Pectin Fractions Research Articles

Unveiling the structural properties of three pectin fractions variation affecting pulp browning during peach processing

Peach ripening accompanying by processing browning exacerbated has not been clarified in perspective of pectin fractions structural variation. This study investigated pectin fractions of water-soluble (WSP), trans-cyclohexane-1,2-diaminetetraacetic acid-soluble (CSP) and sodium carbonate-soluble (NSP) pectin in peach with different ripening times (24, 48, 72 h) and pretreatments (cold shock, CaCl2, the combination) effect on pulp browning in processing. Results showed that extended ripening time increases browning index and rate, along with increased reactive oxygen species levels, polyphenol oxidase and pectinase activities, and the structural of the pectin fractions. Thereinto, weight-average (Mw) and number-average (Mn) molecular weight of WSP increased, its linearity and branching degree decreased, while CSP and NSP showed decreases in Mw, Mn, and branching degree, but increases in linearity, rhamnogalacturonan structure proportion, and bending degree. Browning was correlated positively with Mn, Mw, rhamnogalacturonan proportion of WSP and CSP, linearity and bending degree of NSP, while negatively correlated with Mw of CSP and NSP and esterification degree and branching of all fractions. Thus, maintaining pectin polydispersity and rhamnogalacturonan branching helps protect the system from being quickly browning by compartmentalization effect of hindering the polyphenol substrates and enzymes possibly effective. This study offers insights into controlling browning through pectin fractions modulation.

Revealing the dominant role of pectin in regulating the stability of Huyou turbid juice: Insights from hydrodynamic cavitation

Pectin is an important substance affecting the turbidity stability of fruit juice. In this study, Huyou juice was treated by hydrodynamic cavitation, and endogenous pectin from Huyou juice was analyzed to determine the changes in the properties of Huyou pectin and to discuss the possible mechanisms by which pectin maintains the turbidity stability in Huyou juice. The results showed that hydrodynamic cavitation treatment could enhance the storage stability of Huyou juice. The results of the monosaccharide composition demonstrated that hydrodynamic cavitation treatment made the branched structure of endogenous pectin more pronounced. Results of XRD and FTIR analysis showed that the hydrodynamic cavitation treatment resulted in limited changes to the crystallinity and skeletal structure of pectin from Huyou juice. HC treatment enhanced the thermogravimetric stability of pectin in Huyou juice, with NSP exhibiting the highest stability. Additionally, HC treatment altered the rheological properties of the pectin fractions. In addition, correlation analysis was carried out to analyze the relationship between hydrodynamic cavitation and each component and index. In summary, the cavitation effect produced by hydrodynamic cavitation treatment could reduce the activity of PME in Huyou juice, change the linear structure of endogenous pectin and reduce the molecular weight and esterification degree of endogenous pectin, improving the turbidity stability of Huyou juice.

Elucidation of pineapple softening based on cell wall polysaccharides degradation during storage.

The degradation of cell wall polysaccharides in pineapple fruit during softening was investigated in the present study. Two pectin fractions and two hemicellulose fractions were extracted from the cell wall materials of 'Comte de Paris' pineapple fruit at five softening stages, and their compositional changes were subsequently analyzed. The process of softening of the fruit corresponded to an increase in the water-soluble pectin (WSP) and 1 M KOH-soluble hemicellulose (HC1) fractions, and a decrease in the acid-soluble pectin (ASP) fraction, which suggested the solubilization and conversion of cellular wall components. However, the content of 4 M KOH-soluble hemicellulose (HC2) decreased and then returned to the initial level. Furthermore, WSP, ASP, and HC1 showed an increment in the content of low molecular weight polymers while a decline in the high molecular weight polymers throughout softening, and not significant change in the contents of different molecular polymers of HC2 was observed. Moreover, the galacturonic acid (GalA) content in the main chain of WSP was maintained at a relatively constant level, but the major branch monosaccharide galactose (Gal) in WSP decreased. Different from WSP, the molar percentages of Gal and GalA in ASP decreased. The Gal or Arabinose (Ara) in HC1 exhibited a gradual decline while the molar percentages of xylose (Xyl) and glucose (Glu) in the main chain increased. These suggested that the main chain of ASP degraded while the branched chains of ASP, WSP and HC1 depolymerized during pineapple softening. Overall, fruit softening of 'Comte de Paris' pineapple was found to be the result of differential modification of pectin and hemicellulose.

