Isolation and characterization of acetylated LM-pectins extracted from okra pods

Hawthorn (Crataegus pinnatifida) berries ripeness induced pectin diversity: A comparative study in physicochemical properties, structure, function and fresh-keeping potential

The effect of hawthorn berries ripeness on the physicochemical, structural and functional properties of hawthorn pectin (HP) and its potential in sweet cherry preservation were investigated. With the advanced ripeness of hawthorn berries, the galacturonic acid (GalA) content decreased from 59.70 mol% to 52.16 mol%, the molecular weight (Mw) reduced from 368.6 kDa to 284.3 kDa, the microstructure exhibited variable appearance from thick lamella towards porous cross-linked fragment, emulsifying activity and emulsions stability, antioxidant activities, α-amylase and pancreatic lipid inhibitory capacities significantly increased. The heated emulsion stored for 30 d presented higher creaming index and more ordered oil droplets compared to the unheated emulsion. With the extended berries ripeness, the firmness of HP gels remarkably decreased from 225.69 g to 73.39 g, while the springiness increased from 0.78 to 1.16, HP exhibited a superior inhibitory effect in water loss, browning, softening, and bacterial infection in sweet cherries preservation.

Structural and rheological properties of diluted alkali soluble pectin from apple and carrot

Pectin, a complex polysaccharide found in plant cell walls, plays a crucial role in various industries due to its functional properties. The diluted alkali-soluble pectin (DASP) fractions that result from the stepwise extraction of apples and carrots were studied to evaluate their structural and rheological properties. Homogalacturonan and rhamnogalacturonan I, in different proportions, were the main pectin domains that composed DASP from both materials. Atomic force microscopy revealed that the molecules of apple DASP were longer and more branched. A persistence length greater than 40 nm indicated that the pectin molecules deposited on mica behaved as stiff molecules. The weight-averaged molar mass was similar for both samples. Intrinsic viscosity values of 194.91 mL·g-1 and 186.79 mL·g-1 were obtained for apple and carrot DASP, respectively. Rheological measurements showed greater structural strength for apple-extracted pectin, whereas carrot pectin was characterized by a higher linear viscoelasticity limit. This comparison showed that the pectin fractions extracted by diluted alkali are structurally different and have different rheological properties depending on their botanical origin. The acquired insights can enhance the customized use of pectin residue and support further investigations in industries relying on pectin applications.

Characterization, antioxidant activity and in vitro digestion of hawthorn pectin prepared by gradient ethanol precipitation

Four modified hawthorn pectin fractions (MHPs), named MHP-30, MHP-50, MHP-70 and MHP-90, were obtained by ultrasonic-assisted pectin methyl esterase modification and gradient ethanol precipitation. The results indicated that all four MHPs were composed of galacturonic acid, galactose, xylose, arabinose, glucose and mannose in different proportions. With the increase of the ethanol concentration, the molecular weight, esterification degree and galacturonic acid content of MHPs all decreased, whereas the arabinose content and branching degree increased. The structural characterization from XRD, SEM, and FT-IR showed that four MHPs exhibited amorphous structure, similar functional groups, diverse surface morphologies. Besides, in vitro antioxidant assays confirmed that MHP-70 and MHP-90 exhibited stronger total antioxidant activities than MHP-30 and MHP-50. The results of simulated saliva-gastrointestinal digestion showed that the molecular weight of MHP-70 and MHP-90 remained stable, yielded small amounts of reducing sugars, and were resistant to digestion in the human upper digestive tract. Overall, MHP-70 and MHP-90 shown great potential as novel natural antioxidants, which are expected to be good carbon sources for the utilization of intestinal microorganisms.

Molecular docking and in vivo protective effects of okra (Abelmoschus esculentus) against metabolic dysfunction in high-fat, high-sodium diet-fed rats

Okra pods (Abelmoschus esculentus L. Moench) have been used as a functional vegetable as they contain polysaccharides, flavonoids, and other bioactive molecules that protect the body from several chronic diseases. The purpose of this study was to look at the involvement of okra constituents (mucilage and flesh) in the prevention of metabolic dysfunctions induced in a rat model by a high-fat, high-salt (HF/NaCl) diet. Okra mucilage was extracted using an ultrasonic method, freeze-dried, characterized using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM), and tested for swelling ratio and radical scavenging activity. Okra flesh (skin and seeds) was separated from pods; characterized using SEM; and tested for dietary fiber content, phenolic profile, and radical scavenging activity. The significance of okra bioactive compounds in inhibiting human salivary amylase, glutamine : fructose-6-phosphate amidotransferase (GFAT), tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP) was investigated using molecular docking. Rats were fed an HF/NaCl diet and orally treated daily with freeze-dried okra mucilage or flesh (100 mg per kg body weight) for 8 weeks. Glucose, insulin, inflammatory indicators (CRP, TNF-α, and interleukin 6), oxidative markers (red blood cell lipid peroxidation, glutathione peroxidase, nitric oxide, and superoxide dismutase), lipid profile, estradiol, feces lipids as well as femur and urine calcium were measured. The molecular docking findings showed the interaction of quercetin and chlorogenic acid, which are the most abundant phenolic compounds in okra pods, with the studied proteins, which gives an indication of the mechanism of okra's anti-diabetic, anti-oxidant, and anti-inflammatory effects. Okra mucilage and flesh significantly reduced glucose, insulin, cholesterol, lipid peroxidation, CRP, TNF-α, IL-6, and urine calcium levels while significantly increasing feces lipid and femur calcium levels. The findings suggested that okra mucilage and flesh seem to be promising candidates for protection against metabolic dysfunction.

