Pectin Group Research Articles

Development and biochemical characterization of freeze-dried guava powder fortified with Lactobacillus plantarum.

Guava (Psidium guajava L.) is one of the most nutrient-dense fruits, which is native to tropical and subtropical regions of the world. The processing of value-added products from guava has not been carried out on a scale similar to some other fruits, which offers an opportunity to fully exploit the potential of this fruit, such as guava-based nutraceutical food products. The objectives of the present study were to develop freeze-dried guava powders (FDGPs) from two guava varieties (white and pink) and characterize their physico-chemical and nutritional properties. FDGP was also incorporated with probiotic strains of Lactobacillus plantarum, to develop a healthy nutraceutical probiotic supplement. Functional groups assessed by Fourier transform infrared (FTIR) spectroscopy exhibited the existence of strong C-Br stretch, O-H stretch, and C=C stretch vibrations; however, scanning electron micrograms (SEMs) showed the flaky structure indicating the presence of starch, dietary fibers, and esterified groups of pectin. Significant mineral concentrations (mg/100g) of potassi-um (323-362), magnesium (26.2-28.8), zinc (0.43-0.51), and iron (0.52-0.63) were observed in FDGPs. The FDGP samples from both guava varieties had high levels of crude fiber (43.94-46.29%), vitamin C (2.27-2.49mg/g), and phenolic compounds (57.50-61.86mgGAE/g) as well as significant antioxidant properties. Fortification of FDGP with L. plantarum strains produced significant results in terms of probiotic viability that was nearly maintained at 108CFU/g up to 60 days in the final product. The viability of probiotics proved that FDGP is a good carrier of prebiotics and can be utilized as a potent probiotic supplement.

Influence of in vitro pectin fermentation on the human fecal microbiome and O-glycosylation of HT29-MTX cells

Pectin is a structurally complex heteropolysaccharide that affects intestinal microorganisms and mucin O-glycans. The present study employed an in vitro model to investigate dynamic changes in microbiota during pectin fermentation. Residual pectin fragments arising from its fermentation were applied to HT29-MTX cells to study the effect of pectin structure on mucin O-glycosylation. Prevotella, Bacteroides, and Parabacteroides were found to preferentially degrade galactose, arabinose, and on the rhamnogalacturonan RG-I side chain region and methyl esterification groups of pectin. Bifidobacterium, Enterococcus, Megamonas, and Dorea metabolized the galacturonic HG region on pectin to produce butyrate. All pectin fragments were found to up-regulate total O-glycans (1.55–2.73 fold) and neutral O-glycans (1.11–1.49 fold) on HT29-MTX mucins. The large HG fragment (81.04 kDa) increased significantly the amount of non-fucosylated glycans (by 2.46-fold); whereas the small HG fragment (16.02 kDa) promoted fucosylated (by 9.25 fold), and especially di-fucosylated O-glycans. Collectively, these results demonstrate that gut microorganisms degrade pectin fragments in the following order of utilization: RG-I, RG-II, and HG. The small fragment of HG improves the expression of fucosylated O-glycans in HT29-MTX cells, mainly owing to an increase in di-fucosylated O-glycans.

Fabrication of Anatomically Equivalent Pectin-Based Multifilament Nerve Conduits.

