Pectin Research Articles

Preparation of branched RG-I-rich pectin from red dragon fruit peel and the characterization of its probiotic properties

Red dragon fruit peel is a pectin-rich fruit waste that is a potential source of prebiotics and whose different sources and structures will influence its prebiotic function. Thus, we compared the effects of three extraction methods on the structure and prebiotic function of red dragon fruit pectin, the results showed that the citric acid extracted pectin produced a high Rhamnogalacturonan-I (RG-I) region (66.59 mol%) and more side-chains of Rhamnogalacturonan-I ((Ara + Gal)/Rha = 1.25), which can promote bacterial proliferation significantly. The side-chains of Rhamnogalacturonan-I may be an important factor in that pectin can promote the proliferation of B. animalis. Our results provide a theoretical basis for the prebiotic application of red dragon fruit peel.

Structural characterization and anti-oxidation activity evaluation of pectin from Lonicera japonica Thunb.

Pectins are nutrient components of plants and are widely used in the food industry. In this study, one major pectin fraction (WLJP-A0.2b) with Mw of 40.6 kDa was purified from Lonicera japonica Thunb. The structural feature and antioxidant activity of it was investigated. Monosaccharide composition, Fourier transform infrared (FT-IR) spectra, enzymatic hydrolysis, and nuclear magnetic resonance (NMR) spectra analysis indicated that WLJP-A0.2b consisted of rhamnogalacturonan I (RG-I), rhamnogalacturonan II (RG-II), and homogalacturonan (HG) domains, with mass ratio of 0.4:1.0:2.1. The RG-I domain contained highly branched α-L-1,5-arabinan, β-D-1,4-galactan and type II arabinogalactan (AG-II) side chains. The HG domain was released in the form of un-esterified and partly methyl-esterified and/or acetyl-esterified oligogalacturonides with degree of polymerization 1–8 after degradation by endo-polygalacturonase. Radical scavenging assays indicated that WLJP-A0.2b exhibited antioxidant activity through the synergistic effects of different pectin domains. Oligogalacturonides, especially de-esterified oligogalacturonides, showed better antioxidant activities than RG-II and RG-I domains. Moreover, de-esterified oligogalacturonides remarkably reduced H2O2-induced reactive oxygen species production in HEK-293T cells. These results provide useful information for screening of natural antioxidants from Lonicera japonica Thunb. and application of pectin in functional food field.

Effect and Mechanism of Pharmaceutical Excipients on Berberine to Alleviate Ulcerative Colitis via Regulating Gut Microbiota.

Background: Various potential effect of drugs on alleviating diseases by regulating intestinal microbiome as well as the pharmaceutical excipients on gut microbiota has been revealed. However, the interaction between them is rarely investigated. Methods: Histological analysis, immunohistochemistry analysis, enzyme-linked immunosorbent assay (ELISA) analysis, RT-qPCR, and 16S rRNA analysis were utilized to explore the effect mechanism of the five excipients including hydroxypropyl methylcellulose (HPMC) F4M, Eudragit (EU) S100, chitosan (CT), pectin (PT), and rheum officinale polysaccharide (DHP) on berberine (BBR) to cure UC. Results: The combined BBR with PT and DHP group exhibited better therapeutic efficacy of UC with significantly increased colon length, and decreased hematoxylin-eosin (H&E) scores than other groups. Furthermore, the expression of tight junction ZO-1 and occludin in colon tissue were upregulated, and claudin-2 was downregulated. Ultimately, the serum content of tumor necrosis (TNF)-α, interleukin (IL)-1β, and IL-6 was decreased. Moreover, the combined BBR with PT significantly promoted the restoration of gut microbiota. The relative abundance of Firmicutes and Lactobacillus was significantly increased by the supplement of PT and DHP, and the relative abundance of Proteobacteria was downregulated. Conclusions: Our study may provide a new perspective that the selection of pharmaceutical excipients could be a crucial factor affecting the drugs’ therapeutic efficiency outcome.

