Search Results (36)

The agro-industrial sector generates large volumes of fruit waste each year, leading to environmental concerns and sustainability challenges. In this study, we evaluate the potential of fruit residues—apple, pear, blueberry, tomato, papaya, and a mixed fruit juice blend—as alternative sources of high-value polysaccharides, including pectins, hemicelluloses, and cellulose. Additionally, white strawberry, included as a reference from fresh fruit rather than agro-industrial waste, was analyzed to expand the comparative framework. These biopolymers, naturally derived from the plant cell wall, are renewable and biodegradable, and they possess physicochemical properties suitable for applications in food, pharmaceutical, cosmetic, textile, and bioenergy industries. Using a combination of cell wall fractionation, biochemical characterization, and immunodetection of specific structural domains, we identified significant variability in polysaccharide composition and structure among the samples. Blueberry, pear, and apple residues showed high levels of rhamnogalacturonan-I (RG-I) with extensive branching, while variations in rhamnogalacturonan-II (RG-II) dimerization and the degree of methylesterification of homogalacturonan were also observed. These structural differences are key to determining the gelling properties and functional potential of pectins. In the hemicellulose fractions, xylans and xyloglucans with distinct substitution patterns were especially abundant in apple and pear waste. Our findings demonstrate that fruit processing waste holds significant promise as a sustainable source of structurally diverse polysaccharides. These results support the reintegration of agro-industrial residues into production chains and emphasize the need for environmentally friendly extraction methods to enable industrial recovery and application. Overall, this study contributes to advancing a circular bioeconomy by transforming underutilized plant waste into valuable functional materials. Full article

Background: Pectic polysaccharides exhibit therapeutic potential against intestinal inflammation. However, the influence of structural variations on their efficacy remains largely unexplored. Methods: This study investigated the structural and anti-inflammatory relationships of okra pectin (OP), citrus pectin (CP), apple pectin (AP), and hawthorn pectin (HP). Based on FT-IR spectra, CP was identified as a high-methoxyl pectin, with a degree of methyl esterification (DM) of 72.07 ± 3.86%. OP, AP, and HP were low-methoxyl pectins with the following DM values: 19.34 ± 3.04%, 32.11 ± 1.71%, and 38.67 ± 2.75%, respectively. Results: Monosaccharide composition analysis revealed that OP exhibited the highest abundance of RG-I regions among all the samples. Homogalacturonan (HG) was the predominant structural region in AP and HP, while CP contained both of the aforementioned structural regions. Our findings demonstrated that OP and CP significantly ameliorated dextran sulfate sodium (DSS)-induced colitis in the wild-type Drosophila melanogaster strain w¹¹¹⁸, as evidenced by improved intestinal morphology, reinforced intestinal barrier function, and enhanced locomotor and metabolic activity. These effects were mediated by the inhibition of JAK/STAT signaling and the activation of the Nrf2/Keap1 pathway. Notably, reducing the molecular weight of CP to 18.18 kDa significantly enhanced its therapeutic efficacy, whereas a reduction in OP molecular weight to 119.12 kDa extended its median lifespan. Conclusions: These findings first suggest that abundant RG-I structures and low molecular weight endowed pectins with significant anti-inflammatory activity. Full article

The Cocoa Pod Husk (CPH) accounts for 67–76% of the total cocoa fruit weight, making it its main agro-industrial waste of cocoa production. A valorization of this waste is possible through the extraction of pectin. In this study, pectin was extracted from CPH powder by acid hydrolysis using citric acid and sulfuric acid. Fourier transform infrared spectroscopy (FT-IR) was employed as a qualitative and quantitative characterization technique. The FT-IR of the pectin samples showed the bands visible at 1732 and 1626 cm⁻¹ corresponding to the esterified and free carboxylic groups, respectively. These bands can be differentiated according to their degree of methyl esterification (DE) by analyzing the area under the curve. The extracted pectin showed no significant difference in yields (p ≤ 0.05) between the two acids; however, significant differences (p ≤ 0.05) were observed in DE and methoxylation percentage (MeO). According to the FT-IR results, pectin extracted with citric acid presented a lower DE (7.43%) and MeO (1.12%) compared to pectin extracted with sulfuric acid, which showed a DE of 18.15% and a 2.96% MeO. Pectin with a DE below 50% is classified as low-methylated, making it unsuitable for the food industry. However, these create a raw material that has a potential use in the pharmaceutical and bioenergy industries. Full article