Reuniting denuded nerve ends after a long segmental peripheral nerve defect is challenging due to delayed axonal regeneration and incomplete, nonspecific reinnervation, as conventional hollow nerve guides fail to ensure proper fascicular complementation and obstruct axonal guidance across the defects. This study focuses on fabricating multifilament conduits using a plant-derived anionic polysaccharide, pectin, where the abundant availability of carboxylate (COO-) functional groups in pectin facilitates instantaneous sol-gel transition upon interaction with divalent cations. Despite their advantages, pectin hydrogels encounter structural instability under physiological conditions. Hence, pectin is conjugated with light-sensitive methacrylate residues (49.8% methacrylation) to overcome these issues, enabling the fabrication of dual cross-linked multifilament nerve conduits through an ionic interaction-driven, template-free 3D wet writing process, followed by photo-cross-linking at 525 nm. The anatomical equivalence including peri-, epi-, and endoneurium structures of the customized multifilament conduits was confirmed through scanning electron micrographs and micro-CT analysis of rat and goat sciatic nerve tissues. Furthermore, the fabricated multifilament nerve conduits demonstrated cytocompatibility and promoted the expression of neuron-specific intermediate filament protein (NF-200) in PC12 cells and neurite outgrowth of 16.90 ± 1.82 μm on day 14. Micro-CT imaging of an anastomosed native goat sciatic nerve with an 8-filament conduit demonstrated precise fascicular complementation in an ex vivo interpositional goat model. This approach not only eliminates the need for a suture-intensive ligation process but also highlights the customizability of multifilament conduits to meet patient- and injury-specific needs.

Impact of diverse mineral hardness in electrodialysis water on the ionotropic gelation mechanism of low methoxyl pectin

In this study, the effect of desalinated lava seawater via electrodialysis (ED water) on the formation and properties of low methoxyl pectin (LMP) gels was investigated. Additionally, the syneresis, microstructure, gelation mechanism, and thermostability of the gel samples were analyzed. When the ED water content exceeded 25 %, pectin gels with viscosities and textures that differed from those of the sol were formed. The highest gel hardness (9.38 N) was observed when 50 % ED water was mixed with LMP. However, when 75 % ED water was added, the pore size of the LMP gel became the largest, and excess water was released from the gel, resulting in a weak gel strength (4.98 N). The formation and properties of the gel structure were found to be mainly due to the ionic bonds between the minerals in the ED water and the free carboxyl groups of pectin, and it was confirmed that the hydrogen bonds within the pectin chains also had an effect. These results suggest that the interaction between the ED water and LMP can be widely used in various industrial fields, including low-sugar gels or viscosity-enhancing agents with diverse rheological properties.

Enhanced water absorption in pectin-chitosan hydrogel via modification with deep eutectic solvent: Optimisation and characterisation

Natural polymers are widely available, nontoxic, and biodegradable but have lower absorption when used to create hydrogels. Thus, a new modification of hydrogel combining pectin and chitosan was developed using choline chloride-based deep eutectic solvents (DESs) with ethylene glycol (DES1), glycerol (DES2), and acetic acid (DES3) called eutectogel. DES was added due to the hydrophilic site, which can increase water absorption. The eutectogel with each DES, including control (without DES), were optimized in their ratio of pectin to chitosan (0.5:1, 1:1, 1.5:1, and 2:1) and DES concentration (10 %, 20 %, and 30 %) to obtain the highest water absorption capacity (WAC). All developed gels showed the highest WAC at a ratio 0.5:1 of pectin to chitosan, with 20 % each of DES1, DES2, and DES3 labeled as E20, G20, and A20 having WAC values of 16.02, 13.50, and 12.50 g/g, respectively, owing to the existence of additional hydrophilic sites from DES within the gel for water binding. While the WAC value for the control was 6.2 g/g, this study proves the ability of DES to increase the WAC of E20, G20, and A20 more than two times compared to the control. E20 showed the highest water sorption because of the shorter and smaller size of ethylene glycol in DES1, with two less hindered hydroxyl groups efficiently binding with water molecules compared to glycerol and acetic acid. The interactions were observed through FTIR analysis, specifically in the amino groups of chitosan and carboxyl groups of pectin at the peak of 1636 to 1642 cm−1, which served as indicators of the electrostatic interaction with the modified DES and peak 3335 to 3350 cm−1 indicated of hydrogen bonding. The hydrogen bonding was also confirmed via DSC thermal analysis at 164.06°C to 188.44 °C. Characterization with FTIR, UV–Vis, and DSC confirmed the successful integration of DES, and it revealed that the new hydrogels had better transparency and thermal stability, with E20 showing the best overall performance in enhanced water absorption.