Structural characterization of noni (Morinda citrifolia L.) pectin and its inhibitory activity on pancreatic lipase

This study aimed to investigate the physicochemical properties and biological activities of noni pectin (NP) extracted using various solvents, three fractions of noni pectin were obtained using traditional chemical and deep eutectic solvents. NPs are composed of various ratios of galacturonic acid, arabinose, rhamnose, xylose, glucose, and galactose with different yields, molecular weights, esterification degrees (DE), and microstructures. Among the fractions, noni pectin extracted with Betaine-citric acid (BNP) exhibited higher molecular weight, degree for esterification and pancreatic lipase (PL) inhibitory activity than the other fractions. Enzyme kinetic analysis indicated that BNP inhibited PL via a noncompetitive mechanism. BNP significantly altered the secondary structure of PL and quenched PL fluorescence, suggesting a static quenching mechanism. Isothermal titration calorimetry (ITC) further demonstrated that the binding of BNP to PL was spontaneous and driven by enthalpy, primarily mediated by hydrogen bonding and van der Waals forces. Molecular docking simulations also confirmed strong noncovalent interactions (hydrogen bonding and van der Waals forces) between BNP and PL. This study validated the high efficiency of the deep eutectic solvent-extracted noni pectin fraction in pancreatic lipase inhibition.

Structure formation mechanism of pectin-soy protein isolate gels: Unraveling the role of peach pectin fractions

This study investigated the macro & micro properties of the composite gels formed by soy protein isolate (SPI) and peach pectin fractions: water-soluble pectin (WSP), chelator-soluble pectin (CSP), and sodium carbonate soluble pectin (NSP). Specially, the interaction between pectin fractions and SPI was studied to explain the formation mechanism of the composite gels. WSP, as a high methoxyl pectin, exhibited rich branching (sugar ratio B = 3.10). CSP, as a low methoxyl pectin, depicted a high linearity. NSP, with low linearity (sugar ratio A = 6.14), contained numerous side chains. Due to the strong interaction between pectin fractions and SPI, the new composites with excellent dense network microstructures were formed, accompanied by increased apparent viscosity, higher G′ and G′′, and reduced particle size. XRD and FT-IR analysis highlighted the modifications in gel structures. SEM-dispersive X-ray spectroscopy observed elemental distribution and framework composition in pectin-SPI gels. Hydrophobic interaction was the most important chemical force in pectin-SPI binding. Molecular docking results indicated that galacturonic acid in pectin bound more strongly to 7S than to 11S, with tighter hydrogen bonds. Notably, WSP-SPI showed the lowest turbidity, indicating enhanced solubility and particle dispersion, which helped prevent aggregation. CSP-SPI demonstrated the highest G′ and G′′, ascribing to the high linearity and abundant carboxyl groups in CSP. NSP-SPI showed the highest apparent viscosity and irregular structure. Overall, the texture properties of pectin-SPI gels were driven by pectin's structure properties, which would provide new and valuable information for texture control in gel formulation.

Preparation, identification and α-glucosidase inhibitory activity of a high-methoxyl HG-type pectin from Liangping pomelo (Citrus maxima cv. Liangpin Yu) peel.

The peel from Liangping pomelo (Citrus maxima cv. Liangpin Yu) is generally discarded as waste during post-harvest handling and process, resulting in environmental pollution and waste. Pectin is the major component in pomelo peels and yields significant economic advantages. Thus, developing pomelo peel pectin (PPs) might be a feasible strategy to reduce environmental pollution caused by pomelo peel. The optimized PPs yield was 156.5 ± 2.5 g kg-1 under the inoculum size of 100 mg g-1, liquid-solid ratio of 31 mL g-1, fermentation time of 64 h, and fermentation temperature of 39 °C. PPs-6Aa, a pectin fraction from PPs purified with DEAE-52 cellulose, Sephadex G-100 and Sephadex G-75 column chromatography, showed higher α-glucosidase inhibitory activity, with an IC50 of 0.12 ± 0.03 mg mL-1. It was a high-methoxyl HG-type pectin of 42.8 kDa, and its repeat unit was →4)-α-GalpA-6-OMe-(1→4)-α-GalpA-6-OMe-(1→. Additionally, its α-glucosidase inhibitory activity might be related to hydrogen bonds formed with Lys-156, Glu-277, His-280, Asp-307, Arg-315, Asn-350, Asp-352 and Glu-411, and to hydrophobic interactions formed with Ser-157, Tyr-158, Asp-233, Gln-239, Ser-240, Phe-303, Thr-306, Leu-313, Phe-314, Gln-353 and Arg-442. These findings provide structural and bioactivity information on pectin from Liangping pomelo peel, which could be beneficial for the development of functional foods and pharmaceuticals. © 2024 Society of Chemical Industry.