Preparation of shell-core fiber-encapsulated Lactobacillus rhamnosus 1.0320 using coaxial electrospinning

In this study, shell-core fibers were successfully prepared by using Eudragit S100 (ES100) and poly(vinyl alcohol) (PVA)/pectin (PEC) through coaxial electrospinning technology. The electrospun fiber was characterized by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray diffraction (XRD). Thermo-gravimetric analysis (TGA) showed that the coaxial electrospun fiber encapsulated with Lactobacillus rhamnosus 1.0320 (L. rhamnosus) had higher thermal stability than the electrospun fiber prepared by uniaxial electrospinning. L. rhamnosus encapsulated by coaxial electrospun fiber maintained 90.07% and 91.96% survivability in simulated gastric and intestinal fluids. After continuous simulated gastrointestinal fluid treatment, the survival rate of L. rhamnosus encapsulated by coaxial electrospun fiber was 81.40%. The results indicate that shell-core fiber-encapsulated probiotics can improve the tolerance of probiotics to the harsh environment of gastrointestinal tract. The fiber prepared in this study can be applied to the preparation of functional fermented food such as probiotic yogurt fermentation in the future.

Effect of biopolymers and their mixtures with glycine on the formation kinetics of methane hydrates

In oil and gas industry formation of gas hydrates are a huge nuisance which disturbs the flow assurance. Kinetic Hydrate Inhibitors (KHIs) have been investigated, developed, and applied to retard the hydrate formation and ensure the smooth flow. Among KHIs, glycine and biodegradable polymers are investigated as potent gas hydrate inhibitors. In this work the kinetic performance of synergic materials which are the combination of biopolymers and amino acid is evaluated for inhibiting methane hydrates. Where, 0.2 wt% of biopolymers including Pectin (PC), Sodium-Carboxymethyl cellulose (Na-CMC), Tapioca starch (TS) and Xanthan gum (XG)) are mixed with 5 wt% of glycine (G). The investigation is conducted by isochoric constant cooling method on sapphire reactor at 9.5 MPa and temperatures of 274 K and 277 K. Three main factors i.e., induction time, hydrate formation rate and mole consumption of methane are observed to determine the formation kinetics of methane hydrates. In addition, percentage relative inhibition strength (%RIS) of biopolymer + glycine mixtures are compared with literature. Results revealed that, G + XG delayed the induction time to 47 min at 274 K and reduced the hydrate formation rates at 277 K. As for mole consumption, G + XG and G + PC consumed the least amount of gas.

Natural melanin nanoparticle-based photothermal film for edible antibacterial food packaging

Although nanocomposite films had shown excellent potential in antibacterial food packaging, their potential harmful impact limits their further application in reality. Therefore, exploring a Generally Recognized As Safe (GRAS) nanomaterial that has antibacterial ability is the pioneer for the fabrication of a real edible nanocomposite-based antibacterial packaging film. Herein, for the first time by using the natural nanostructure extracted from cuttlefish ink, an edible antibacterial food packaging with high safety were constructed. The natural melanin nanoparticles (NMPs) in cuttlefish ink have good photothermal conversion ability. As such, by incorporating with natural pectin (PC) film and with near infrared (NIR) irradiation triggering, the results show that PC/NMPs films perform high-efficiency and short-term bactericidal activity against foodborne pathogenic bacteria, including thermotolerant Listeria monocytogenes. The sterilization rate could reach more than 90 % within only 5 min. Also, this nanocomposite film showed better mechanical properties, thermal stability and barrier properties than the neat pectin film. Antibacterial test on food sample also proved the good antibacterial ability of the PC/NMPs films. Therefore, exploring GRAS natural functional nanocomposite film is expected to be the effective way to promote edible nano-antibacterial packaging.

Extraction and characterization of a pectin from sea buckthorn peel.