Effect of hydrochloric acid and citric acid with ultrasound processing on characteristics of superfine-ground pectic polysaccharides from okra (Abelmoschus esculentus L.) peel

The structural properties and biological activities of okra pectic polysaccharides (OPs) were impacted by various extraction methods. Based on commonly grinding (40, 100 meshes) and superfine grinding okra powders, two extraction solvents (hydrochloric acid, HA; citric acid, CA) were used firstly. Next, the extraction yield, physical and chemical properties, molecular structure and functional properties of OPs were analyzed by non-ultrasonic treatment and ultrasound-assisted superfine grinding method. The outcomes demonstrated that the extraction yield of OPs rose as the particle size of the powder decreased. HA-OPs had higher molecular weight (Mw), apparent viscosity and emulsification ability than CA-OPs. CA-OPs had higher esterification degree (DE), solubility and total sugar content, and higher amounts of rhamnogalacturonan-I (RG-I) segments. Compared with OPs without ultrasound-assisted extraction, ultrasound-assisted superfine grinding extraction exhibited higher sugar content, antioxidant capacity, emulsification ability, lower Mw, DE and apparent viscosity. Finally, the correlation between structure and function of OPs was further quantified. The antioxidant capacity was positively correlated with RG-I content, and negatively correlated with DE and Mw. The emulsification ability was mainly positively correlated with the GlcA of OPs. This study provides a theoretical basis for the development of OPs foods with clear structure-function relationship, which would be instructive for the application of OPs in food and cosmetics.

Fructooligosaccharides from Cynoglossum tubiflorus: Effect of the molecular size on their antidiabetic activity in high-fat diet and alloxan induced diabetic rats

The use of acetylation followed by silica gel column purification allowed the isolation of eight fructooligosaccharides (FOS) from the ethanol extract of Cynoglossum tubiflorus roots. Each FOS was identified by analyzing its FT-IR, HRMS/MS and NMR data, including 1H, 13C and 2D NMR HH COSY, HMBC and NOESY. In diabetic rats treated with a series of FOS from Glc-(Fru)3 to Glc-(Fru)7, a significant inhibition of intestinal α-amylase was observed. This activity increases proportionally with the FOS molecular size. It was found that they delay the absorption of total cholesterol (TC), ldl-cholesterol (LDL-C) and increase HDL-cholesterol (HDL-C) in a molecular size-dependent manner. This inhibitory effect on the activity of the digestive enzyme causes a significant (p < 0.05) reduction in the level of glucose in the blood as an anti-diabetic action. The ethanolic extract (E.E) exerts a significant effect against α-amylase as well as antihyperglycemic and antihyperlipidemic actions, while its acetylation suppresses these effects. Therefore, this study demonstrates for the first time that pure FOS act as an efficient agent in preventing hyperglycemia and hyperlipidemia and that this action evolves in the same manner with their molecular size.

Synthesis of Pectin and Eggshell Biowaste-Mediated Nano-hydroxyapatite (nHAp), Their Physicochemical Characterizations, and Use as Antibacterial Material

The current study reports the synthesis of sustainable nano-hydroxyapatite (nHAp) using a wet chemical precipitation approach. The materials used in the green synthesis of nHAp were obtained from environmental biowastes such as HAp from eggshells and pectin from banana peels. The physicochemical characterization of obtained nHAp was carried out using different techniques. For instance, X-ray diffractometer (XRD) and FTIR spectroscopy were used to study the crystallinity and synthesis of nHAp respectively. In addition, the morphology and elemental composition of nHAP were studied using FESEM equipped with EDX. HRTEM showed the internal structure of nHAP and calculated its grain size which was 64 nm. Furthermore, the prepared nHAp was explored for its antibacterial and antibiofilm activity which has received less attention previously. The obtained results showed the potential of pectin-bound nHAp as an antibacterial agent for various biomedical and healthcare applications.