Structural analyses of apricot pectin polysaccharides

Apricot pectin polysaccharides' fine structure was performed using HPSEC, HPAEC-PAD, GC–MS, NMR and FTIR spectroscopies. Purified pectin fraction (F1AP) was composed of D-galacturonic acid, L-rhamnose, D-arabinose and D-galactose, Mw ∼ 1588 kDa. F1AP was eluted by water and with 0.2 M NaCl from DEAE Sepharose fraction resulting in two distinct fractions, F1AP1 and F1AP6, with different structures, molecular weights, and conformations, providing insights into their structural diversity. F1AP1 neutral properties were related to its association with protein. F1AP1 had a backbone of (1 → 4)-linked-D-galacturonic acid and (1 → 2)-linked-L-rhamnopyranosyl residues branched with arabinogalactan including multiple glycosidic linkages of T-α-Araf, 3-α-Araf, 5-α-Araf, T-α-Arap, 2-α-Arap, t-Galp, 2-Galp, 3-Galp, 4-Galp, 6-Galp, 2,4-Galp, 3,4-Galp, 3,6-Galp and 4,6-Galp side chains, having methyl and acetylated groups, and a high molecular weight (1945 kDa). The Mark-Houwink exponent was 0.276, indicating a compact spherical conformation. While the other F1AP6 fraction consists predominately of less methylated HG regions of pectin polysaccharides. The molar mass of this fraction was 117.5 kDa, which adopted a stiffer and random coil conformation. This knowledge allows us to evaluate how the balance of chemical structure and physical properties of the two pectin domains may manifest itself in the isolated structure of apricot pectin and its applications.

Systematic multistep extraction process for the total valorization of fiber fractions from fruit seeds

This study explores a systematic multistep extraction process to valorize various fruit seeds (mango, cherry, lemon, pumpkin, avocado, litchi, peach, and apricot) by fractionating and isolating different fiber components. A first mild treatment, i.e., a protease-assisted extraction, was employed to disaggregate the plant cell structure and isolate soluble fibers. Subsequently, the insoluble residue underwent extraction by hot acidic water to solubilize and separate the pectin fraction. The remaining solid material was finally subjected to hydrothermal treatment to recover recalcitrant hemicellulose. Cherry, lemon, and pumpkin seeds emerged as the most advantageous by-products overall, showing great extractable quantities of low molecular weight pectin, pectin oligosaccharides, arabinogalactans, xylan, and xylo-oligosaccharides (extraction yields up to 63% and 68% in the first and third step, respectively). Peach and apricot seeds yielded fiber extracts that were similar to each other but distinct for each fraction, suggesting potential applications in different food formulations, albeit with lower yields. The purity of the extracts increased with each stage, reaching 42.6% for soluble fibers, 67.3% for pectin, and 76.1% for hemicellulose. Mango, avocado, and litchi seeds were less suitable for this method but could be utilized for starch recovery. This cascade process effectively maximizes the utilization of fruit by-products, offering a scalable solution for the sustainable extraction of valuable fibers.