Sea buckthorn peel is the by-product of the sea buckthorn processing, which contains many bioactive compounds. In this paper, sea buckthorn high methoxyl pectin (SBHMP) was obtained, with a yield of 8% and a light-colored. The SBHMP was a high methoxyl with a degree of esterification of 57.75% and uronic acid content of 65.35%. The structural and morphological characterization of SBHMP were analyzed by high-performance liquid chromatography, Fourier-transform infrared spectroscopy, and scanning electron microscopy. Results showed that SBHMP presented a sheet and layered stacked morphological, and was mainly composed of galacturonic acid, arabinose, galactose, rhamnose, and mannose, which indicated that SBHMP mainly consisted of homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) type pectin polysaccharides. In addition, SBHMP also presented significant gel, thickening, and emulsifying properties. The results exhibited that SBHMP could form jelly-like gels under acid and high sucrose conditions, presenting a shear-thinning behavior and increasing apparent viscosity with the enhancement of pectin and sucrose contents. Besides, SBHMP could form oil-in-water emulsions with pectin concentrations of 1.0–3.0%. When the SBHMP concentrations were 2.0 and 3.0%, the emulsions were stable during 7 days of storage. Findings in this paper demonstrated the potential of SBHMP to be a food thickener and emulsifier and support the in-depth utilization of sea buckthorn by-products.

Acceleration effect of galacturonic acid on acrylamide generation: evidence in model reaction systems.

Acrylamide (AA) is a potential carcinogen formed in food rich in carbohydrate during heating. Recently, AA has been found in several fruit products, such as prune juice, sugarcane molasses and canned black olives. This study focused on the role of galacturonic acid (GalA), the main acid hydrolysis product of fruit pectin, in AA formation in three model systems - asparagine (Asn)/glucose (Glc), Asn/GalA, and Asn/Glc/GalA - during heating under different pH values (pH3.8-7.8), Glc concentration (0-0.1mol L-1 ), molar ratio of substrates (Asn/Glc=1:1, 0.025-0.5mol L-1 ) and temperature (120-180 °C) for 30 min, respectively. The results suggested that the addition of 0.1mol L-1 GalA strongly accelerated AA formation in a manner dependent on pH value and temperature (P < 0.05). AA concentration under different Glc concentration and molar ratio of substrates suggested that GalA was more reactive than Glc when reacted with Asn. Furthermore, the Amadori rearrangement product/Schiff base/oxazolidine-5-one were identified as the intermediates formed in the Asn/GalA model system using ultra-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry. The results suggested that Maillard reaction between Asn and GalA might contribute to AA formation. This study is significant in elucidating the contribution of interaction between components for AA formation in fruit products. © 2022 Society of Chemical Industry.

Basic helix-loop-helix (bHLH) transcription factor MdbHLH3 negatively affects the storage performance of postharvest apple fruit

The storage period of fleshy fruits greatly affects their quality and selection, and is largely controlled by genetic factors. Therefore, it is imperative to elucidate how genetic factors affect fruit ripening and its storage. Here, we evaluated the postharvest storage properties of the basic helix-loop-helix (bHLH) transcription factor MdbHLH3-overexpressing transgenic Royal gala apple fruits. During storage, the contents of starch, malic acid, fructose, glucose, and sucrose in fruits of three MdbHLH3 transgenic lines were always higher than those of the wild-type (WT) control. Interestingly, the sugar-acid ratio also showed the same trend during fruit storage. Additionally, the fruit firmness decreased with increasing storage time, and the contents of cell wall components such as water-soluble pectin and cellulose in transgenic fruits were higher than those in control fruits, while the firmness of transgenic fruits was lower than that in WT control fruits. Though the ethylene release rate in both showed the same trend (firstly increasing, then decreasing, and finally peaking) in 90-day stored fruits, transgenic apples had higher ethylene levels than the WT control throughout storage. Furthermore, the activities of membrane peroxidase, antioxidant enzymes, and fruit ripening enzymes in all transgenic fruits were significantly higher than those in the WT control. Thus, our findings show how MdbHLH3 negatively regulates and reduces apple storage time. This may prove useful for not only developing biotechnological strategies, but also support traditional breeding programs, to help improve the storage time of fleshy fruits.