Spontaneous gelation behaviors and mechanism of Ficus awkeotsang Makino pectin

Ficus awkeotsang Makino (jelly fig) can produce edible gels by rubbing its seeds in water at room temperature in which pectin is considered as the main gelling component. However, the spontaneous gelation mechanism of Ficus awkeotsang Makino (jelly fig) pectin (JFSP) is still unclear. This study aimed to reveal the structure, physicochemical properties, and spontaneous gelation behaviors and mechanism of JFSP. JFSP was first obtained by water extraction and alcohol precipitation method, with a pectin yield of 13.25 ± 0.42 % (w/w), weight-average molar mass (Mw) of 111.26 kDa, and methoxylation degree (DM) of 26.8 %. Analysis of monosaccharide compositions showed that JFSP was composed of 87.8 % galactose acid, indicating a high percentage of galacturonic acid blocks. Measurement on the gelling capacity suggested that JFSP gels can be easily formed by simply dispersing the pectin in water at room temperature without adding any co-solutes or metal ions. Gelation force analysis indicated that hydrogen bonding, hydrophobic interactions, and electrostatic interactions were the main factors contributing to gel formation. At 1.0 % (w/v) of pectin concentration, JFSP gels exhibited relatively high gel hardness (72.75 ± 1.15 g) and good thermal and freeze-thawing stability. Overall, these findings highlight the potential application of JFSP as a promising commercial pectin resource.

A critical review of RG-I pectin: sources, extraction methods, structure, and applications

In recent years, RG-I pectin isolated by low-temperature alkaline extraction methods has attracted the attention of a large number of researchers due to its huge health benefits. However, studies on other applications of RG-I pectin are still lacking. In this study, we summarized the sources (e.g. potato pulp, sugar beet pulp, okra, apple pomace, citrus peel, pumpkin, grapefruit, ginseng, etc.), extraction methods, fine structure and applications of RG-I pectin in physiological activities (e.g. anti-cancer, anti-inflammatory, anti-obesity, anti-oxidation, immune regulation, prebiotics, etc.), emulsions, gels, etc. These neutral sugar side chains not only endow RG-I pectin with various physiological activities but the entanglement and cross-linking of these side chains also endow RG-I pectin with excellent emulsifying and gelling properties. We believe that this review can not only provide a comprehensive reading for new workers interested in RG-I pectin, but also provide a valuable reference for future research directions of RG-I pectin.

Pectin-like polysaccharide extracted from leaves Crataeva tapia promotes antioxidant, immunomodulatory and emulsifiers applied in therapeutic formulations

The objective of this work was to isolate a polysaccharide similar to pectin from Crataeva tapia leaves, not yet reported in the literature, and to evaluate its antioxidant, cytotoxic and immunomodulatory profile. Pectin was extracted from the leaves in three stages, organic solvent followed by acidified water and ethanol precipitation. With the pectin obtained, the physicochemical characterization of the molecule was carried out using high-performance liquid chromatography, Fourier-transform infrared spectroscopy, nuclear magnetic resonance (13C and 1H) and different thermal and elemental analysis. Furthermore, the antioxidant activities were evaluated in vitro, and using human peripheral blood mononuclear cell culture, cytotoxicity and immunostimulatory actions were investigated. Physical and chemical analyses showed characteristic signs of pectin. Antioxidant activity tests showed that pectin had moderate to low antioxidant activity. Furthermore, pectin did not affect the viability of erythrocytes and PBMC and induced an immunostimulatory state when it promoted the production of cytokines IL-6, IL-10 and TNF-α and increased the activation of CD8 + T lymphocytes. This study showed that pectin from Crataeva tapia is not cytotoxic and promoted a pro-inflammatory profile in peripheral blood mononuclear cell with application as an immunostimulating and emulsifying compound.

Naturally and chemically acetylated polysaccharides: Structural characteristics, synthesis, activities, and applications in the delivery system: A review

Acetylated polysaccharides refer to polysaccharides containing acetyl groups on sugar units. In the past, the acetylation modification of wall polysaccharides has been a hot research topic for scientists. However, in recent years, many studies have reported that acetylation-modified plant, animal, and microbial polysaccharide show great potential in delivery systems. From the latest perspective, this review systematically presents the different sources of naturally acetylated polysaccharides, the regularity of their modification, the chemical preparation of acetylation modifications, the biological activities and functions of acetylated polysaccharides, and the application in the delivery system. In nature, acetylated polysaccharides are extensively distributed in plants, microorganism, and animals. The level of acetylation modification, the distribution of chains, and the locations of acetylation modification sites differ between species. An increasing number of acetylated polysaccharides were prepared in the aqueous medium, which is safe, environment friendly, and low-cost. In addition to being necessary for plant growth and development, acetylated polysaccharides have immunomodulatory, antioxidant, and anticancer properties. The above-mentioned multiple sources, multifunctional and multi-active acetylated polysaccharides, make them an increasingly important part of delivery systems. We conclude by discussing the future directions for research and development and the potential uses for acetylated polysaccharides.

