Pectin Polymers Research Articles

Biological investigation of a novel nanocomposite based on functionalized graphene oxide nanosheets with pectin, silk fibroin and zinc chromite nanoparticles

For biotechnology applications, a novel nanobiocomposite was synthesized based on modification of graphene oxide (GO) by extracted silk fibroin (SF), natural polymer pectin (Pec) and zinc chromite (ZnCr2O4) nanoparticles (NPs). The structure and properties of hybrid nanobiocomposite GO-Pec/SF/ZnCr2O4 such as thermal stability, less toxicity, biocompatibility, antibacterial, and biodegradable were proved by using field emission scanning electron microscope (FE-SEM), Fourier-transformed infrared (FT-IR), Energy dispersive X-ray spectroscopy (EDS), thermal gravimetric analysis (TGA), and X-Ray diffraction (XRD). According to the biological features of substances, the GO-Pec/SF/ZnCr2O4 nanobiocomposite shows perfect results in MTT (83.71 %) and Hemolysis (16.52 %) assays. accordingly, mentioned properties of this nanobiocomposite can be used as a scaffold for medical applications.

OVERVIEW OF PECTIN AS AN EXCIPIENT AND ITS USE IN THE PHARMACEUTICAL DOSAGE FORM

Pectin is a polysaccharide that is abundant in nature and has promising uses in the pharmaceutical field. Pectin is resistant to digestive enzymes but pectin gel can swell in aqueous media and small amounts of compounds can be released into the gastrointestinal tract. This problem can be solved by developing pectin composites obtained from the incorporation of pectin polymers with other polymers. This article discusses the interaction of pectin with other polymers in various drug delivery systems. The method used in review articles is to review nationally and internationally published scientific journals obtained from Google, Google Scholar, Pubmed and Science Direct. From several related studies, delivery systems that have been developed and reported in the form of films, hydrogels, particulate systems and tablets. Other polymers such as Alginatee, protein, chitosan, gelatin and starch are known to improve the properties of pectin so that pectin composites can be used as controlled drug delivery. Thus, the development of other drug delivery systems with pectin composites becomes an opportunity and challenge in the future.

A locust bean and pectin polymer blend integrated with thio-bridged pyridinyl additive as a novel cobalt and copper gel electrolyte system for dye-sensitized solar cells

An intensive correlation has been attempted on 2-(pyridin-2-yl)-1-(4-(trifluoromethyl)phenyl)-1H-benzo[d]imidazole ligand-coordinated cobalt and copper metal complex electrolytes (Co2+/3+[ptpbi]3 and Cu1+/2+[ptpbi]2) with blend biopolymer electrolyte based on Locust Bean Gum and Pectin (LP) as a host matrix to enhance the performance of organic DPTCY sensitizer (2D-π-D′-A-π-A). Comparatively, the ligand coupled bulky CF3 acceptor on the para position of benzyl moiety-substituted 2-(pyridin-2-yl)-benzimidazole (on the N–H position) [ptpbi]-coordinated copper metal complex shows a higher redox potential (0.62 V vs NHE) compare to Co2+/3+ redox system. The photovoltaic performance of thio-bridged pyridinyl based organic compounds (MPP and DSP) with/without highly electron-donating substituents (methyl group) as an additive in QSSE host for dye-sensitized solar cell applications has been employed. A thorough investigation has been made for blending polysaccharide polymer-based electrolytes E1 to E4 through DSC, FTIR, UV–Vis spectroscopic techniques. The analysis of assembled device as [TiO2/DPTCY Dye/Mn+/m + redox/additive/LP blend biopolymer/Pt] has achieved a maximum PCE of 5.97% under 1 sun (100 mW cm−2) condition with 1.5AM. These results signify a record for copper complex with methyl-substituted thio-bridged pyridinyl (MPP) with higher efficiency. These devices had shown a higher chemical capacitance (6.06 × 10−6 F), recombination resistance (25.5 Ω), charge transfer resistance (5.67 Ω), ionic conductivity (1.568 (S cm−1) × 10−3), electron lifetime (48.97 ms), diffusion coefficient (2.63 × 10−7 cm−2 s), dielectric constant (2.76 × 102) and dielectric loss (4.41 × 103) compared with other substitution-based additives. These additives have trapped the diffusion of Cu2+ and Co3+ ion species has resulted in the constraint resistance and enhancement of the catalytic effect of the counter electrode. The higher charge relaxation time and a negative shift in the Quasi-Fermi level of TiO2 arise by correlating photocurrent and photovoltage in suppression of recombination reaction.