Effect of pectin modification on the properties of cellulose nanofibrils prepared from citrus peel

Cellulose nanofibrils (CNFs) from non-woody biomass, including citrus peel (CpCNFs), are promising naturally occurring nanomaterials; however, their properties depend on the composition of non-cellulosic components, including pectin. In this study, the effects of pectin modifications on CpCNFs were examined, including demethylesterification using alkaline treatment and enzymatic degradation of pectin using pectinase. CpCNFs could be redispersed in water with little aggregation after drying; however, the redispersibilities of both alkaline-treated (AT-CpCNFs) and pectinase-treated CpCNFs (PT-CpCNFs) were improved. Both AT-CpCNFs and PT-CpCNFs exhibited higher viscosity than untreated CpCNFs (UT-CpCNFs); redispersion in water after drying further increased the viscosity. A quartz crystal microbalance revealed that interactions between AT-CpCNFs were barely detectable, and interactions between PT-CpCNFs were stronger than those between UT-CpCNFs. The increase in the carboxylate groups of pectin due to demethylesterification in AT-CpCNF may have increased the viscosity and reduced the interactions between AT-CpCNFs, explaining the improved redispersibility. The increase in the viscosity of PT-CpCNFs may be attributed to the increased purity of CNFs, which is assumed to be more viscous than pectin. Our results show that the properties of CpCNFs are affected by the structure, properties, and content of pectin and can be controlled by pectin modification.

Pectin-nano zero valent iron nanocomposites for efficient heavy metal removal and bactericidal action against waterborne pathogens — Innovative green solution towards environmental sustainability

This study investigated the effectiveness of a pectin-nano zero-valent iron-based nanocomposite in adsorbing heavy metals in bimetallic form (chromium‑lead mixture), along with assessing its antibacterial properties. The nanocomposite was synthesized using a straightforward dispersion method, employing eco-friendly components like biocompatible pectin sourced from banana peels and nano-scale zero-valent iron. Analytical characterization confirmed the formation of stable, nano-crystalline particles with active interactions between the functional groups of pectin and nano iron. Batch adsorption experiments optimized various parameters such as pH, adsorbent dosage, contact time, metal ion concentration, and temperature to enhance bimetal removal from water. The optimal conditions were determined as pH 8.0, a temperature of 40 °C, 1.0 g/L adsorbent dosage, 75 mg/l initial bimetal concentration, and a contact time of 30 min. Further assessments revealed that the nanocomposite did not induce phytotoxic or ecotoxic effects, confirming its non-toxicity and environmental safety. Biocompatibility studies conducted using zebrafish models showed no adverse effects on hatching, survival, or heart rate. These findings underscore the potential of the nanocomposite as a sustainable and efficient solution for heavy metal remediation in water treatment process.

Benefits of maternal pectin supplementation in gestation diet on vaginal microbiota of sows and intestinal health of newborn piglets.

Pectin is a proven prebiotic and widely used in human health products. This study aims to assess the impact of dietary pectin supplementation during gestation on sow vaginal microbiota and the offspring's intestinal composition. Thirty sows were randomly allocated to two groups and fed a standard diet (CON) or a standard diet supplemented with 3 g/kg pectin (PEC). Blood, feces, and vaginal swab samples from the sows and blood, intestines issue, and colonic content samples from the offspring were collected and analyzed. The results indicate that the relative abundance of vaginal Lactobacillus was notably enhanced in the PEC group and fecal β-glucuronidase (β-G) activity and plasma 17β-estradiol (E2) concentration were also significantly increased in the PEC group. Newborn piglets were found to host different microbial communities as well. At the phylum level, Proteobacteria dominated in the CON group, and Firmicutes was predominant in the PEC group. Newborn piglets in the PEC group had a lower interleukin-6 (IL-6) concentration in their plasma. The expression of intestinal cytokines of offspring was improved as well. Villus height and villus height/crypt depth (V/C) in the PEC group were extremely higher than those in the CON group. In conclusion, dietary pectin supplementation can be of benefit to both sows and newborn piglets.