The effect of different cell wall degrading enzymes, cellulase (C) and hemicellulase (HC), during the enzyme-assisted extraction (EAE) of pectin from carrot pomace was investigated. The EAE with C and a heat treatment resulted in a pectin yield, purity, and molecular structure comparable to an acid extraction (AE), except for a slightly lower molar mass and a slightly higher degree of methylesterification. The addition of HC had a negligible influence on the pectin yield and structure and mainly resulted in more hemicellulose co-extraction. Overall, the AE still resulted in the highest pectin yield, but, despite the much milder extraction conditions, the optimal EAE process resulted in 80% of the pectin yield of the AE. Additionally, this study investigated an EAE with C in combination with an AE, and both combination treatments, i.e., EAE as pretreatment or as an additional treatment, resulted in a significant increase in the pectin yield (up to 72%), while minor structural differences were observed in the extracted pectin. Overall, it can be concluded that the EAE process can be used as a more environmentally friendly alternative for the AE or that EAE can be used in combination with an AE to improve the efficiency of the extraction process. Full article

Cell walls play essential roles in cell recognition, tissue adhesion, and wound response. In particular, pectins as cell-adhesive agents are expected to play a key role in the early stages of grafting. To test this premise, this study focused on examining the dynamics of the accumulation and degree of methyl-esterification of pectic polysaccharides at the graft junctions using tomato autografts as an experimental model. Monosaccharide analysis showed a marked increase in homogalacturonan from 25% to 32 or 34% at the junction zones early after grafting. In addition, a decrease in the degree of homogalacturonan methyl-esterification up to 38% in the scion and 64% in the rootstock was observed in the first few days after grafting, accompanied by an increase in pectin methyl-esterase activity of up to 20–30% in the tissues surrounding the graft junction. These results shed light on the role of homogalacturonan in grafting and reinforce the key function of pectin as one of the most relevant cell wall components during the grafting process. Full article

Steam explosion (STEX) of peel from commercially juice-extracted oranges was used to convert peel pectin into pectic oligosaccharides (POSs). Surprisingly uniform populations, based on the polydispersity index (PDI; weight-average molecular weight (M_w)/number-average molecular weight (M_n)) of POSs, were obtained from the Hamlin and Valencia varieties of Citrus sinensis. The POSs from Hamlin and Valencia peel had PDI values of (1.23 ± 0.01, 1.24 ± 0.1), respectively. The M_w values for these samples were 14.9 ± 0.2 kDa for Hamlin, and 14.5 ± 0.1 kDa for Valencia, respectively. The degree of methyl-esterification (DM) was 69.64 ± 3.18 for Hamlin and 65.51 ± 1.61 for Valencia. The composition of the recovered POSs was dominated by galacturonic acid, ranging from 89.1% to 99.6% of the major pectic sugars. Only the Hamlin sample had a meaningful amount of rhamnose present, indicating the presence of an RG I domain. Even so, the Hamlin sample’s degree of branching (DBr) was very low (2.95). Full article

Blackcurrant pomace is a widely available waste stream derived from the industrial production of juice rich in pectin and unextracted polyphenols. Since pectin, an emerging class of gastrointestinal prebiotics, is also a common cosmetic ingredient, the aim of this work was to evaluate blackcurrant pomace as a source of pectin-rich fractions suitable for application in prebiotic cosmetics. Hereby, this raw material was valorised by sequential extraction of acid-soluble (by citric acid, CAP) and Ca-bound (by ammonium oxalate, AOPP) pectic polysaccharides. Both fractions had favourable physicochemical features and a similar degree of methyl-esterification between low- and high-methoxyl pectin (approx. 50%), but CAP had significantly higher galacturonic acid content (72.3%), branching, and purity. Regardless of that, both had very high oil (18.96 mL/g for CAP and 19.32 mL/g for AOPP) and water (9.97 mL/g for CAP and 7.32 mL/g for AOPP)-holding capacities and excellent emulsifying properties, making them promising cosmetic ingredients. The polyphenol content was 10 times higher in CAP, while corresponding antioxidant activity was 3-fold higher. Finally, the influence of varying CAP and AOPP concentrations on common skin pathogen, Staphylococcus aureus, and beneficial skin bacteria, Staphylococcus epidermidis, was examined. The results show significant prebiotic potential of two pectic fractions since they were capable of selectively stimulating S. epidermidis, while S. aureus growth was inhibited, whereas CAP demonstrated a particularly high capacity of up to 2.2, even with methicillin-resistant S. aureus. Full article