Optical properties related to cell wall pectin contribute to determine the firmness and microstructural changes during apple softening

The modification of cell wall pectin is a major contributing factor to apple softening, associated with intensive variations of firmness and microstructure. Thus, a better understanding of the relationship between fruit optical properties, firmness, 3D microstructure and pectin is important for improving the optical detection of apple firmness. This work explored the optical properties in the wavelength range of 430 – 1650 nm related to cell wall pectin during apple softening, in order to better determine their firmness and 3D microstructural changes. An automatic single integrating sphere system was used to quantify absorption coefficient (μa) and reduced scattering coefficient (μs′). Micro-CT imaging, SEM and TEM were used to quantify the porosity, cell numbers, cell volume, volume fraction and microstructure of Fuji apples during storage. Firmness, pectin fractions, soluble solids content (SSC), titratable acid content (TAC), and moisture content were also measured. Results showed that depolymerization of pectin substances induces an increase in porosity (r = 0.97) and modification of cellular structure, leading to a decrease in firmness (r = 0.90). The reduction in firmness and cell numbers exhibited a strong positive correlation with both μa in the range of 1000 – 1650 nm and μs′ between 430 and 1000 nm with mean r of 0.88–0.96, whereas increases in covalent-soluble pectin (CSP) and porosity displayed a negatively correlated with these bands. The linear relationship indicates that Vis-NIRS at 980 nm could better predict apple firmness than μa or μs′ alone, with a coefficient of determination R2 of 0.97. Our findings suggest that the mechanism of optical technology for detecting apple firmness may be the interaction between tissue structure and pectin on μs′ and μa.

Melatonin Increases Root Cell Wall Phosphorus Reutilization via an NODependent Pathway in Rice (Oryza sativa).

Melatonin (MT) has been implicated in the plant response to phosphorus (P) stress; however, the precise molecular mechanisms involved remain unclear. This study investigated whether MT controls internal P distribution and root cell wall P remobilization in rice. Rice was treated with varying MT and P levels and analyzed using biochemical and molecular techniques to study phosphorus utilization. The results demonstrated that low P levels lead to a rapid increase in endogenous MT levels in rice roots. Furthermore, the exogenous application of MT significantly improved rice tolerance to P deficiency, as evidenced by the increased biomass and reduced proportion of roots to shoots under P-deficient conditions. MT application also mitigated the decrease in P content regardless in both the roots and shoots. Mechanistically, MT accelerated the reutilization of P, particularly in the root pectin fraction, leading to increased soluble P liberation. In addition, MT enhanced the expression of OsPT8, a gene involved in root-to-shoot P translocation. Furthermore, we observed that MT induced the production of nitric oxide (NO) in P-deficient rice roots and that the mitigating effect of MT on P deficiency was compromised in the presence of the NO inhibitor, c-PTIO, implying that NO is involved in the MT-facilitated mitigation of P deficiency in rice. Overall, our findings highlight the potential of MT as a promising strategy for enhancing rice tolerance to P deficiency and improving P use efficiency in agricultural practices.

RG-I-containing sugar domains from Centella Asiatica bind strongly to galectin-3 to inhibit cell–cell interactions

BackgroundCentella Asiatica has been shown to have beneficial value for the treatment of tumors. However, its active ingredients and molecular mechanisms of action have not been fully elucidated. Pectic polysaccharides are the primary active components from medicinal plants. Moreover, these polysaccharides are regarded as potential inhibitors of galectins, such as galectin-1, -3, -7, that generally promote tumor growth. Nevertheless, detailed structural analysis of pectic polysaccharides from Centella Asiatica is sorely lacking, as is knowledge of their interactions with galectins.MethodsWater-soluble pectic polysaccharides (WCAP) isolated from Centella Asiatica were purified into two homogeneous fractions (WCAP-A2b and WCAP-A5b) by a combination of anion-exchange and gel-permeation chromatography. Monosaccharide composition, FT-IR, NMR and enzymatic analyses were used to characterize their structural features. Furthermore, the interactions between galectin-1, -3, -7 and a series of these polysaccharides, including two pectin fractions and their structural domains produced by enzymatic hydrolysis, were evaluated by using hemagglutination and biolayer interferometry.ResultsWCAP-A2b and WCAP-A5b have weight averaged molecular weights of 30.0 kDa and 34.0 kDa, respectively, and both polysaccharides consist of rhamnogalacturonan I (RG-I), rhamnogalacturonan II (RG-II) and homogalacturonan (HG) domains, with mass ratios of 1.3: 1.0: 1.4 and 1.1: 1.0: 2.4, respectively. Their RG-I domains contain arabinan, galactan, and/or arabinogalactan, along with neutral sugar side chains that are more prevalent in WCAP-A2b than in WCAP-A5b. Hemagglutination and biolayer interferometry binding assays indicate that galectin-3 vis-à-vis galectin-1 and -7, binds strongly to the RG-I domain (likely via its neutral side chains) in WCAP-A5b, thereby inhibiting galectin-3-mediated cell–cell interactions.ConclusionsOur study provides structural information on pectin polysaccharides from Centella Asiatica. Results suggest that RG-I domains from WCAP-A5b and WCAP-A2b may be developed as potential inhibitors of galectin-3-mediated cell–cell adhesion and tumor growth.Graphical