Kinetics of Plant‐derived Heteropolysaccharide Bioabsorption Characterized by Fluorescence‐based Microfluidics System

Plant‐derived structural polymer, pectin, is the “glue” between plant cells, a biomaterial with promising performance as a sealant on visceral organs. However, the nature of bioabsorption and biodurability of pectin remains unclear. Here, we investigate the feasibility of a quantitative microfluidic perfusion assay based on photochemical quenching, to define the kinetics of pectin bioabsorption.We hypothesize that fluorescent tracers embedded into pectin biopolymers will reliably reflect predictable kinetics patterns of bioabsorption including predictable trends when modifying the chemical species used in fluorescence quenching experiments.A fluorescent tracer, Fluorescein Sodium, was embedded into high methoxyl citrus pectin. Dried Fluorescein pectin films were placed into 24‐well plates, to monitor degradation via parallel microfluidics perfusion. This perfusion was performed via micro‐perfused exogenous 0.4% Trypan Blue, an anionic hydrophilic azo dye, which was delivered into porous matrix interfacing on pectin in each well. To assess biodurability, the fluorescence of perfused pectin under quenching by dye was monitored over time using a multi‐well plate fluorescence reader (Cytofluor 4000, PerSeptive Biosystems).Our data show that consistent trends in fluorescence result during quenching experiments. When un‐perfused, Fluorescein‐embedded pectin exhibited statistically insignificant change in quantum yield over 1 week (p=0.457), suggesting that results were not impacted by substantial photobleaching over the course of experimentation. To minimize interfacial flow artifact, 6µm porous matrix provided an effective interface for observable perfusion of azo dye into pectin. During micro‐perfusion, serial measurements of fluorescence in Fluorescein pectin demonstrated exponential decline in fluorescence intensity. This quenching of fluorescent signal from Fluorescein correlated with the progressive bioabsorption of the pectin polymer. Absorption was feasibly modulated by adjusting dye volumes used in perfusion.In this in vitro assay, plant‐derived pectin exhibits predictable decay characteristics and bioabsorption kinetics when incorporated with fluorescent tracers. These tracers not only provide a quantitative measure of biodurability, but also an opportunity for guided biochemical tuning of the complex biomaterial, to improve its performance as a potential therapeutic sealant.

Optical and dielectric characterization of biopolymer pectin based electrolytes with NaCl

Biopolymer pectin based polymer electrolytes with sodium chloride (NaCl) were prepared by solution casting method. Semi crystalline nature of pectin is reduced to reach the amorphous nature by addition of NaCl salt,investigated by X-ray diffraction analysis and XRD deconvolution technique. Investigation of FTIR and FTIR deconvolution exposed the occurrence of complexation and increment of free ion by addition of NaCl. The shifting of UV absorbance band of pectin demonstrates the optical properties of the prepared polymer electrolytes. Optical bandgap of pectin polymer electrolyte was decreased from 3.13 eV to 2.98 eV due to the electrons transition from valence band to conduction band. The measurements of dielectric constants were conceded out on these films in the frequency range 42–106 Hz from 303K to 373 K. From all these characterisation, 3 wt.% of NaCl doped polymer-salt complex system performed well.

Molecular Simulations to Understand the Moisture, Carbon Dioxide, and Oxygen Barrier Properties of Pectin Films.

Density functional theory and molecular dynamic simulations were used to understand the microscopic-level interactions of pectin-based thin films with moisture (H2O), carbon dioxide (CO2), and oxygen (O2). Galacturonic acid (GA), which forms ~65% of the smooth region of pectin polymer, was chosen for the current study. The electrostatic potential and Fukui function maps indicate that oxygen atoms of -OH groups of GA are the most reactive sites for electrophilic attack and hydrogen atoms on the carboxylic group (-COOH) are the reactive sites for nucleophilic attack. The GA molecule has shown strong interaction via hydrogen bonding with H2O (E= ~ 40 kJ/mol) followed by CO2 (E = ~ -13 kJ/mol). Nucleophilic O2 showed insignificant interaction with GA. Surface interaction, adsorption, and diffusion of sorbate molecules on the GA film followed the order of H2O >CO2 > O2. Molecular interaction studies provided atomistic insights into the weak moisture and high gas barrier properties of pectin films.