Effects of various degrees of esterification on antioxidant and immunostimulatory activities of okra pectic-polysaccharides

Pectic-polysaccharides are considered as one of the most abundant bioactive components in okra, which possess various promising health-promoting effects. However, the knowledge regarding the structure-bioactivity relationship of okra pectic-polysaccharides (OPP) is still limited. In this study, effects of various degrees of esterification (DEs) on in vitro antioxidant and immunostimulatory activities of OPP were analyzed. Results displayed that OPP with high (42.13%), middle (25.88%), and low (4.77%) DE values were successfully prepared by mild alkaline de-esterification, and their primary chemical structures (compositional monosaccharide and glycosidic linkage) and molecular characteristics (molecular weight distribution, particle size, and rheological property) were overall stable. Additionally, results showed that the notable decrease of DE value did not significantly affect antioxidant activities [2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) and nitric oxide (NO) radical scavenging abilities as well as ferric reducing antioxidant power (FRAP)] of OPP, suggesting that the DE was not closely related to its antioxidant activity. In fact, the slight decrease of antioxidant activity of OPP after the alkaline de-esterification might be attributed to the slight decrease of uronic acid content. Nevertheless, the immunostimulatory effect of OPP was closely related to its DE, and a suitable degree of acetylation was beneficial to its in vitro immunostimulatory effect. Besides, the complete de-acetylation resulted in a remarkable reduction of immune response. The findings are beneficial to better understanding the effect of DE value on antioxidant and immunomodulatory activities of OPP, which also provide theoretical foundations for developing OPP as functional foods or health products.

Enzymatic Hydrolysis Modifies Emulsifying Properties of Okra Pectin

Okra pectins (OKPs) with diverse structures obtained by different extraction protocols have been used to study the relationship between their molecular structure and emulsifying properties. A targeted modification of molecular structure offers a more rigorous method for investigating the emulsifying properties of pectins. In this study, three glycoside hydrolases, polygalacturonase (PG), galactanase (GL), and arabinanase (AR), and their combinations, were used to modify the backbone and side-chains of OKP, and the relationships between the pectin structure and emulsion characteristics were examined by multivariate analysis. Enzymatic treatment significantly changed the molecular structure of OKP, as indicated by monosaccharide composition, molecular weight, and structure analysis. GL- and AR- treatments reduced side-chains, while PG-treatment increased side-chain compositions in pectin structure. We compared the performance of hydrolyzed pectins in stabilizing emulsions containing 50% v/v oil-phase and 0.25% w/v pectin. While the emulsions were stabilized by PG (93.3% stability), the emulsion stability was reduced in GL (62.5%), PG+GL+AR (37.0%), and GL+AR (34.0%) after 15-day storage. Furthermore, microscopic observation of the droplets revealed that emulsion destabilization was caused by flocculation and coalescence. Principal component analysis confirmed that neutral sugar side-chains are key for long-term emulsion stabilization and that their structure explains the emulsifying properties of OKP. Our data provide structure-function information applicable to the tailored extraction of OKP with good emulsification performance, which can be used as a natural emulsifier.

Solid Lipid Nanoparticles of Lepidium Sativum L Seed Extract: Formulation, Optimization and In vitro Cytotoxicity Studies

The current study focused on important bioactive compounds in plants that make them pharmacologically valuable. Therefore, this study was aimed to develop Lepidium sativum (L. sativum) seed extract loaded solid lipid nanoparticles and explore its cytotoxic effect on human liver cancer cells (HepG2 cells). The ethanolic extract of L. sativam used to develop L. sativum seed extract loaded solid lipid nanoparticles (SLNs) was analyzed by gas chromatography-mass spectrometry, thin-layer chromatography (TLC) and high-performance thin-layer chromatography (HPTLC) for phytochemical profiling. The L. sativum seed extract loaded SLNs were efficaciously prepared by the nanoprecipitation method and screened on the basis of physicochemical properties. The L. sativum seed extract loaded SLN-2 was characterized using various parameters like particle size (237.1±0.104), % entrapment efficiency (80±1.15), zeta potential (42.1±0.102) and % drug release (45% at the end 8 hours and release the entire amount in 12 h). The SLN-2 formulation was optimized based on the recipient factor, and SLN-2 was used to further evaluate the in vitro cytotoxicity of HepG2 cells in a dose-dependent manner by 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) assay. The IC50 value of SLN2 was 52.37 ug/ml and sub IC50 26.1 ug/ml at 24 h and 48 h, respectively. Thus, we concluded that L. sativum extract loaded SLN-2 could act as an alternative therapy, possibly controlling therapeutic action by making a substantial reduction in side effects.

Physicochemical and Functional Properties of Okra Leaf Polysaccharides Extracted at Different pHs

Different extraction pH values obtain polysaccharides with tailored structures and novel functionalities. This study investigated the influence of different extraction pH values (4.2, 6.8, and 9.2) on the physicochemical compositions and structural and functional properties of okra leaf polysaccharides (OLPs). The extraction yield (2.74–7.34%), molecular weights (68.5–85.4 kDa), total sugar contents (64.87–95.68%), degree of acetylation (18.28–22.88%), and methylation (8.97–15.20%) of OLPs varied significantly (p < 0.05). The monosaccharide composition reflected OLPs as pectic polysaccharides, with varied compositions of galacturonic acid, galactose, rhamnose, and arabinose. However, the differences in their sugar molar ratios, such as their side-chain and backbone chain compositions, greatly affected their functional properties. Additionally, notable differences due to extraction pH were observed in physical properties, thermal stability, and crystallinity. However, FTIR and NMR spectra revealed that extraction pH had negligible effects on the primary structure of OLPs. All OLPs showed non-Newtonian fluid behavior in the aqueous system with different apparent viscosities correlating with their molecular weights. Furthermore, the OLPs fractions stabilized oil-in-water emulsions differently and had distinct radical scavenging activities related to their compositions. This study provides a basis for selecting appropriate extraction pH to prepare OLPs with specific characteristics and applications in food-related disciplines.