CD-MOF-1 Growth on Polysaccharide Gels through Only C2-OH/C3-OH or C5-O/C6-OH Group Formed Four-Coordinated K+ Ions for Developing Porous Biogels.

The γ-cyclodextrin (γ-CD) metal-organic frameworks (CD-MOF-1) consist of γ-CD and potassium (K+) ions through coordinating an eight-coordinated K+ ion with two C5-linked oxygen and C6-linked hydroxyl (C5-O/C6-OH) groups in the primary faces of adjacent γ-CD units and two C2- and C3-linked hydroxyl (C2-OH/C3-OH) groups in the secondary faces. Herein, we found polysaccharide gels with only C2-OH/C3-OH or C5-O/C6-OH groups in pyranoid rings can form four-coordinated K+ ions and then coordinate γ-CD in a KOH solution for CD-MOF-1 growth. Exposure of C2-OH/C3-OH or C5-O/C6-OH groups in polysaccharide gels is important to form active four-coordinated K+ ions. Mechanism supporting this work is that four-coordinated K+ ion sites are first formed after coordinating C2-OH/C3-OH groups in pectin and then coordinating C5-O/C6-OH groups in the primary faces of γ-CD units. Alternatively, four-coordinated K+ ions with C5-O/C6-OH groups in chitosan can coordinate the C2-OH/C3-OH groups in the secondary faces of γ-CD units. Mechanism of CD-MOF-1 growing on pectin and chitosan gels through the proposed four-coordinated K+ ions is also universally applicable to other polysaccharide gels with similar C2-OH/C3-OH or C5-O/C6-OH groups such as alginate gel. Based on this mechanism, we developed pectin and chitosan gel-based CD-MOF-1 composites and exemplified applications of them in antibacterial and organic dye removal. To help future research and applications of this mechanism, we share our theoretical assumption for further investigations that any matrices with an ortho-hydroxyl carbon chain or ortho-hydroxyl ether structures may form four-coordinated K+ ions for CD-MOF-1 growth. The proposed mechanism will broaden the development of novel CD-MOF-1 composites in various fields.

OPTIMAL CONDITIONS FOR EXTRACTING HIGH-QUALITY PECTIN FROM WATER HYACINTH (Eichhornia crassipes) FOR LESS SOLUBLE HYDROGEL PRODUCTION

The research aimed to extract high-quality pectin from water hyacinth for less soluble hydrogel production. The product adds value to water hyacinth waste and helps solve environmental problems. The high degree of esterification pectin can be prepared as a hydrogel, which can be used in various pollution treatment applications. The quality of pectin depended on raw materials and extraction conditions. The optimum condition was initially predicted using the response surface method (RSM). Three extraction variables were studied, including pH 1.0-4.0, temperature 50-110ºC, and extraction time 30-240 min. A total of seventeen runs including five replicate runs were studied. Functional groups of pectin were studied using Fourier Transform Infrared spectrophotometry. The degree of esterification and emulsifying properties were determined for assessing the quality of extracted pectin. The result revealed that the extraction conditions strongly affected both the yield and the quality. The condition of pH 2.5, 110ºC, and 30 minutes had the highest degree of esterification of 94.13 % but low yield (1.42%). On the other hand, under the conditions of pH 1.0, 110ºC, and 135 min extract time had the highest yield of 3.85% (about 76.6% of pectin content) however the degree of esterification is low at 43.25 %. Two mathematical models were proposed for yield and number of ester groups. The result will be used for the selection of high-quality pectin to produce insoluble hydrogel for pollution treatment in the future.