Phelipanche ramosa is a root parasitic plant fully dependent on host plants for nutrition and development. Upon germination, the parasitic seedling develops inside the infected roots a specific organ, the haustorium, thanks to the cell wall-degrading enzymes of haustorial intrusive cells, and induces modifications in the host’s cell walls. The model plant Arabidopsis thaliana is susceptible to P. ramosa; thus, mutants in cell wall metabolism, particularly those involved in pectin remodeling, like Atpme3-1, are of interest in studying the involvement of cell wall-degrading enzymes in the establishment of plant–plant interactions. Host–parasite co-cultures in mini-rhizotron systems revealed that parasite attachments are twice as numerous and tubercle growth is quicker on Atpme3-1 roots than on WT roots. Compared to WT, the increased susceptibility in AtPME3-1 is associated with reduced PME activity in the roots and a lower degree of pectin methylesterification at the host–parasite interface, as detected immunohistochemically in infected roots. In addition, both WT and Atpme3-1 roots responded to infestation by modulating the expression of PAE- and PME-encoding genes, as well as related global enzyme activities in the roots before and after parasite attachment. However, these modulations differed between WT and Atpme3-1, which may contribute to different pectin remodeling in the roots and contrasting susceptibility to P. ramosa. With this integrative study, we aim to define a model of cell wall response to this specific biotic stress and indicate, for the first time, the role of PME3 in this parasitic plant–plant interaction. Full article

Enhancing stalk strength is a crucial strategy to reduce lodging. We identified a maize inbred line, QY1, with superior stalk mechanical strength. Comprehensive analyses of the microstructure, cell wall composition, and transcriptome of QY1 were performed to elucidate the underlying factors contributing to its increased strength. Notably, both the vascular bundle area and the thickness of the sclerenchyma cell walls in QY1 were significantly increased. Furthermore, analyses of cell wall components revealed a significant increase in cellulose content and a notable reduction in lignin content. RNA sequencing (RNA-seq) revealed changes in the expression of numerous genes involved in cell wall synthesis and modification, especially those encoding pectin methylesterase (PME). Variations in PME activity and the degree of methylesterification were noted. Additionally, glycolytic efficiency in QY1 was significantly enhanced. These findings indicate that QY1 could be a valuable resource for the development of maize varieties with enhanced stalk mechanical strength and for biofuel production. Full article

The pectin methyl esterase gene from Populus trichocarpa (PtPME) was successfully cloned through PCR amplification and subsequently inserted into the expressing vector pMAL-c5e for successful expression in Escherichia coli BL21 (DE3). Initially, we determined the primary enzymatic properties of PtPME, a pectin methyl esterase derived from Populus trichocarpa. Notably, this enzyme exhibits a higher affinity towards citrus pectin, with an esterification degree exceeding 60%. Furthermore, this enzyme’s optimal reaction temperature and pH were found to be 30 °C and 8, respectively. Importantly, its exceptional stability under neutral conditions highlights its potential application in the industrial production of low-ester pectin. Full article

The purpose of the present study was to prepare pectin hydrogels with immobilized Lemna minor callus cells and to identify the effect of cell immobilization on the textural, rheological, and swelling properties; loading; and releasing of grape seed extract (GSE) from the hydrogels. Hardness, adhesiveness, elasticity, the strength of linkage, and complex viscosity decreased with increasing cell content in the hydrogels based on pectin with a degree of methyl esterification (DM) of 5.7% (TVC) and during incubation in gastrointestinal fluids. An increase in the rheological properties and fragility of pectin/callus hydrogels based on pectin with a DM of 33.0% (CP) was observed at a cell content of 0.4 g/mL. TVC-based pectin/callus beads increased their swelling in gastrointestinal fluids as cell content increased. TVC-based beads released GSE very slowly into simulated gastric and intestinal fluids, indicating controlled release. The GSE release rate in colonic fluid decreased with increasing cell content, which was associated with the accumulation of GSE in cells. CP-based beads released GSE completely in the intestinal fluid due to weak textural characteristics and rapid degradation within 10 min. Pectin/callus hydrogels have the ability to preserve GSE for a long time and may have great potential for the development of proanthocyanidin delivery systems due to their novel beneficial physicochemical and textural properties. Full article