Eco-friendly pectin polymer film-based triboelectric nanogenerator for energy scavenging.

Inspired by the desire to solve the energy-related issues in remote sensing applications, internet of things, wireless autonomous devices, and self-powered portable electronic devices, triboelectric nanogenerators (TENGs) have been highly promoted. However, for use in the specified applications, especially in wearable and biomedical devices, environmental-friendly materials are required. Herein, an eco-friendly pectin polymer is used as a positive triboelectric material to fabricate a TENG with excellent output performance. Working in conjunction with a polyimide, the polyimide and microarchitected pectin (MA@pectin) polymer film-based TENG (PP-TENG) generated open circuit voltage (VOC), short circuit current (ISC), and charge density (QSC) of ∼300 V, 14 μA, and 70 μC cm-2, respectively, exhibiting remarkable enhancement compared to the TENG based on polyimide/pristine pectin polymer (VOC, ISC, and QSC of 170 V, 7.6 μA, and 47 μC cm-2, respectively) under similar operating conditions. The output performance of the PP-TENG is particularly reliant on the pectin concentration, indicating an optimum concentration of 9 wt%. The improved performance of the PP-TENG was systematically analyzed and explained in terms of pectin concentration, dielectric constant, and surface roughness. Furthermore, the PP-TENG can power portable electronic devices and light-emitting diodes to prove the capability of the TENG in practical applications. The fabricated PP-TENG is anticipated to be a sustainable energy harvester via a low-cost and facile approach.

Changes in biochemical properties and pectin nanostructures of juice sacs during the granulation process of pomelo fruit (Citrus grandis)

Postharvest granulation is a severe physiological disorder in citrus fruit that may be related to pectin metabolism. This study was designed to analyze the changes in fruit quality and pectin metabolism of pomelo fruit during granulation from expansion, gelation to lignification. Fruit quality showed a decrease starting from the gelation stage. Contents of water-soluble pectin, chelate-soluble pectin, sodium carbonate-soluble pectin and calcium, and activity of pectin methylesterase increased, while polygalacturonase activity decreased upon granulation. Atomic force microscopy analysis showed that both length and width of those three types of pectin molecules increased during granulation, accompanied by the decrease of linear structure molecules of pectin and the increase of pectin polymers, and multi-branched pectin tending to form cross-linked structure. Complex network of pectin might be remodeled during granulation process that immobilized the free water in juice sacs and induced the gelation occurrence, further promoted the granulation process.

Upcycling of steel slag for manufacture of Prussian-blue-encapsulated pectin beads and its use for efficient removal of aqueous cesium

Development of innovative technology for solid waste disposal, particularly the synthesis of novel energy and environmental materials via upcycling of solid wastes, is essential for boosting sustainable development in urban areas. In this study, we developed a novel synthesis method for Prussian-blue-encapsulated pectin beads (PB@PD) using Fe and Ca sources in steel slag (SS) and demonstrated its feasibility for the removal of Cs+ via batch and fixed-bed column reactors. Hydrochloric acid (HCl) was used for Fe and Ca dissolution in the SS suspension, and the extracted Fe and Ca were then used for the synthesis of Prussian blue and pectin polymer beads, respectively. The surface characteristics of PB@PD were determined through advanced microscopy and surface analyses, which confirmed the successful formation of a PB crystal structure and well-distributed PB particles in the cross-linked pectin structure. Batch isotherm adsorption experiments conducted using PB@PD revealed that the maximum adsorption capacity of Cs+ was 54.34 mg/g. PB@PD could be recycled up to four times and was very effective for Cs+ adsorption in artificial seawater. Furthermore, we successfully applied PB@PD as a filling material in a fixed-bed column reactor and obtained an effective adsorption capacity (41.75–43.9 mg/g) without any clogging problem during the continuous Cs+ treatment.

Avocado Peels and Seeds: Processing Strategies for the Development of Highly Antioxidant Bioplastic Films.