Characterization of a new food packaging material based on fish by-product proteins and passion fruit pectin

The development of biodegradable bioplastics based on renewable raw materials has emerged as an innovative option to minimize the adverse effects of improper disposal of petrochemical packaging in the environment. This study aimed to optimize the conditions for bioplastic production from proteins of the cutting by-product of Serra Spanish Mackerel (Scomberomorus brasiliensis) and pectin of the yellow passion fruit (Passiflora edulis Flavicarpa), evaluating the physical, mechanical and thermal characteristics of the optimized bioplastic. According to the results, the optimal conditions for obtaining the bioplastic were 5.0% protein concentrate and 3.0% pectin. The optimized film was homogeneous, strong, flexible, and biodegradable, with low solubility and water vapor permeability, indicating that the protein and pectin biopolymers had good interaction and could produce bioplastics. Therefore, there was a satisfactory interaction between the incorporated biopolymers, indicating their application in the food industry and thus causing a reduction in the production of industrial by-products.

Physicochemical and functional properties of Lycium ruthenicum pectin by different extraction methods.

Three different extraction methods were used to extract high-temperature water-extracted pectin (HWp), high-temperature acid-extracted pectin (HAp), and high-temperature alkali-extracted pectin (HALp) from Lycium ruthenicum. The physicochemical properties, structure, and functional properties of three different pectins were studied. The results showed that HWp and HALp can extract rhamnogalacturonan-I (RG-I) from L. ruthenicum better. Through structural feature analysis, HWp and HALp have a branched structure, and HWp has a higher degree of esterification than HAp and HALp. Zeta potential results show that HWp solution is more stable. The thermal analysis results show that the thermal stability is HALp > HAp > HWp. HWp has the highest viscosity. The inhibitory activity results showed that HWp, HAp, and HALp have a certain inhibitory effect on α-glucosidase activity. This study shows the effects of different extraction methods on the properties of L. ruthenicum pectin and aims to provide a theoretical basis for the pharmaceutical and food industries to choose more suitable pectin extraction methods.

Gamma irradiation synthesis of pectin- based biohydrogels for removal of lead cations from simulated solutions

Bio-based hydrogels (denoted as PC-PAAc/GA) comprised of Pectin (PC) and polyacrylic acid (PAAc) reinforced with different ratios of gallic acid (GA) were prepared by gamma radiation at irradiation dose 20 kGy. The prepared hydrogels were investigated by different analytical tools. The swelling performance was studied versus time, pH of the medium and gallic acid content. The experimental data depicted that the swelling increases with pH of medium until the equilibrium of swelling after 350 min. The maximum swelling was attained at pH10 for both PC-PAAc and PC-PAA/GA1.5. Also, the data reveal that the incorporation of GA in the hydrogel matrix enhanced the swelling performance of the hydrogel up to an optimum value of GA, i.e. PC-PAA/GA1.5. Further increase in GA concentration leads to formation of a highly crosslinked structure with reduced swelling. The results demonstrated that the prepared hydrogels displayed excellent antibacterial activity against gram + ve bacteria (E.coli) and gram-ve bacteria (S.aureus). This potent antimicrobial activity is mainly originated from GA which was proved as a strong antibacterial agent. Moreover, the removal performance of the investigated hydrogels was verified towards Pb+2 cation as one of the most poisonous heavy metals. The data revealed that the maximum removal percentage of Pb (II) was attained by PC-PAAc/GA1.5 hydrogel (90 mg g−1). The correlation coefficients of the Langmuir model are too higher than that of the Freundlich model that assumed the adsorption of lead cations is mainly a chemical process.