Flotation Separation of Cassiterite from Calcite Using Low-Molecular-Weight Citrus Pectin as Depressant

This paper presents the development of an environmentally friendly, small molecular depressant citrus pectin for improving the recovery of cassiterite resources. Citrus pectin extracted from citrus peel was utilized as the depressant, and it demonstrated significant potential in separating calcite from cassiterite in micro-flotation tests. The molecular weight of the citrus pectin extracted in this paper decreased from 11,485,412 Da to 32,959 Da compared to commercial pectin, resulting in the depressant efficiency of the reagent. The results of a zeta potential and adsorption test indicated that citrus pectin had less and weaker adsorption on the cassiterite surface and could be replaced with NaOL. The chemical adsorption process of citrus pectin on the surface of calcite was determined through FTIR spectroscopy analysis. XPS analysis results indicated that the interaction between the carboxyl groups of citrus pectin and calcium atoms enables adsorption to occur. The AFM revealed that citrus pectin displayed a uniform and dense pattern of point-like adsorption on the surface of calcite. Micro-flotation experiments showed that cassiterite recovery of 80% can be obtained at a citrus pectin dosage of 10 mg/L. Citrus pectin has the advantages of being low-cost, highly selective, and environmentally suitable, making it a promising alternative to conventional reagents.

Endophytic non-pathogenic Fusarium oxysporum reorganizes the cell wall in flax seedlings.

Flax (Linum usitatissimum) is a crop producing valuable products like seeds and fiber. However, its cultivation faces challenges from environmental stress factors and significant yield losses due to fungal infections. The major threat is Fusarium oxysporum f.sp lini, causing fusarium wilt of flax. Interestingly, within the Fusarium family, there are non-pathogenic strains known as biocontrols, which protect plants from infections caused by pathogenic strains. When exposed to a non-pathogenic strain, flax exhibits defense responses similar to those seen during pathogenic infections. This sensitization process activates immune reactions, preparing the plant to better combat potential pathogenic strains. The plant cell wall is crucial for defending against pathogens. It serves as the primary barrier, blocking pathogen entry into plant cells. The aim of the study was to investigate the effects of treating flax with a non-pathogenic Fusarium oxysporum strain, focusing on cell wall remodeling. The infection's progress was monitored by determining the fungal DNA content and microscopic observation. The plant defense response was confirmed by an increase in the level of Pathogenesis-Related (PR) genes transcripts. The reorganization of flax cell wall during non-pathogenic Fusarium oxysporum strain infection was examined using Infrared spectroscopy (IR), determination of cell wall polymer content, and analysis of mRNA level of genes involved in their metabolism. IR analysis revealed reduced cellulose content in flax seedlings after treatment with Fo47 and that the cellulose chains were shorter and more loosely bound. Hemicellulose content was also reduced but only after 12h and 36h. The total pectin content remained unchanged, while the relative share of simple sugars and uronic acids in the pectin fractions changed over time. In addition, a dynamic change in the level of methylesterification of carboxyl groups of pectin was observed in flax seedlings treated with Fo47 compared to untreated seedlings. The increase in lignin content was observed only 48 hours after the treatment with non-pathogenic Fusarium oxysporum. Analysis of mRNA levels of cell wall polymer metabolism genes showed significant changes over time in all analyzed genes. In conclusion, the research suggests that the rearrangement of the cell wall is likely one of the mechanisms behind flax sensitization by the non-pathogenic Fusarium oxysporum strain. Understanding these processes could help in developing strategies to enhance flax's resistance to fusarium wilt and improve its overall yield and quality.

Novel films of pectin extracted from ambarella fruit peel and jackfruit seed slimy sheath: Effect of ionic crosslinking on the properties of pectin film

