the basic research and application of pectins from peels of normal and HLB-infected Navel oranges.

Microstructural and Texturizing Properties of Partially Pectin-Depleted Cell Wall Material: The Role of Botanical Origin and High-Pressure Homogenization

In the current study, the texturizing properties of partially pectin-depleted cell wall material (CWM) of apple, carrot, onion and pumpkin, and the potential of functionalization by high-pressure homogenization (HPH) were addressed. This partially pectin-depleted CWM was obtained as the unextractable fraction after acid pectin extraction (AcUF) on the alcohol-insoluble residue. Chemical analysis was performed to gain insight into the polysaccharide composition of the AcUF. The microstructural and functional properties of the AcUF in suspension were studied before HPH and after HPH at 20 and 80 MPa. Before HPH, even after the pectin extraction, the particles showed a cell-like morphology and occurred separately in the apple, onion and pumpkin AcUF and in a clustered manner in the carrot AcUF. The extent of disruption by the HPH treatments at 20 and 80 MPa was dependent on the botanical origin. Only for the onion and pumpkin AcUF, the water binding capacity was increased by HPH. Before HPH, the texturizing potential of the AcUFs was greatly varying between the different matrices. Whereas HPH improved the texturizing potential of the pumpkin AcUF, no effect and even a decrease was observed for the onion AcUF and the apple and carrot AcUF, respectively.

Modified Rhamnogalacturonan-Rich Apple Pectin-Derived Structures: The Relation between Their Structural Characteristics and Emulsifying and Emulsion-Stabilizing Properties

In the context of the increasing interest in natural food ingredients, the emulsifying and emulsion-stabilizing properties of three rhamnogalacturonan-rich apple pectin-derived samples were assessed by evaluating a range of physicochemical properties. An apple pectin (AP74) was structurally modified by a β-eliminative reaction to obtain a RG-I-rich pectin sample (AP-RG). Subsequent acid hydrolysis of AP-RG led to the generation of pectin material with partially removed side chains (in particular arabinose depleted) (AP-RG-hydrolyzed), thus exhibiting differences in rhamnose, arabinose, and galactose in comparison to AP-RG. All samples exhibited surface activity to some extent, especially under acidic conditions (pH 2.5). Furthermore, the viscosity of the samples was assessed in relation to their emulsion-stabilizing properties. In a stability study, it was observed that the non-degraded AP74 sample at pH 2.5 exhibited the best performance among all the apple pectin-derived samples evaluated. This emulsion presented relatively small oil droplets upon emulsion production and was less prone to creaming than the emulsions stabilized by the (lower molecular weight) RG-I-rich materials. The AP-RG and AP-RG-hydrolyzed samples presented a slightly better emulsion stability at pH 6.0 than at pH 2.5. Yet, neither pectin sample was considered having good emulsifying and emulsion-stabilizing properties, indicated by the presence of coalesced and flocculated oil droplets.

Influence of cations, pH and dispersed phases on pectin emulsification properties

The cooperativity of six cations (Ca²⁺, Mg²⁺, Zn²⁺, Al³⁺, Cr³⁺ and Fe³⁺), three pectins (sugar beet, high and low methyl esterified), three dispersed phases (medium chain triglycerides (MCT), orange oil and hexadecane), time (30 days) and pH (2.0 and 6.0) has been investigated in the formation and stability against coarsening of oil-in-water emulsions. Cations generally influenced emulsion stability in the following order (most stable) Ca²⁺ ​> ​Mg²⁺ ​> ​Al³⁺ ​> ​Cr³⁺ ​> ​Zn²⁺ ​> ​Fe³⁺ (least stable). This order largely coincided with that of the strength of pectin-cation interactions showing that the higher the affinity of cation for pectin the less stable the emulsion. More stable emulsions were formed with sugar beet pectin, which was also unresponsive to the presence of cations, followed by high- and then low-methyl esterified samples. At pH 2.0 all pectins showed their best emulsification performance whereas shifting pH to 6.0 severely impaired emulsification capacity and longer term stability against droplet growth. Smaller droplets were created with hexadecane under all conditions studied followed by MCT and orange oil in agreement with their aqueous solubilities. The present results advance our understanding of the stabilisation of emulsions using pectin and allow us to tailor their functionality for applications in food, pharmaceutical and biomedical industries.

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Cations influence stability in the order: Ca²⁺ ​> ​Mg²⁺ ​> ​Al³⁺ ​> ​Cr³⁺ ​> ​Zn²⁺ ​> ​Fe³⁺.

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Pectins showed best emulsification performance at pH 2.0

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Pectins showed poor emulsification performance at pH 6.0

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Pectin stability order: sugar beet ​> ​high methoxy ​> ​low methoxy pectin.