Comparative study of HG-type low-ester hawthorn pectin as a promising material for the preparation of hydrogel

Homogalacturonan (HG)-type pectin has been considered suitable for the formation of hydrogel, but it is unknown whether the less side chain will limit the properties of hydrogel. The current study successfully obtained low methoxyl HG-type hawthorn pectin (LMHP) from hawthorn by sequential hot water extraction and alkaline de-esterification. The proportion of HG domain, the proportion of rhamnogalacturonan-I (RG-I) domain, molecular weight, and particle size of LMHP were 81.13 %, 4.04 %, 348.43 kDa, and 1386.92 nm, respectively. Compared with commercial citrus pectin (CP), LMHP was more suitable for the preparation of hydrogel. The hydrogel with the densest network structure and relatively stable performance in digestion simulation environment can be obtained as the concentration of LMHP increases to 2.5 %, which is lower than the consumption of commercial citrus pectin. Overall, these findings highlight the potential of hawthorn pectin as a novel hydrogel raw material.

Purification and fine structural analysis of pectic polysacchrides from Osmunda japonica Thunb

Osmunda japonica Thunb, as a traditional edible wild herb in China, has a wide range of pharmacological effects. In this study, two pectic polysaccharides, WOJP-A-b and WOJP-A-c, were obtained from O. japonica stalks by water extraction and alcohol precipitation method, and their fine structures were investigated. Monosaccharide composition and molecular weight analyses showed that WOJP-A-b (10.6 kDa) was mainly composed of galacturonic acid (GalA), with less galactose (Gal) and arabinose (Ara) (molar ratio = 68.3: 12.5: 9.0), while WOJP-A-c (6.6 kDa) was primarily composed of GalA, Gal, Ara, and rhamnose (Rha) residues in a molar ratio of 39.4: 41.2: 11.8: 6.8. The results indicated that WOJP-A-b consisted of esterified homogalacturonan (HG) domains, while WOJP-A-c contained HG domains, as well as 1,4-β-galactan and 1,5-α-arabinan, which might be linked covalently to the minor rhamnogalacturonan I (RG-I) domains. The results of this study will provide the basis for structure-activity relationship studies of O. japonica polysaccharides and development of natural functional foods and pharmaceuticals.

Pectin supplementation ameliorates intestinal epithelial barrier function damage by modulating intestinal microbiota in lipopolysaccharide-challenged piglets

During weaning, infants and young animals are susceptible to severe enteric infections, thus inducing intestinal microbiota dysbiosis, intestinal inflammation, and impaired intestinal barrier function. Pectin (PEC), a prebiotic polysaccharide, enhances intestinal health with the potential for a therapeutic effect on intestinal diseases. One 21-d study was conducted to investigate the protective effect of pectin against intestinal injury induced by intraperitoneal injection of Escherichia coli lipopolysaccharide (LPS) in a piglet model. A total of 24 piglets (6.77±0.92 kg BW; Duroc × Landrace × Large White; barrows; 21 d of age) were randomly assigned into three groups: control group, LPS-challenged group, and PEC + LPS group. Piglets were administrated with LPS or saline on d14 and d21 of the experiment. All piglets were slaughtered and intestinal samples were collected after 3 h administration on d21. Pectin supplementation ameliorated the LPS-induced inflammation response and damage to the ileal morphology. Meanwhile, pectin also improved intestinal mucin barrier function, increased the mRNA expression of MUC2, and improved intestinal mucus glycosylation. LPS challenge reduced the diversity of intestinal microbiota and enriched the relative abundance of Helicobacter. Pectin restored alpha diversity and improved the structure of the gut microbiota by enriching anti-inflammatory bacteria and short-chain fatty acids (SCFAs)-producing bacteria, and increased the concentrations of acetate. In addition, Spearman rank correlation analysis also revealed the potential relationship between intestinal microbiota and intestinal morphology, intestinal inflammation, and intestinal glycosylation in piglets. Taken together, these results indicate that pectin enhances intestinal integrity and barrier function by altering intestinal microbiota composition and their metabolites, which subsequently alleviates intestinal injury and finally improves the growth performance of piglets.

Conformational Properties of Flaxseed Rhamnogalacturonan-I and Correlation between Primary Structure and Conformation.