Here, we prepared ionically crosslinked films using pectin extracted from agro-wastes, specifically ambarella peels (AFP) and jackfruit seed slimy sheath (JFS). Physiochemical properties of pectins, including moisture content, molecular weight (Mw), degree of esterification (DE), and galacturonic acid (GA), were analyzed. Optimal extraction was determined, i.e., citric acid concentration 0.3 M, time 60 min, solid/liquid ratio 1:25, and temperature 90 °C for AFP or 85 °C for JFS. Pectin yields under these conditions were 29.67 % ± 0.35 % and 29.93 ± 0.49 %, respectively. AFP pectin revealed Mw, DE, and GA values of 533.20 kDa, 67.08 % ± 0.68 %, and 75.39 ± 0.82 %, while JFS pectin exhibited values of 859.94 kDa, 63.04 % ± 0.47 %, and 78.63 % ± 0.71 %, respectively. The pectin films crosslinked with Ca2+, Cu2+, Fe3+, or Zn2+ exhibited enhanced tensile strength and Young's modulus, along with reduced elongation at break, moisture content, water solubility, water vapor permeability, and oxygen permeability. Structural analyses indicated metal ions were effectively crosslinked with carboxyl groups of pectin. Notably, the Cu2+-crosslinked film demonstrated superior water resistance, mechanical properties, and exhibited the highest antioxidant and antibacterial activities among all tested films. Therefore, the pectin films represent a promising avenue to produce eco-friendly food packaging materials with excellent properties.

Preparation, physicochemical characterization and swelling properties of composite hydrogel microparticles based on gelatin and pectins with different structure

Composite hydrogel microparticles based on pectins with different structures (callus culture pectin (SVC) and apple pectin (AU)) and gelatin were developed. Hydrogel microparticles were formed by the ionotropic gelation and electrostatic interaction of COO− groups of pectin and NH3+ groups of gelatin, which was confirmed by FTIR spectroscopy. The addition of gelatin to pectin-based gel formulations resulted in a decrease in gel strength, whereas increasing gelatin concentration enhanced this effect. The microparticle gel strength increased in proportion to the increase in the pectin concentration. The DSC and TGA analyzes showed that pectin-gelatin gels had the higher thermal stability than individual pectins. The gel strength, Ca2+ content and thermal stability of the microparticles based on gelatin and SVC pectin with a lower degree of methylesterification (DM) (14.8 %) were higher compared to that of microparticles based on gelatin and AU pectin with a higher DM (40 %). An increase in the SVC concentration, Ca2+ content and gel strength of SVC-gelatin microparticles led to a decrease in the swelling degree in simulated gastrointestinal fluids. The addition of 0.5 % gelatin to gels based on AU pectin resulted in increased stability of the microparticles in gastrointestinal fluids, while the microparticles from AU without gelatin were destroyed.

Effective biosorption of Al ions from drinking water by lignocellulosic biomass rice straw

High concentration of aluminum (Al) in drinking water is a major intake source of it and can result in serious diseases. Rice straw (RS) as lignocellulosic biomasses has great potential to peak up metal ions from aqueous environment, however, feasibility of Al3+ removal by RS has not been investigated yet. The present study aimed to evaluate the capacity of RS as a novel biosorbent for Al3+ from drinking water. Biosorption characteristics of RS were surveyed through several biological and physiochemical techniques. Additionally, isotherm, kinetic and thermodynamic studies were evaluated using various common models. BET profiles revealed the presence of textural mesoporosity on heterogeneous surface, which leading to improve the biosorption capacity. SEM-EDS analysis confirmed the morphological changes as irregularly particles of Al3+ on external surface via physical mechanism. The results of bioassays and FTIR analysis showed carboxylic and hydroxyl groups in lignin and pectin as the main Al3+ binding site. The batch experimental results showed the maximum biosorption capacity of 283.09 mg/g and removal efficiency of 94.86% for Al3+ at biosorbent dosage of 0.05 g/100 mL, contact time of 50 min, pH 7.5, and temperature of 30 °C. The Freundlich model has the best match and suggests the biosorption process as a multi-layer. According to the results of free activation energy, biosorption process was also physical. As thermodynamic result, the biosorption behavior was found spontaneous and endothermic. Consequently, results showed RS as an economical biosorbent for reducing Al3+ of drinking water. Meanwhile, it can be considered as one of the most appropriate methods for management of rice paddies waste.