Structure and functionality of Rhamnogalacturonan I in the cell wall and in solution: A review

Rhamnogalacturonan I (RG-I) belongs to the pectin family and is found in many plant cell wall types at different growth stages. It plays a significant role in cell wall and plant biomechanics and shows a gelling ability in solution. However, it has a significantly more complicated structure than smooth homogalacturonan (HG) and its variability due to plant source and physiological state contributes to the fact that RG-I's structure and function is still not so well known. Since functionality is a product of structure, we present a comprehensive review concerning the chemical structure and conformation of RG-I, its functions in plants and properties in solutions.

Effect of Cactus (Opuntia ficus-indica) and Acacia (Acacia seyal) Gums on the Pasting, Thermal, Textural, and Rheological Properties of Corn, Sweet Potato, and Turkish Bean Starches

This study was planned to explore the locally available natural sources of gum hydrocolloids as a natural modifier of different starch properties. Corn (CS), sweet potato (SPS), and Turkish bean (TBS) starches were mixed with locally extracted native or acetylated cactus (CG) and acacia (AG) gums at 2 and 5% replacement levels. The binary mixtures (starch–gums) were prepared in water, freeze dried, ground to powder, and stored airtight. A rapid viscoanalyzer (RVA), differential scanning calorimeter (DSC), texture analyzer, and dynamic rheometer were used to explore their pasting, thermal, textural, and rheological properties. The presence of acetylated AG or CG increased the final viscosity (FV) in all three starches when compared to starch pastes containing native gums. Plain SPS dispersion had a higher pasting temperature (PT) than CS and TBS. The addition of AG or CG increased the PT of CS, SPS, and TBS. The thermograms revealed the overall enthalpy change of the starch and gum blends: TBS > SPS > CS. The peak temperature (T_p) of starches increased with increasing gum concentration from 2 to 5% for both AG and CG native and modified gums. When compared to the control gels, the addition of 2% CG, either native or modified, reduced the syneresis of starch gels. However, further addition (5% CG) increased the gels’ syneresis. Furthermore, the syneresis for the first cycle on the fourth day was higher than the second cycle on the eighth day for all starches. The addition of native and acetylated CG reduced the hardness of starch gels at all concentrations tested. All of the starch dispersions had higher G′ than G″ values, indicating that they were more elastic and less viscous with or without the gums. The apparent viscosity of all starch gels decreased as shear was increased, with profiles indicating time-dependent thixotropic behavior. All of the starch gels, with or without gums, showed a non-Newtonian shear thinning trend in the shear stress vs. shear rate graphs. The addition of acetylated CG gum to CS resulted in a higher activation energy (Ea) than the native counterparts and the control. More specifically, starch gels with a higher gum concentration (5%) provided greater Ea than their native counterparts.

High-quality pectin from cantaloupe waste: eco-friendly extraction process, optimization, characterization and bioactivity measurements

BACKGROUND

The rind from cantaloupe is an agricultural waste of cantaloupe industrial processing. The current study tried to (i) evaluate the potential use of cantaloupe rind as a pectin source, (ii) optimize the factors of microwave-assisted extraction process using Box-Behnken design, and (iii) characterize the isolated pectin using various physicochemical, structural, functional and bioactivity properties.

RESULTS

Four variables of the extraction process were successfully optimized at a microwave power of 700 W, irradiation time of 112 s, pH value of 1.50 and liquid to solid (LS) value of 30 mL g^-1 , with a yield of 181.4 g kg^-1 . The analysis indicated a high-methylated galacturonic acid-rich (703.4 g kg^-1 ) sample with an average molecular weight of 390.475 kDa. Also, the isolated pectin showed considerable functionality and antioxidant ability. The main functional groups, structural characteristics and crystallinity of samples were comparatively studied using Fourier transform infrared, nuclear magnetic resonance and X-ray diffraction spectroscopies.

CONCLUSION

In comparison to commercial citrus pectin, isolated pectin showed a significantly higher value for most of the functional analysis such as oil holding capacity, emulsifying capacity, emulsion stability, DPPH^• and ABTS^•+ scavenging activity, and reducing power assay. In other analyses the isolated sample was close to the commercial one, indicating that cantaloupe rinds should be considered as a suitable additional resource for pectin production. © 2021 Society of Chemical Industry.