The pectic polysaccharides extracted from flaxseed (Linum usitatissiumum L.) mucilage and kernel were characterized as rhamnogalacturonan-I (RG-I). In this study, the conformational characteristics of RG-I fractions from flaxseed mucilage and kernel were investigated, using a Brookhaven multi-angle light scattering instrument (batch mode) and a high-performance size exclusion chromatography (HPSEC) system coupled with Viscotek tetra-detectors (flow mode). The Mw of flaxseed mucilage RG-I (FM-R) was 285 kDa, and the structure-sensitive parameter (ρ) value of FM-R was calculated as 1.3, suggesting that the FM-R molecule had a star-like conformation. The Mw of flaxseed kernel RG-I (FK-R) was 550 kDa, and the structure-sensitive parameter (ρ) values ranged from 0.90 to 1.21, suggesting a sphere to star-like conformation with relatively higher segment density. The correlation between the primary structure and conformation of RG-I was further discussed to better understand the structure–function relationship, which helps the scale-up applications of pectins in food, pharmaceutical, or cosmetic industries.

Anti-melanogenesis effect from Wampee fruit pectin via α-MSH/TRY pathway in A375 cells

BackgroundPolysaccharides from wampee have been reported to process various biological activities, while the relationship between structure and bioactivities has been barely addressed. Pectin, an abundant water-soluble polysaccharide in wampee, showed significant antioxidant activity, which was associated with the anti-melanogenic activity. Therefore, this study investigated the physicochemical characteristics and the anti-melanogenesis effect of pectin extracted from wampee fruit in A375 cells.MethodsThe physicochemical characterization of pectin from wampee fruit was investigated by gel chromatography (GCP), FT-IR spectroscopy, and NMR spectroscopy methods. The anti-melanogenesis effects and mechanism were evaluated by mushroom tyrosine enzyme and human melanin cell model in vitro.ResultsThe results showed that a molecular weight of 5.271 × 105 Da wampee fruit pectin (WFP) were mainly composed of mannose (Man), ribose (Rib), rhamnose (Rha), glucuronic acid (Glc A), glucose (Glc), galacturonic acid (Gal A), galactose (Gal), and arabinose (Ara), which linked with →4)-β-D-Galp-(1 → units. The current study revealed that WFP could significantly suppress mushroom TRY activity in vitro. Furtherly, WFP significantly reduced intracellular and extracellular melanin formation in A375 melanoma cells depending on the presence of alpha-melanocyte stimulating hormone (α-MSH). TRY activity was only inhibited in α-MSH treated A375 cells. Western blot analysis demonstrated that WFP reverse α-MSH induced melanogenesis in A375 melanoma cells, including in down-regulated TRY, TYRP-1, TYRP-2, MITF and CREB expressions.ConclusionThese results indicated that WFP could inhibit α-MSH induced melanogenesis in A375 melanoma cells via α-MSH/TRY pathway. In conclusion, these data provided a new perspective to annotate WFP anti-melanogenesis activity mechanism.

Acidic electrolyzed water improves the postharvest quality of jujube fruit by regulating antioxidant activity and cell wall metabolism

Disease development of ‘Lingwu Long’ jujube fruit treated with acidic electrolyzed water (AEW) at 4 ± 1℃ for storing 30 d was evaluated by the reactive oxygen species (ROS) metabolism, phenylpropanoid metabolism, and cell wall metabolism. Compared to the control, jujube fruit treated with AEW had a lower disease index. At the end of storage, AEW treatment maintained lower malondialdehyde (2.1 μmol kg−1) and superoxide anion generation rate (41.5 nmol g−1 min−1) compared to the control, while enhancing catalase (127.2 U g−1) and superoxide dismutase activities (244.2 U g−1). AEW treatment increased 1,1-diphenyl-2-picrylhydrazyl scavenging ability and hydrogen peroxide. The higher contents of ascorbic acid and glutathione were related to higher activities of ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase, and dehydroascorbate reductase in AEW-treated jujube fruit. Moreover, the highest activities of phenylalanine ammonia lyase (21.1 U g−1), cinnamate-4-hydroxylase (304.2 U g−1), and 4-coumarate-CoA ligase (6.4 U g−1) and contents of total phenolics (5.3 g GAE kg−1) and total flavonoids (0.3 mg RE g−1) were observed in AEW-treated fruit compared to the control. Higher firmness, Na2CO3-soluble pectin, cellulose, and hemicellulose and lower water-soluble pectin in AEW-treated fruit were due to lower activities of polygalacturonase, pectinate lyases, β-galactosidase, and cellulase. As a result, AEW could be used for decreasing decay occurrence and maintaining storage quality of jujube fruit.