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Oil stability order at pH 2.0: hexadecane ​< ​medium chain triglycerides ​< ​orange oil.

The Structure and Composition of Extracted Pectin and Residual Cell Wall Material from Processing Tomato: The Role of a Stepwise Approach versus High-Pressure Homogenization-Facilitated Acid Extraction

In literature, different pectin extraction methods exist. In this study, two approaches starting from the alcohol-insoluble residue (AIR) of processing tomato are performed in a parallel way to facilitate the comparison of pectin yield and the compositional and structural properties of the extracted pectin and residual cell wall material obtained. On the one hand, pectin is extracted stepwise using hot water, chelating agents and low-alkaline conditions targeting fractionation of the pectin population. On the other hand, an industrially relevant single-step nitric acid pectin extraction (pH 1.6) is performed. In addition to these conventional solvent pectin extractions, the role of high-pressure homogenization (HPH) as a physically disruptive treatment to facilitate further pectin extraction from the partially pectin-depleted fraction obtained after acid extraction is addressed. The impact of HPH on the pectin cell wall polysaccharide interactions was shown as almost two thirds of the residual pectin were extractable during the subsequent extractions. For both extraction approaches, pectin obtained further in the sequence was characterized by a higher molecular mass and a higher amount of rhamnogalacturonan I domains. The estimated hemicellulose and cellulose content increased from 56 mol% for the AIR to almost 90 mol% for the final unextractable fractions of both methods.

Modelling the Extraction of Pectin towards the Valorisation of Watermelon Rind Waste

Watermelon is the second largest fruit crop worldwide, with great potential to valorise its rind waste. An experimental design was used to model how extraction parameters (temperature, pH, and time) impact on the efficiency of the process, purity, esterification degree, monosaccharide composition and molar mass of watermelon rind pectin (WRP), with an insight on changes in their structural properties (linearity, branching degree and extraction severity). The models for all responses were accurately fitted (R2 > 90%, lack of fit p ≥ 0.05) and experimentally validated. At optimum yield conditions, WRP yield (13.4%), purity (540 µg/g galacturonic acid) and molar mass (106.1 kDa) were comparable to traditional pectin sources but showed a higher branching degree with longer galactan side chains and a higher protein interaction. Harsher conditions (pH 1) generated purer homogalacturonan fractions with average molar masses (80 kDa) at the expense of yield, while mild extraction conditions (pH ≥ 2) produced highly branched entangled pectin structures. This study underlines novel compositional features in WRP and the possibility of producing novel customized pectin ingredients with a wider potential application scope depending on the targeted structure.

The Effect of Different Extraction Conditions on the Physical Properties, Conformation and Branching of Pectins Extracted from Cucumis melo Inodorus

The extraction of pectin involves the physico-chemical hydrolysis and solubilisation of pectic polymers from plant tissues under the influence of several processing parameters. In this study, an experimental design approach was used to examine the effects of extraction pH, time and temperature on the pectins extracted from Cucumis melo Inodorus. Knowledge of physical properties (intrinsic viscosity and molar mass), dilute solution conformation (persistence length and mass per unit length), together with chemical composition, was then used to propose a new method, which can estimate the length and number of branches on the pectin RG-I region. The results show that physical properties, conformation and the length and number of branches are sensitive to extraction conditions. The fitting of regression equations relating length and number of branches on the pectin RG-I region to extraction conditions can, therefore, lead to tailor-made pectins with specific properties for specific applications.

Pectin recovery and characterization from lemon juice waste streams

BACKGROUND

Pectin characteristics from different parts of lemon fruit (Citrus limon L.) were studied as a basis for assessing their suitability for functional applications. Pectin was extracted from lemon albedo, lemon core parts and membranes, and lemon extract using an aqueous extraction protocol. The composition and structural properties of the isolated pectins were examined by means of complementary analytical methods to assess their molecular characteristics for potential industrial applications.

RESULTS

The isolation protocol yielded pectins that were predominantly composed of galacturonic acid, with differences in the degree of methylation and neutral sugars content, and with low protein content, indicating high-purity materials. The same extraction protocol resulted in differences in yield and purity between the three different parts of lemon fruit, and in structural variations in the pectin backbone, as evidenced by differences in sugar composition and molecular weight. Solutions of the isolated lemon pectins exhibited pseudoplastic behavior. Macromolecular characterization showed that the lemon extract pectin had the highest molecular weight and hydrodynamic volume, followed by lemon core and lemon albedo pectin.

CONCLUSION

The work demonstrates that pectins with distinct structural properties may be extracted from different parts of lemon wastes and used for different technological purposes. © 2019 Society of Chemical Industry.