Effect of Temperature and Extraction Time on the Yield, Water Content, and Methoxyl of Coconut Fiber Pectin

This research aims to see the effect of temperature and extraction time on water content, yield and methoxyl content of coconut fiber pectin. This research was carried out experimentally factoril in Design Random Complete, which consists two treatment that is temperature extraction and extraction time with three repetitions. The results of this research show that treatment temperature extraction very influence yield pectin, rate water and methoxyl pectin while the extraction time affects the water content of the pectin. At a temperature of 70 O C and long extraction 60 minutes obtained the highest average yield of pectin, namely 4.31%, while the average the lowest pectin yield was obtained from treatment with an extraction temperature of 90 ° C and an extraction time of 90 minute. Average rate methoxyl highest obtained from treatment temperature 70 O C and long extraction 30 minute, whereas average percent rate methoxyl Lowest obtained from treatment with an extraction temperature of 90 O C and an extraction time of 90 minutes, namely 8.03% and 7.61% respectively. From the results obtained, it was concluded that the pectin obtained was classified as deep pectin group with high methoxyl content, namely >7%. Average percent of pectin content The lowest was 90 O C and the extraction time was 90 minutes, namely 10.19%, while the highest obtained from treatment with an extraction temperature of 70 O C and an extraction time of 30 minutes. From the results of the analysis this water content means that the water content of the coconut fiber pectin obtained is deep study this has fulfil condition for water content dry pectin that is 10-14%.

Modulation of pectin on intestinal barrier function via changes in microbial functional potential and bile acid metabolism

Weaning is one of the major factors that cause stress and intestinal infection in infants and in young animals due to an immature intestine and not fully developed immune functions. Pectin (PEC), a prebiotic polysaccharide, has attracted considerable attention in intestinal epithelial signaling and function via modulation of the microbial community. A total of 16 weaned piglets (21-d-old) were randomly assigned into two groups: control group and PEC group. Supplementation of 5% pectin improved intestinal mucosal barrier function by modulating the composition of the bile acid pool in piglets. Specifically, piglets in PEC group had less serum D-lactate content and alkaline phosphatase activity. In the ileum, dietary pectin increased the number of crypt PAS/AB-positive goblet cells and the mRNA expressions of MUC2, ZO-1, and Occludin. Piglets in PEC group displayed a decreased abundance of Enterococcus (2.71 vs. 65.92%), but the abundances of Lactobacillus (30.80 vs. 7.93%), Streptococcus (21.41 vs. 14.81%), and Clostridium_sensu_stricto_1 (28.34 vs. 0.01%) were increased. Elevated concentrations of bile acids especially hyocholic acid species (HCAs) including HCA, HDCA, and THDCA were also observed. Besides, correlation analysis revealed that dietary pectin supplementation may have beneficial effects through stimulation of the crosstalk between gut microbes and bile acid synthesis within the enterohepatic circulation. Thus, dietary pectin supplementation exhibited a further positive effect on the healthy growth and development of weaned piglets. These findings suggest pectin supplementation as the prebiotic is beneficial for gut health and improvement of weaned stress via regulating microbiota and bile acid metabolism.

INTERACTION OF PECTIN WITH THE ANTIBACTERIAL DRUG NITROXOLINE

The process of macromolecular complexation of natural polymer pectin with nitroxoline, which has antibacterial activity, was studied in order to increase the solubility of the drug and, consequently, its therapeutic efficiency. By potentiometric titration it has been shown that in dilute aqueous solutions in a wide range of slightly acidic, neutral, and alkaline pH medium, the electrostatic binding of nitroxoline with pectin occurs. In the most optimal for medical preparations neutral region pH 7 the conversion depth of this reaction was calculated. The depth of conversion of pectin carboxyl groups ɵ1 for various studied ratios P : NOC=10 : 1, 5 : 1, 3 : 1 is 0.052, 0.076, and 0.095, respectively. The corresponding values of the conversion depth for nitroxoline ɵ2 are somewhat larger and amount to 0.52, 0.38, 0.32, respectively, for the studied ratios. That is, the calculation shows that not all reactive carboxyl groups of pectin and amino groups of the medicinal substance participate in electrostatic interaction.
 By the viscometry method it has been established the decrease of the pectin solution viscosity in the presence of nitroxoline. This indicates that electrostatic bonding of the low molecular weight medicinal substance NOC leads to the hydrophobization of the pectin macromolecule.
 Comparative data, obtained by the method of derivatographic analysis, indicate, that the thermal characteristics of the studied complex of nitroxoline with pectin differ from the thermal parameters of the initial components and is thermally more stable. This confirms the formation of the product of chemical interaction - the complex of pectin with NOC.