The industrial processing of avocados annually generates more than 1.2 million tons of avocado peels (APs) and avocado seeds (ASs) that have great potential in the production of active bioplastics, although they have never been considered for this aim until now. Separately, the APs and ASs, as well as a combination of avocado peels and seeds (APSs), were evaluated here for the first time for the preparation of antioxidant films, with application in food packaging. Films were prepared by casting, after their processing by three different methods: (1) hydrolysis in acid media, (2) hydrolysis followed by plasticization, and (3) hydrolysis and plasticization followed by blending with pectin polymers in different proportions (25 and 50 wt %). The results indicate that the combination of hydrolysis, plasticization, and pectin blending is essential to obtain materials with competitive mechanical properties, optical clarity, excellent oxygen barrier properties, high antioxidant activity, biodegradability, and migration of components in TENAX suitable for food contact applications. In addition, the materials prepared with APSs are advantageous from the point of view of the industrial waste valorization, since the entire avocado wastes are used for the production of bioplastics, avoiding further separation processes for their valorization.

Compartmentalization of Pectinase within Cellulose Hydrogel: An Efficient Technique to Enhance the Catalytic Properties of Pectinase for Industrial Applications

Pectinase catalyze the breakdown of pectin polymer and widely has been used in different industrial preparations such as fruit juice preparation, liquification and scarification of plant biomass as well as coffee and tea fermentation. In this study, the pectinase from Bacillus licheniformis was compartmentalized within cellulose beads hydrogel using encapsulation technique to make it reusable with easy recovery from reaction mixture. The compartmentalization improved catalytic properties of pectinase and ensured its reusability for continuous uses. It was observed that 5.0% cellulose concentration was enough to form stable cellulose hydrogel beads with retention of high relative of activity of pectinase. The hydrogel compartmentalization didn’t change the optima pH and temperature for maximum relative activity and both the hydrogel compartmentalized pectinase and free pectinase maximum relative at same pH and temperature but the hydrogel compartmentalization increased the stability of pectinase against various temperatures and pH, and hydrogel compartmentalized pectinase showed higher relative activities against various temperature and pH as compared to free pectinase. The hydrogel compartmentalization slightly reduced the affinity of pectinase toward the substrate (pectin) and hydrogel compartmentalized pectinase showed little bit higher Km value as compared to soluble pectinase. Cellulose hydrogel compartmentalization retained the pectinase activity for reutilization in different reaction preparation and hydrogel compartmentalized pectinase showed more than 80% of its original activity after three times reusing.

Plasmodiophora brassicae-Triggered Cell Enlargement and Loss of Cellular Integrity in Root Systems Are Mediated by Pectin Demethylation.

Gall formation on the belowground parts of plants infected with Plasmodiophora brassicae is the result of extensive host cellular reprogramming. The development of these structures is a consequence of increased cell proliferation followed by massive enlargement of cells colonized with the pathogen. Drastic changes in cellular growth patterns create local deformities in the roots and hypocotyl giving rise to mechanical tensions within the tissue of these organs. Host cell wall extensibility and recomposition accompany the growth of the gall and influence pathogen spread and also pathogen life cycle progression. Demethylation of pectin within the extracellular matrix may play an important role in P. brassicae-driven hypertrophy of host underground organs. Through proteomic analysis of the cell wall, we identified proteins accumulating in the galls developing on the underground parts of Arabidopsis thaliana plants infected with P. brassicae. One of the key proteins identified was the pectin methylesterase (PME18); we further characterized its expression and conducted functional and anatomic studies in the knockout mutant and used Raman spectroscopy to study the status of pectin in P. brassicae-infected galls. We found that late stages of gall formation are accompanied with increased levels of PME18. We have also shown that the massive enlargement of cells colonized with P. brassicae coincides with decreases in pectin methylation. In pme18-2 knockout mutants, P. brassicae could still induce demethylation; however, the galls in this line were smaller and cellular expansion was less pronounced. Alteration in pectin demethylation in the host resulted in changes in pathogen distribution and slowed down disease progression. To conclude, P. brassicae-driven host organ hypertrophy observed during clubroot disease is accompanied by pectin demethylation in the extracellular matrix. The pathogen hijacks endogenous host mechanisms involved in cell wall loosening to create an optimal cellular environment for completion of its life cycle and eventual release of resting spores facilitated by degradation of demethylated pectin polymers.