Isolation and Characterization of Pectic Polysaccharide Fraction from In Vitro Suspension Culture of Fumaria officinalis L

In the current study, an acidic polysaccharide from the in vitro suspension culture of Fumaria officinalis L. was obtained by extraction with 0.8% (w/v) aqueous ammonium oxalate. The polysaccharide fraction mainly consisted of galacturonic acid (41.0%), followed by galactose (7.3%) and arabinose (5.6%). This suggests the presence of arabinogalactan side chains in the rhamnogalacturonan-I segment of the studied pectin, which was mainly built up by homogalacturonan segments. The pectin was evaluated as low-methyl-esterified (45.0%) with degree of acetylation 3.4%. The polymer fraction was consisted of different molecular weight populations in the range of 6–600 kDa. The high amount of 4-L-hydroxyproline (11.7% of total protein) and the specific positive reaction to Yariv’s phenylglycoside reagent indicated the presence of an arabinogalactan protein in the cell walls. The functional properties of the polysaccharide fraction were evaluated, as it possessed better water-holding capacity than oil-holding capacity. The studied pectin demonstrated significant foaming ability and promising emulsifying properties in a concentration 1%. Therefore, the isolated polysaccharide fraction could be successfully used as emulsifier and foaming agent in food products and pharmaceutical supplements.

Tilia tomentosa pectins exhibit dual mode of action on phagocytes as β-glucuronic acid monomers are abundant in their rhamnogalacturonans I

Silver linden flowers contain different pectins (PSI-PSIII) with immunomodulating properties. PSI is a low-esterified pectic polysaccharide with predominant homogalacturonan region, followed by rhamnogalacturonan I (RGI) with arabinogalactan II and RGII (traces) domains. PSII and PSIII are unusual glucuronidated RGI polymers. PSIII is a unique high molecular weight RGI, having almost completely O-3 glucuronidated GalA units with >30% O-3 acetylation at the Rha units. Linden pectins induced reactive oxygen species (ROS) and NO generation from non-stimulated whole blood phagocytes and macrophages, resp., but suppressed OZP-(opsonized zymosan particles)-activated ROS generation, LPS-induced iNOS expression and NO production. This dual mode of action suggests their anti-inflammatory activity, which is known for silver linden extracts. PSI expressed the highest complement fixation and macrophage-stimulating activities and was active on intestinal Peyer's patch cells. PSIII was active on non-stimulated neutrophils, as it induced ß₂-integrin expression, revealing that acetylated and highly glucuronidated RGI exhibits immunomodulating properties via phagocytes.

Pectin Penta-Oligogalacturonide Suppresses Intestinal Bile Acids Absorption and Downregulates the FXR-FGF15 Axis in High-Cholesterol Fed Mice

Haw pectin penta-oligogalacturonide (HPPS), purified from the hydrolysates of haw pectin, has important role in decreasing hepatic cholesterol accumulation and promoting bile acids (BA) excretion in the feces of mice fed a high-cholesterol diet (HCD). However, the mechanism is not clear. This study aims to investigate the effects of HPPS on BA reabsorption in ileum and biosynthesis in liver of mice. Results showed that HPPS increased fecal BA output by approximately 110%, but decreased ileal BA and the total BA pool size by approximately 47 and 36%, respectively, compared to HCD. Studies of molecular mechanism revealed that HPPS significantly decreased the mRNA and protein levels of farnesoid X receptor (FXR) in the small intestine of mice and inactivated the fibroblast growth factor 15 (FXR-FGF15) axis, which increased the mRNA and protein levels of CYP7A1 by approximately 204 and 104%, respectively, compared to HCD. Interestingly, the mRNA and protein levels of apical sodium-dependent bile acid transporter (ASBT) in the small intestine were approximately 128 and 73% higher in HPPS-fed mice than those in HCD-fed mice, respectively. However, no significant difference was detected for ASBT expression between HCD group and BA sequestrant cholestyramine group. These findings indicate that HPPS can suppress intestinal BA reabsorption and promoting hepatic BA biosynthesis. We speculated that HPPS could be ASBT competitive inhibitor rather than BA sequestrant in inhibiting BA reabsorption in ileum and improving cholesterol metabolism.