Fouling alleviation and enhanced salt rejection in NF membranes via incorporation of 5-amino-1-phenyl-3-(thiophen-2-yl)-1H-pyrazole-4‑carbonitrile functionalized pectin in PES matrix

In the current study, the facile method of 5-amino-1-phenyl-3-(thiophen-2-yl)-1H-pyrazole-4‑carbonitrile (pyrazole compound) functionalization was introduced to synthesize the new kind of pectin-based material with high functionality and hydrophilicity. The obtained pyrazole compound/pectin (PCPT) hybrid was characterized by SEM, XRD, FTIR, and EDX. Consequently, it was incorporated into the polyethersulfone (PES) nanofiltration (NF) membrane at different loadings. The pectin (PT) composite membranes (PT-0.3 and PT-0.5) were also prepared to further prove the influence of the used PT functionalization method on membrane performance. The surface properties and filtration performance of the composite membranes were studied. All composite membranes showed higher pure water flux compared to the bare membrane (PT-0) and in the best case, the pure water flux value of 43.22 L/m2h was obtained for the 0.3 wt% PCPT composite membrane (PCPT-0.3). PCPT-0.3 showed the highest mean pore size, porosity, surface hydrophilicity, smoothness, and negative charge among all prepared composite membranes. After incorporation of PCPT hybrid, the salt rejection was considerably enhanced with the sequence of Na2SO4 > NaCl, verifying the typical NF behavior of the membranes. For PCPT-0.3, the rejection of direct red 16 (DR16) and crystal violet (CV) was 99.82 and 98.24%, and the corresponding permeate flux was 40.2 and 40.1 L/m2h, respectively. Pb2+, Cu2+, and Cd2+ rejections were measured 31.00, 32.00, and 32.50% for PT-0, whereas they were 98.09, 98.32, and 98.63% PCPT-0.3, respectively. Moreover, PCPT-0.3 exhibited excellent antifouling properties, nominating the PCPT hybrid as a privileged membrane modifier for the treatment of water/wastewater.

Rhamnogalacturonan Endolyase Family 4 Enzymes: An Update on Their Importance in the Fruit Ripening Process

Fruit ripening is a process that produces fruit with top sensory qualities that are ideal for consumption. For the plant, the final objective is seed dispersal. One of the fruit characteristics observed by consumers is texture, which is related to the ripening and softening of the fruit. Controlled and orchestrated events occur to regulate the expression of genes involved in disassembling and solubilizing the cell wall. Studies have shown that changes in pectins are closely related to the loss of firmness and fruit softening. For this reason, studying the mechanisms and enzymes that act on pectins could help to elucidate the molecular events that occur in the fruit. This paper provides a review of the enzyme rhamnogalacturonan endolyase (RGL; EC 4.2.2.23), which is responsible for cleavage of the pectin rhamnogalacturonan I (RGL-I) between rhamnose (Rha) and galacturonic acid (GalA) through the mechanism of β-elimination during fruit ripening. RGL promotes the loosening and weakening of the cell wall and exposes the backbone of the polysaccharide to the action of other enzymes. Investigations into RGL and its relationship with fruit ripening have reliably demonstrated that this enzyme has an important role in this process.