Tracking cell wall changes in wine and table grapes undergoing Botrytis cinerea infection using glycan microarrays.

The necrotrophic fungus Botrytis cinerea infects a broad range of fruit crops including domesticated grapevine Vitis vinifera cultivars. Damage caused by this pathogen is severely detrimental to the table and wine grape industries and results in substantial crop losses worldwide. The apoplast and cell wall interface is an important setting where many plant-pathogen interactions take place and where some defence-related messenger molecules are generated. Limited studies have investigated changes in grape cell wall composition upon infection with B. cinerea, with much being inferred from studies on other fruit crops. In this study, comprehensive microarray polymer profiling in combination with monosaccharide compositional analysis was applied for the first time to investigate cell wall compositional changes in the berries of wine (Sauvignon Blanc and Cabernet Sauvignon) and table (Dauphine and Barlinka) grape cultivars during Botrytis infection and tissue maceration. This was used in conjunction with scanning electron microscopy (SEM) and X-ray computed tomography (CT) to characterize infection progression. Grapes infected at veraison did not develop visible infection symptoms, whereas grapes inoculated at the post-veraison and ripe stages showed evidence of significant tissue degradation. The latter was characterized by a reduction in signals for pectin epitopes in the berry cell walls, implying the degradation of pectin polymers. The table grape cultivars showed more severe infection symptoms, and corresponding pectin depolymerization, compared with wine grape cultivars. In both grape types, hemicellulose layers were largely unaffected, as was the arabinogalactan protein content, whereas in moderate to severely infected table grape cultivars, evidence of extensin epitope deposition was present. Specific changes in the grape cell wall compositional profiles appear to correlate with fungal disease susceptibility. Cell wall factors important in influencing resistance may include pectin methylesterification profiles, as well as extensin reorganization.

Silica-coated calcium pectinate formulations for controlling carbendazim release: water and soil release studies

This study aims to encapsulate the fungicide carbendazim using a biodegradable polymer (pectin). First, we have obtained calcium pectinate beads (CPG-Carb) by ionotropic gelation using calcium ions as a crosslinking agent. These beads were then coated with silica starting from tetraethoxysilane (TEOS), by a sol-gel process to form hybrid beads (CPG-Carb-SG). The morphology, composition and structure of both beads were characterized and the controlled release assays of the fungicide were studied in both water and soil columns. The encapsulation efficiency for CPG-Carb was slightly higher (75%) compared to CPG-Carb-SG (67%) due to carbendazim loss during the impregnation and condensation steps. The release rate in water and soil columns was about 4 times lower for CPG-Carb-SG than CPG-Carb demonstrating the efficiency of the silica coating to delay the release of carbendazim. Moreover, the release of CPG-Carb-SG is due to the erosion of the silica layer during the first two weeks. After this period, the silica layer was degraded, and the release is then controlled by the swelling of the organic part of the bead as observed for CPG-Carb. Finally, the biodegradability of the pectin, and the release profile make such systems promising candidates for sustained and economical pesticide delivery systems.

Characteristics and Release Profile : Formula of Insulin Nanoparticles using Medium Molecular Weight Chitosan and Pectin Polymers

Insulin is a macromolecular polypeptide hormone with low drug stability and permeability along the digestive tract. The nanoparticle delivery system has been proven to be able to increase the bioavailability of per-oral insulin. However, the formulation of insulin nanoparticles using chitosan and pectin polymers has not been widely studied. The purpose of this research is to figure out the physical characteristics and profile of insulin release from nanoparticle formulas made with ionic gelation techniques using chitosan and pectin polymers. The 0.1% insulin nanoparticle formula is made with variations of 2 levels of medium molecular chitosan and pectin concentrations to obtain 4 formulas, i.e. F1 (0.01%; 0.1%), F2 (0.03%; 0.1%), F3 (0.01%; 0.2%), and F4 (0.03%; 0.2%). The optimum formula is determined by the factorial design method contained in the Design Expert program using response characteristics in the form of percentage of the entrapment efficiency and zeta potential value. The selected formula is then tested for particle size and shape, and insulin release profile in vitro. The particle size and morphology are observed with TEM (Transmission Electron Microscope), while the insulin release profile is determined on HCl buffer media pH 1.2 and PBS pH 6.8. The optimization results of the formula show that F1 is the optimum formula with a desirability value of 0.786. The selected formula shows that the entrapment efficiency is 57.66%, the zeta potential is 12.0 mV, the shape of particles is spherical, and the size is <500 nm. In vitro studies show the profile of insulin release from the matrix following the Weibull kinetics model on HCl and Korsmeyer-Peppas media on PBS media, using the Fickian diffusion method. Overall, the insulin nanoparticles obtained have met the expected characteristic of the nanoparticles.