Pectin from muskmelon (Cucumis melo var. reticulatus) peels: extraction optimization and physicochemical properties

Pectin derived from plant waste sources is currently focused as an economical and eco-friendly approach. Optimization of pectin extraction from muskmelon peel by response surface methodology (RSM) was investigated in this study. Box-Behnken Design (BBD) was used to identify the optimal level of the extraction variables such as time, pH and temperature. A second-order model equation for pectin extraction was obtained from multiple regression analysis of experimental data with the correlation coefficient (R ²) value of 0.92. ANOVA results showed that linear effect of temperature and combined effect of pH with temperature were found significant for pectin extraction from muskmelon peel. Validation results had good agreement with the predicted results. Pectin extracted from muskmelon peel was classed as high methoxy pectin with the equivalent weight of 384.5 g/mol. Non-newtonian pseudoplastic flow behaviour was observed for muskmelon pectin from the viscosity studies.

The effect of different extraction techniques on property and bioactivity of polysaccharides from Dioscorea hemsleyi

The rhizoma of Dioscorea hemsleyi (DH) has been used as a treatment of diabetes in China for hundreds of years. Polysaccharides in DH were extracted by using ultrasonic-assisted extraction (UAE), cold water extraction (CWE), warm water extraction (WWE) and hot water extraction (HWE), separately. Then the different characterizations of four DH polysaccharide (DHP) samples were analyzed by high-performance liquid chromatography (HPLC), high-performance Gel permeation chromatography (HGPC), ultraviolet-visible spectroscopy(UV), fourier transform-infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Their activities in vitro of DHP were compared. Experimental results showed that HWE had the highest yield and large molecular weight. CWE had the highest uronic acid yield and little molecular weight, and its DPPH, AGI and AAI activity were the best. The molecular weight of UAE was small, and its RP and FRAP activity were the best. Four DHP samples had differences in the surface topography, while they all had the typical IR spectra characteristic of polysaccharides. According the correlation analysis, it showed that the more uronic acid and the lower molecular weight was, the higher the antioxidant activity was. The high content of monosaccharide composition of Xyl, Ara, GlcA and GalA, and little molecular weight have good effect on antidiabetic activity.

Emerging concepts in the nutraceutical and functional properties of pectin-A Review

Pectin is a structural heteropolysaccharide found ubiquitously in terrestrial plants. It finds diverse food applications such as that of a gelling agent, stabilizer, and fat replacer. In the pharmaceutical arena, pectin exhibits a number of functions, from decreasing blood fat to combating various types of cancers. This review shows the shift of pectin from its conventional roles to its progressive applications. Insights into the advances in the production of pectin, the role it plays as a nutraceutical, possible prebiotic potential and a delivery vehicle for probiotics, and food applications are highlighted. Bioactive and functional properties of pectin are discussed and how the structural built up defines them, is emphasized. As a biopolymer, the applications of pectin in active packaging are also mentioned.

Advances on Bioactive Polysaccharides from Medicinal Plants

In recent decades, the polysaccharides from the medicinal plants have attracted a lot of attention due to their significant bioactivities, such as anti-tumor activity, antioxidant activity, anticoagulant activity, antidiabetic activity, radioprotection effect, anti-viral activity, hypolipidemic and immunomodulatory activities, which make them suitable for medicinal applications. Previous studies have also shown that medicinal plant polysaccharides are non-toxic and show no side effects. Based on these encouraging observations, most researches have been focusing on the isolation and identification of polysaccharides, as well as their bioactivities. A large number of bioactive polysaccharides with different structural features and biological effects from medicinal plants have been purified and characterized. This review provides a comprehensive summary of the most recent developments in physiochemical, structural features and biological activities of bioactive polysaccharides from a number of important medicinal plants, such as polysaccharides from Astragalus membranaceus, Dendrobium plants, Bupleurum, Cactus fruits, Acanthopanax senticosus, Angelica sinensis (Oliv.) Diels, Aloe barbadensis Miller, and Dimocarpus longan Lour. Moreover, the paper has also been focused on the applications of bioactive polysaccharides for medicinal applications. Recent studies have provided evidence that polysaccharides from medicinal plants can play a vital role in bioactivities. The contents and data will serve as a useful reference material for further investigation, production, and application of these polysaccharides in functional foods and therapeutic agents.

Natural Pectin Polysaccharides as Edible Coatings

The most fashionable trends in food packaging research are targeted towards improvements in food quality and safety by increasing the use of environmentally-friendly materials, ideally those able to be obtained from bio-based resources and presenting biodegradable characteristics. Edible films represent a key area of development in new multifunctional materials by their character and properties to effectively protect food with no waste production. The use of edible films should be considered as a clean and elegant solution to problems related with waste disposal in packaging materials. In particular, pectin has been reported as one of the main raw materials to obtain edible films by its natural abundance, low cost and renewable character. The latest innovations in food packaging by the use of pectin-based edible films are reviewed in this paper, with special focus on the use of pectin as base material for edible coatings. The structure, properties related to the intended use in food packaging and main applications of pectins are herein reported.