Biochemical changes in the cell wall composition and activity of cell wall-modifying enzymes of five apple cultivars, Royal Gala (Gala), Aurora Golden Gala (Aur), Splendour (Spl), Honeycrisp (HC), and Ambrosia (Amb), collected from the 2016 growing season in the early growth phases, namely 40 and 70 days after full bloom (DAFB), at harvest maturity, and after 20 weeks of storage were investigated in relation to the textural changes at harvest maturity through to 20 weeks of storage. Assessing apple texture with a single-point measurement of firmness using a penetration test to a depth of approximately 8 mm in apples may not be an ideal measurement for assessing apple textural quality. Pectin methyl esterase (PME) activity at early developmental stages may be predictive of textural quality after storage. This work also found that β-D-galactosidase (BGAL) and α-L-arabinofuranosidase (AFAS) activities at early developmental stages may be important factors affecting textural quality after storage. Additionally, the degree of methylesterification (DME) assessed with FTIR on apple flesh material at the early developmental stages was strongly positively correlated (r² ≥ +0.891 to +0.963, p ≤ 0.05) with textural quality after storage, including crispness, indicating that FTIR could serve as a rapid screening tool for textural quality at early developmental stages on minimally processed starting material. Full article

Hydrogels were prepared by Steglich esterification and by crosslinking pre-synthesized poly(sorbitol adipate)-graft-poly(ethylene glycol) mono methyl ether (PSA-g-mPEG) using different-chain-length-based disuccinyl PEG. PSA and PSA-g-mPEG were investigated for polymer degradation as a function of time at different temperatures. PSA-g-mPEG hydrogels were then evaluated for their most crucial properties of swelling that rendered them suitable for many pharmaceutical and biomedical applications. Hydrogels were also examined for their Sol-Gel content in order to investigate the degree of cross-linking. Physical structural parameters of the hydrogels were theoretically estimated using the modified Flory–Rehner theory to obtain approximate values of polymer volume fraction, the molecular weight between two crosslinks, and the mesh size of the hydrogels. X-ray diffraction was conducted to detect the presence or absence of crystalline regions in the hydrogels. PSA-g-mPEG hydrogels were then extensively examined for higher and lower molecular weight solute release through analysis by fluorescence spectroscopy. Finally, the cytotoxicity of the hydrogels was also investigated using a resazurin reduction assay. Experimental results show that PSA-g-mPEG provides an option as a biocompatible polymer to be used for pharmaceutical applications. Full article

Common smut caused by Ustilago maydis is one of the dominant fungal diseases in plants. The resistance mechanism to U. maydis infection involving alterations in the cell wall is poorly studied. In this study, the resistant single segment substitution line (SSSL) R445 and its susceptible recurrent parent line Ye478 of maize were infected with U. maydis, and the changes in cell wall components and structure were studied at 0, 2, 4, 8, and 12 days postinfection. In R445 and Ye478, the contents of cellulose, hemicellulose, pectin, and lignin increased by varying degrees, and pectin methylesterase (PME) activity increased. The changes in hemicellulose and pectin in the cell wall after U. maydis infection were analyzed via immunolabeling using monoclonal antibodies against hemicellulsic xylans and high/low-methylated pectin. U. maydis infection altered methyl esterification of pectin, and the degree of methyl esterification was correlated with the resistance of maize to U. maydis. Furthermore, the relationship between methyl esterification of pectin and host resistance was validated using 15 maize inbred lines with different resistance levels. The results revealed that cell wall components, particularly pectin, were important factors affecting the colonization and propagation of U. maydis in maize, and methyl esterification of pectin played a role in the resistance of maize to U. maydis infection. Full article

Food by-products, as sources of high-value compounds, have shown great promise for formulating novel food packaging and edible films for food preservation. This work focused on extracting pectin from lemon, pomelo, and pitaya peels using an ethanol precipitation method. The degree of esterification and the monosaccharide composition of the extracted pectin were determined, and the antioxidant activity of the pectin was assessed. Subsequently, pectin-based films were prepared using the casting method, employing pectin from various sources. These films’ physical and mechanical properties (tensile strength and elongation at break) were assessed, and their microstructure and intermolecular interactions were examined using scanning electron microscopy and Fourier transform infrared spectroscopy analysis. The results of this study demonstrate variations in the degree of esterification among the three pectin samples, with pomelo peel and lemon peel pectins exhibiting higher degrees of methylation compared to pectin from pitaya peel, which had a lower degree of methylation. However, no significant differences were observed regarding the films’ moisture content and water vapor permeability. Notably, the films made from pitaya peel pectin exhibited superior tensile strength and elongation at break to those derived from pomelo peel and lemon peel pectins. The pectin recovered from these fruit peels had great film properties and thus could be utilized for food packaging and edible films. Full article