Biodegradable film of black mulberry pulp pectin/chlorophyll of black mulberry leaf encapsulated with carboxymethylcellulose/silica nanoparticles: Investigation of physicochemical and antimicrobial properties

In this study, pectin was extracted from black mulberry fruit pulp and chlorophyll was extracted from black mulberry leaves. The extracted chlorophyll was encapsulated with carboxymethylcellulose (CMC). Black mulberry pectin/chlorophyll of black mulberry leaf encapsulated with carboxymethylcellulose/silica nanoparticles was prepared (Pec/Ch-CMC/SiO2). The physicochemical, mechanical and antimicrobial properties of the prepared films were investigated. SEM, FTIR, TGA and XRD techniques were used to study the structure of the films. According to the results, silica increased the thickness and decreased the moisture and solubility of the films. Increasing the amount of CMC in the capsules used in the film increased the thickness, moisture and solubility of the films. Silica increased the tensile strength of the film and reduced the flexibility of the film, while CMC reduced the tensile strength and increased the flexibility of the film. Chlorophyll and silica greatly increased the antioxidant properties of the film. Encapsulated chlorophyll and silica increased the antibacterial properties of the film against Escherichia coli and Staphylococcus aureus. SEM images showed that by simultaneously adding encapsulated chlorophyll and silica to the pectin structure, almost all gaps in the pectin surface were filled. According to the FTIR spectra, electrostatic interactions between pectin polymer chains with encapsulated chlorophyll and silica were confirmed. According to TGA results, the simultaneous addition of encapsulated chlorophyll and silica to the film increases the thermal stability of the film. According to the results, the pure pectin film has a semi-crystalline structure that the addition of silica and encapsulated reduces its crystalline structure.

Continuous Clarification of Barberry Juice with Pectinase Immobilised by Oxidized Polysaccharides.

SUMMARYResearch backgroundBarberry juice is a rich source of bioactive compounds and shows different health properties such as antioxidant and anticancer activities. Clarification, as the removal process of suspended material, is an important step in the production of fruit juice due to its significant effect on the appearance, flavour and commercialisation of juice. Pectinase is the most important enzyme applied in juice clarification that breaks down the pectin polymer structure and reduces the undesirable turbidity. Pectinase immobilisation is a way to overcome free enzyme drawbacks such as instability, high cost, the difficulty of recovery and recyclability. Also, continuous clarification process which is highly preferred in fruit juice industry is not possible without enzyme immobilisation.Experimental approachPectinase enzymes were immobilised on the functionalised glass beads (glass bead with (3-aminopropyl)triethoxysilane) by glutaraldehyde, polyaldehyde derivatives of pullulan and kefiran and the barberry juice was clarified in the batch and continuous processes in a packed bed reactor (PBR). Also, the effect of clarification on the physicochemical and antioxidant properties of the barberry juice samples was evaluated.Results and conclusionsThe optimum conditions for clarification in the PBR were: flow rate 0.5 mL/min, temperature 50 °C and treatment time 63 min. Clarification led to a decrease in turbidity, pH, total soluble solid content, viscosity, total phenolic content and antioxidant activity of the juice samples. Also, this process increased the clarity, acidity, reducing sugar concentration and the lightness parameter of the barberry juice. The greatest effect of clarification on the studied properties of barberry juice was related to the pectinase immobilised by the polyaldehyde of kefiran in the continuous process and both new cross-linkers (polyaldehyde derivatives of pullulan and kefiran) immobilised the enzyme better than the common cross-linker (glutaraldehyde).Novelty and scientific contributionFor the first time, barberry juice was clarified with pectinase immobilised by polyaldehyde derivatives of pullulan and kefiran and the obtained results showed that the pectinase immobilisation by these new cross-linkers was much more efficient than by the glutaraldehyde as a common cross-linker. These findings can be of use for an industrialised production of fruit juices.