Utilization of Pectin from Okra as Binding Agent in Immediate Release Tablets

Polymeric materials from plants continue to be of interest to pharmaceutical scientists as potential binders in immediate release tablets due to availability, sustainability, and constant supply to feed local pharmaceutical industries. Paracetamol tablet formulations were utilized in investigating the potential binding characteristics of pectin harnessed from various okra genotypes (PC1-PC5) in Ghana. The pectin yields from the different genotypes ranged from 6.12 to 18.84%w/w. The pH of extracted pectin ranged from 6.39 to 6.92, and it had good swelling indices and a low moisture content. Pectin extracted from all genotypes were evaluated as binders (10, 15, and 20%w/v) and compared to tragacanth BP. All formulated tablets (F1-F18) passed the weight uniformity, drug content, hardness, and friability tests. Based on their crushing strength, tablets prepared with pectin from the various genotypes were relatively harder (P ≤ 0.05) than tablets prepared with tragacanth BP. Tablets prepared with pectins as binders at 10%w/v and 15%w/v passed the disintegration and dissolution tests with the exception of PC4 at 15%w/v. Incorporation of pectin from all genotypes (excluding PC5) as a binder at concentrations above 15%w/v (F13, F16, F14, and F15) produced tablets which failed the disintegration test and showed poor dissolution profiles. Thus, pectin from these genotypes can be industrially commodified as binders in immediate release tablets using varying concentrations.

Extraction and Characterization of Pectin from Lemon Waste for Commercial Applications

The objective of this paper was preliminary to extract and characterization of purified pectin from lemon wastes. Dry lemon waste was extracted applying citric acid solvent or water at various concentrations under a similar condition (85 ºC for 4 h). It was found that the highest yield of pectin (20.8% dry basis) was achieved using hot water extraction with an esterification degree of 47.8%. It contained 63.2 ± 0.74% galacturonic acid, followed by 17.4 ± 0.76% total sugar. The monosaccharides found in pectin were arabinose (2.7 ± 0.20%), galactose (2.3 ± 0.01%), glucose (1.4 ± 0.09%), mannose (0.4 ± 0.01%), fructose (0.4 ± 0.05%), and xylose (0.1 ± 0.01%). The found pectin had a high atomic weight of 2060 kDa with a wide polydispersity index of 4.41, decided by high-Performance Size Exclusion Chromatography (HPSEC). The extricated lemon waste pectin was grouped into low methoxyl pectin, depends on the methoxyl content and degree of esterification affirmed by Fourier transform infrared spectroscopy (FT-IR) and rheological properties. In conclusion, the discoveries of the study show that lemon waste can be investigated as a promising elective for the commercial manufacturing of pectin.

Chemical elucidation of an arabinogalactan from rhizome of Polygonatum sibiricum with antioxidant activities

Polygonatum sibiricum is traditionally used as Chinese medicine for immunity enhancement. Exploration of polysaccharides from Polygonatum species would provide a wider insight into the studies on their chemical structures and function activities. In this study, the alkali-extracted polysaccharide from P. sibiricum (PSP) was isolated and examined. The polysaccharide was firstly isolated by ion-exchange chromatography equipped with DE52 column, followed by isolated through Superdex-200 column. The obtained PSPJWA fraction was a homogenous one with average molecular weight of 141 kDa. The monosaccharide composition was galactose, arabinose and rhamnose in a ratio of 14:4:1. The glycosidic linkages of PSPJWA fraction were indicated to be Araf-(1→, →5)-Araf-(1→, →3,5)-Araf-(1→, Galp-(1→, →4)-Galp-(1→, →4,6)-Galp-(1→ and →2,4)-Rhap-(1→ residue by methylation analysis. NMR and enzymatic studies showed that PSPJWA was a novel arabinogalactan-type structure. PSPJW polysaccharides with different molecular weight and similar chemical structure had different antioxidant activities. Together, P. sibiricum polysaccharide has the potential to be a natural antioxidant.

Berry fruits as source of pectin: Conventional and non-conventional extraction techniques

Three non-conventional extraction techniques (enzyme-assisted with cellulase, citric acid ultrasound-assisted and enzyme-ultrasound-assisted treatment) and conventional citric acid extraction were applied to obtain pectin from raspberry, blueberry, strawberry and redcurrant, and were compared in terms of extraction yields and physicochemical properties of the extracted pectins. Except for pectin from raspberry, conventional citric acid extraction led to the highest extraction yield (~8%) and, for the same berries, the lowest pectin recovery was found for the extraction with cellulase (~4%). Regarding the structural characteristics of pectins, enzymatically extracted pectins from redcurrant and strawberry exhibited the highest levels of galacturonic acid (≥73%) whereas, in general, this monosaccharide was found from 51 to 69% in the rest of samples. Although, ultrasound-assisted extraction did not improve pectin yield, it minimized the levels of "non-pectic" components leading to the obtainment of purer pectin. The different monomeric composition and the wide range of molecular weight of the obtained pectins pointed out their usefulness in different potential food applications (e.g., thickening, gelling ingredients) and biological activities. This has been evidenced by the differences found in their physicochemical and techno-functional characteristics. Finally, it can be considered that the berries here studied are efficient sources of pectin.