Synthesis and study of composite materials based on apple pectin and copper cations

The paper presents the results of synthesis the metal-composite materials based on apple pectin and divalent metal cations - Cu2+; determining the degree of esterification and the content of free carboxyl groups of the native pectin by acid-base titration, determining the degree of inclusion of the specified cation in the polysaccharide macromolecule and studying by IR spectroscopy and fungicidal activity of native pectin and copper complexes against Penicillum sp According to the results of titration, it was found that apple pectin has a high degree of esterification (DE = 50.7%) and a low content of carboxyl groups (Kc = 2.79%), which suggests its low gelling activity. It was found that the increase in salt concentration is above 0.005 g-eq/l. leads to a decrease in the proportion of the resulting water-soluble complex. The optimal concentration of CuSO4 5H2O, at which the largest mass of the water-soluble complex is formed, is 0.005 g-eq/l. According to IR spectroscopy, the degree of substitution of sodium cations for copper cations was calculated, which amounted to 18%. It was shown that the native apple pectin does not have fungicidal activity, while the copper complex based on it is able to suppress the growth of the culture already under the action of 10 µl of the substance, and with an increase in volume to 50 µl, an even more active fungicidal activity of the copper complex appears.

Effect of bio-chemical changes due to conventional ageing or chemical soaking on the texture changes of common beans during cooking

To establish the HTC defect development, the cooking kinetics of seeds of ten bean accessions (belonging to seven common bean market classes), fresh and conventionally aged (35 °C, 83% RH, 3 months) were compared to those obtained after soaking in specific salt solutions (in 0.1 M sodium acetate buffer at pH 4.4, 41 °C for 12 h, or 0.01 M CaCl2 at pH 6.2, 25 °C for 16 h and subsequently cooking in CaCl2 solution, or deionised water). The extent of phytate (inositol hexaphosphate, IP6) hydrolysis was evaluated to better understand the role of endogenous Ca2+ in the changes of the bean cooking kinetics. A significant decrease in the IP6 content was observed after conventional ageing and after soaking in a sodium acetate solution suggesting phytate hydrolysis (release of endogenous Ca2+). These changes were accompanied by an increase in the cooking time of the beans. Smaller changes in cooking times after soaking in a sodium acetate solution (compared to conventionally aged beans) was attributed to a lower ionisation level of the COOH groups in pectin (pH 4.4, being close to pKa value of pectin) limiting pectin Ca2+ cross-linking. In beans soaked in a CaCl2 solution, the uptake of exogenous cations increased the cooking times (with no IP6 hydrolysis). The change in cooking time of conventionally aged beans was strongly correlated with the extent of IP6 hydrolysis, although two groups of beans with low or high IP6 hydrolysis were distinguished. Comparable trends were observed when soaking in CaCl2 solution (r = 0.67, p = 0.14 or r = 0.97, p = 0.03 for two groups of beans with softer or harder texture during cooking). Therefore a test based on the Ca2+ sensitivity of the cooking times, implemented through a Ca2+ soaking experiment followed by cooking can be used as an accelerated test to predict susceptibility to HTC defect development during conventional ageing. On the other hand, a sodium acetate soaking experiment can be used to predict IP6 hydrolysis of conventionally aged bean accessions and changes of cooking times for these bean accessions (with exception of yellow bean-KATB1).