Recent advances of fabricated and modified Ag, Cu, CuO and ZnO nanoparticles by herbal secondary metabolites, cellulose and pectin polymers for antimicrobial applications

Antibiotic resistance is a major hindrance to defeat pathogenic bacteria and fungi particularly in patients with immunodeficiency diseases. Recently, antimicrobial application of medicinal plant species and herbal polymers including cellulose and pectin to synthesize and modify metal nanoparticles (MNPs) and metal oxide nanoparticles (MONPs) has had more attention. Several advantages involving high accessibility, eco-friendliness, feasible preparation, biocompatibility, and biodegradability are found to these polymers. By these methods, antifungal and antibacterial anti-infective abilities of NPs can be improved owing to the antimicrobial activities of primary and secondary metabolites of medicinal plants. Among the MNPs/MONPs, Ag, Cu, CuO and ZnO NPs have displayed more antimicrobial capacities because of their unique properties such as reactive oxygen species (ROS) production. Therefore, recent advances and challenges related to antibacterial and antifungal effects of three promising NPs are presented in this review to obtain a future viewpoint of anti-infective therapy.

Kinetics of Pectin Reactions in Apple Pomace During Hydrothermal Treatment

The kinetics of pectin reactions in apple pomace were modelled preparatory to developing a time-temperature operating map for quantity and quality of solubilized pectin and other reactions in apple pomace. This graph can be used for selecting suitable time-temperature conditions for hydrothermal treatments to ensure a safe product with expected quality. Kinetics were measured for the major reactions in apple pomace heated at 90–140 °C for 0–210 min, in particular for the solubilization and depolymerization reactions of pectin. Maximum levels of soluble pectin (~ 605 μmol galacturonic acid/g dry pomace) were observed when heating pomace (diluted 1:2) at 130 and 140 °C for 15 and 7 min, respectively. Acid hydrolysis and β-elimination reactions showed temperature-dependent behaviour, with activation energies of 81 and 65 kJ/mol, respectively. Heating at temperatures ≥ 110 °C resulted in degradation of soluble pectin into ethanol-soluble galacturonic acid. Depolymerization reactions of pectin occurred at non-esterified sites within the pectin polymers, as suggested by the high degree of esterification of the remaining insoluble pectin.

Structure and composition of blueberry fiber pectin and xyloglucan that bind anthocyanins during fruit puree processing

Blueberry is a well-known source of antioxidants and prebiotic dietary fiber yet the fate of these health-beneficial ingredients during fruit processing it is not understood. Detailed composition and structure of blueberry pomace (PF) remaining after commercial blueberry fruit puree processing, as well as the water soluble and water insoluble fractions, were determined. The PF was comprised of dietary fiber (60.8%) that was largely insoluble (46.2% vs. 14.6% soluble dietary fiber) pectin, xyloglucan, arabinoxylan and mannan polysaccharides, fructose (11.22%) and glucose (10.37%) free sugars, protein (9%), fat (5%), and anthocyanins (6444.5 μg/g). The most abundant anthocyanins detected in PF were malvidin 3-arabinoside and peonidin 3-glucoside and the pectin was determined to be methyl-esterified and acetylated rhamnogalacturonan I with a 4,5-unsaturated function at the non-reducing end based on oligosaccharide structural analysis. Blueberry PF xyloglucan oligosaccharide side chain structures included xylose, arabinose and galactose consistent with arabino-xyloglucan structure. Microwave-assisted extraction of blueberry PF (pH 2 for 10 min at 80 °C) was performed to more clearly elucidate pectin structure, and revealed a pectin polymer with high molar mass (1072 kDa) and viscosity that was dependent upon the molar mass. A random coil shape was confirmed for both the blueberry PF and microwave extracted blueberry pectin, which agreed with previous reports that flexible blueberry pectin contributes to strong anthocyanin binding. In summary, the blueberry pomace anthocyanin content was slightly higher than that reported for fresh whole blueberry fruit, which suggests that most blueberry anthocyanins adhered to the pomace fiber, and most likely the insoluble pectin, during and after processing.