Potential and Comparative Tablet Disintegrant Properties of Pectin Obtained from Five Okra Genotypes in Ghana

Okra pectin has been studied as a potential excipient in tablet formulations for pharmaceutical industries. Okra is widely grown and available in Ghana and other parts of the world. The prospective use of pectin from okra genotypes grown in Ghana as tablet disintegrants has not been reported. This study aims to determine the potential and comparative disintegrating properties of pectin from five okra genotypes (Abelmoschus esculentus L.) in Ghana using uncoated immediate release paracetamol tablet formulations. The yield of the pectin from the various genotypes ranged between 6.12 and 18.84% w/w. The extracted pectins had pH ranging from slightly acidic to almost neutral (6.39-6.92). Pectin from the various genotypes exhibited good swelling indexes (˃200%), varying solubility in different solvents, and low moisture content (˂20%). Elemental analysis of the extracted pectin from the various genotypes revealed very low levels of toxic metals and micronutrients. Pectin from the various genotypes was evaluated as disintegrants within concentrations of 5-10% w/w (F1-F18). Their disintegrating properties were compared to that of maize starch BP. All the formulated batches of uncoated immediate release paracetamol tablets (F1-F18) passed the following: uniformity of weight test, uniformity of dimensions, hardness, friability (˂1%), and drug content (95-105%). Significant differences (p ≤ 0.05) were observed between the hardness of the maize starch tablets and tablets formulated from pectin of the various genotypes. Pectin from all genotypes other than PC5 exhibited good disintegrating properties (D T  ˂ 15 min) and subsequently passed the dissolution profile test (≥70% release in 45 minutes). Tablets formulated with PC5 as disintegrants at all concentrations (5% w/w (F5), 7.5% w/w (F11), and 10% w/w (F17)) failed the disintegration and dissolution tests. Ultimately, pectins extracted from PC1, PC2, PC3, and PC4 can be commercially exploited as disintegrants in immediate release tablets.

Delineating the inherent functional descriptors and biofunctionalities of pectic polysaccharides

Pectin is a plant-based heteropolysaccharide macromolecule predominantly found in the cell wall of plants. Pectin is commercially extracted from apple pomace, citrus peels and sugar beet pulp and is widely used in the food industry as a stabilizer, emulsifier, encapsulant, and gelling agent. This review highlights various parameters considered important for describing the inherent properties and biofunctionalities of pectins in food systems. These inherent descriptors include monosaccharide composition, galacturonic acid content, degree of esterification, molecular weight, structural morphology, functional group analysis, and functional properties, such as water and oil holding capacity, emulsification, foaming capacity, foam stability, and viscosity. In this study, we also delineate their potential as a nutraceutical, prebiotic, and carrier for bioactive compounds. The biofunctionalities of pectin as an anticancer, antioxidant, lipid-lowering, and antidiabetic agent are also conceptually elaborated in the current review. The multidimensional characteristics of pectin make it a potential candidate for use in food and biomedical science.

Physicochemical and functional characteristics of polysaccharides from okra extracted by using ultrasound at different frequencies

In this study, single- (SFU) and dual-frequency (DFU) ultrasounds were used to extract polysaccharides from okra (Abelmoschus esculentus (L.) Moench) pods (OPSs), and the physicochemical characteristics, functional properties, and in vitro biological activities of the OPSs were comparatively evaluated. Results showed that ultrasonic extractions at different frequencies led to remarkable variations in extraction yields, chemical components, monosaccharide compositions, molecular weights (MWs), surface morphologies, and rheological properties of the OPSs but hardly affected their preliminary structural features and thermal stabilities. The OPS obtained through DFU at 40/60 kHz with the lowest MWs (0.85-14.93 × 10⁵ Da) and highest polyphenol content (7.38%) as well as loosest network structures showed superior antioxidant, cholesterol absorption and nitrite ion absorption capacities than the other OPSs, and the OPS extracted through SFU at 20 kHz with the highest carboxylate content (76.08%), MWs (7.28-32.83 × 10⁵ Da) and degree of esterification (30.7%) exhibited higher bile acid-binding capacity than the other OPSs.

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.

Preparation, characterization, antioxidant and anti-inflammatory activities of acid-soluble pectin from okra (Abelmoschus esculentus L.)

Currently, there are few studies on acid-soluble pectin from okra, especially in biological activity for antioxidant and anti-inflammatory. In this study, the antioxidant properties of acid-soluble okra pectin components and their anti-inflammatory were explored. Firstly, two acid-soluble okra pectic fractions, namely crude acid-soluble okra pectin (CAOP) and acid-soluble okra pectin (AOP), were obtained and exhibited structural and compositional variation. The two pectic fractions contained a low degree of esterification (42.0-46.5%) and a relatively high uronic acid content (31.6-37.3%). AOP was composed of galacturonic acid (79.1 mol/%), galactose (4.3 mol/%), rhamnose (14.5 mol/%) and xylose (2.1 mol/%), and the molecular weight was 92.8 kDa. Morphological and thermal properties of acid-soluble okra pectin components were also investigated. Compared to CAOP, AOP expressed better antioxidant activity, and suppressed the NO production in LPS-induced RAW 264.7 macrophages. All the above results indicated that AOP had the potential to act as a natural antioxidant or a functional anti-inflammatory food, which would broaden the development and utilization of okra resources.

Structural characterization, functional properties and antioxidant activities of polysaccharide extract obtained from okra leaves (Abelmoschus esculentus)

Polysaccharides have been isolated from okra pods (Abelmoschus esculentus), with little focus on the leaves. This study characterized a water-soluble polysaccharide isolated from okra leaves (OLP), and investigated its functional properties, for their potential applications. FT-IR and NMR spectroscopy were used to describe structural characteristics and the influence on functional properties was examined. The result revealed OLP as a low-molecular-weight polysaccharide (26.9 × 10³ g/mol^-1) consisting of galactose (~54 mol%), galacturonic acid (~29 mol%), rhamnose (~9mol%) and arabinose (~5mol%) as the primary sugars, and rhamnogalacturonan-I as the predominant structural unit. OLP was found to be an extensively-branched, highly acetylated, and unmethylated polysaccharide. OLP exhibited non-Newtonian flow behavior and showed comparable or superior functional properties such as thermal stability and emulsifying capacity, and higher antioxidant capacity than polysaccharide previously obtained from okra pods. This study presents a means of utilizing okra leaves as a new polysaccharide source, with potential applications in food-related industries.

The primary, secondary, and structures of higher levels of pectin polysaccharides

Pectin is a heteropolysaccharide abundant in the cell wall of plants and is obtained mainly from fruit (citrus and apple), thus its properties are particularly prone to changes occurring during ripening process. Properties of pectin depend on the string-like structure (conformation, stiffness) of the molecules that determines their mutual interaction and with the surrounding environment. Therefore, in this review the primary, secondary, and structures of higher levels of pectin chains are discussed in relation to external factors including crosslinking mechanisms. The review shows that the primary structure of pectin is relatively well known, however, we still know little about the conformation and properties of the more realistic systems of higher orders involving side chains, functional groups, and complexes of pectin domains. In particular, there is lack of knowledge on the influence of postharvest changes and extraction method on the primary and secondary structure of pectin that would affect conformation in a given environment and assembly to higher structural levels. Exploring the above-mentioned issues will allow to improve our understanding of pectin functionality and will help to tailor new functionalities for the food industry based on natural but often biologically variable source. The review also demonstrates that atomic force microscopy is a very convenient and adequate tool for the evaluation of pectin conformation since it allows for the relatively straightforward stretching of the pectin molecule in order to measure the force-extension curve which is directly related to its stiffness or flexibility.

Structural Properties, Bioactivities, and Applications of Polysaccharides from Okra [Abelmoschus esculentus (L.) Moench]: A Review

Okra [Abelmoschus esculentus (L.) Moench], as a kind of nutritive vegetable, is rich in flavonoids, polyphenols, polysaccharides, amino acids, and other bioactive substances and has various biological activities. As one of main bioactive components, okra polysaccharides (OPs), mainly comprising pectic polysaccharides, have various biological activities. OPs have been extensively investigated in recent years. Many studies characterized structures of OPs obtained by different extraction methods, which were confirmed to be rhamnogalacturonan-I-type polysaccharides in most cases. OPs have a thick and slimy texture, suggesting that they can be a promising source of texture modifiers for complex food matrices. They have various biological activities, such as antioxidant activity, immunomodulatory activity, hypoglycaemic activity, and improving intestinal function. Therefore, OPs may potentially serve as novel immunomodulators or an adjuvant for diabetic nephropathy. Up to now, there is no specific summary on the research progress of OPs. In this paper, the latest research progress on the extraction, purification, characterization, rheological properties, biological activities, and applications of OPs is reviewed, to provide the reference for the processing and comprehensive utilization of OPs in the future.

Polysaccharide from Lycium arabicum: Structural Features, in Vitro Antioxidant Activities and Protective Effect against Oxidative Damage in Human Erythrocytes

In this research work, a water-soluble polysaccharide (LAP) isolated from the fruits of Lycium arabicum was investigated. LAP contains carbohydrates (82.45±1.23 %), protein (1.56±0.21 %), and uronic acids (3.56±0.34 %). The analysis of the monosaccharide composition revealed the presence of rhamnose, arabinose, galactose, glucose and mannose in a molar ratio of 4.7 : 1.5 : 1 : 8.7 : 16.4 : 5.6. The extracted polysaccharide (PS) was considered as heterogeneous and highly branched by interpreting its GC/MS, FT-IR and NMR data. Crystallinity of LAP was inferred from its X-ray diffractometry (XRD) and Scanning Electron Microscopy (SEM) analysis. LAP exhibited an interesting stability at high temperatures (∼254 °C) and in a wide range of pH (3-9) deduced, respectively, from its DSC and zeta potential analysis. LAP displayed a strong antioxidant activity at low concentrations evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH)-radical scavenging, ferric reducing activity power (FRAP), free radical scavenging ability, superoxide radical-scavenging and hydroxyl radical-scavenging abilities. Inhibition of erythrocyte hemolysis and lipid peroxidation was also assessed. In 5 h, LAP treatment allowed the protection of the damaged erythrocytes caused by AAPH (2,2-azobis(2-amidinopropane) dihydrochloride), to reduce the level of malondialdehyde (MDA) as well as to increase the reduced glutathione (GSH) level.