Bamboo vinegar regulates the phytoremediation efficiency of Perilla frutescens (L.) Britt. by reducing membrane lipid damage and increasing cadmium retention

The gap between serious soil heavy metals pollution and inefficient soil remediation threatens human health. This study proposed a method to improve the phytoremediation efficiency using bamboo vinegar (BV) solution and the potential mechanism was discussed. The results demonstrated that the application of BV increases the content of cadmium (Cd) in vacuole and cell wall hemicellulose 2 in leaves of Perilla frutescens. Simultaneously, it enhanced enzyme activities of superoxide dismutase and catalase in leaves. Therefore, this process alleviated the damage of Cd to functional tissues of Perilla frutescens, thus improving the tolerance of plants to Cd. Moreover, the BV application reduced the Cd content bound by root cell wall pectin fractions and insoluble phosphate, subsequently improving the ability of oxalic acids to carry Cd to the aerial parts. Consequently, the aerial parts obtained a larger amount of Cd enrichment. Overall, the Transfer Factor of Cd from roots to stems and enrichment of Cd in Perilla frutescens were maximally increased by 57.70 % and 54.03 % with the application of 50-fold and 300-fold diluted BV under 2 mg·L−1 Cd stress, respectively. The results can provide a theoretical basis for the promotion of phytoremediation of Cd-contaminated soil treatment technology.

Effect of high-pressure-homogenisation on the interaction between pomegranate peel pectin fractions and anthocyanins in acidic environment

In this study, changes in the basic composition and structural characterisation of water-soluble pectin (WSP), homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) from pomegranate peel were investigated after high-pressure-homogenisation (HPH) at 50 MPa and 300 MPa. The interactions between three pectin and anthocyanin (ACN) complex were also studied. The three pectin fractions were mainly composed of galacturonic acid (34.95%–87.69%), all with low degrees of methyl-esterification ≤41.20%. HPH at 300 MPa increased the binding ratios of ACN to three pectin fractions by 34.22%–34.59%. Changes in the structural characterisation results of pectin confirmed that the depolymerisation and breakdown of the side chains of pectin after HPH promoted electrostatic interactions, hydrogen bond and hydrophobic interaction between pectin and ACN. Correspondingly, the thermal and storage stabilities of ACN in the complex was boosted after HPH at 300 MPa. This study provides insights into the interaction between pectin and ACN under HPH.

Antioxidant and immunomodulatory potential of cell wall polysaccharides from Harungana madagascariensis Lam

Numerous plant polysaccharides have demonstrated immunomodulatory and antioxidant potentials, and can be investigated as novel molecules with biological properties that may enhance immune function. The aim of this study was to assess the antioxidant and immunomodulatory properties of cell wall polysaccharides fractions isolated from Harungana madagascariensis (HM). Pectin fraction (PF) and hemicellulose fraction (HCF) were extracted and tested for their antioxidant properties using reducing power, 1,1-diphenyl-2-picryl hydrazyl (DPPH) and 2,2′-azino-bis-3-éthylbenzylthiazoline6-sulphonic acid (ABTS) radical scavenging assays, chelating activity and inhibition of lipid peroxidation. Their immunomodulatory activities were carried out on peritoneal macrophages targeting NADH oxidase and lysosomal enzyme activities as well as the production of nitric oxide (NO) and hydroperoxides (H2O2) during phagocytosis of Saccharomyces cereviceae. The polysaccharides fractions showed significant antioxidant and immunostimulatory activities via stimulation of NADH oxidase and lysosomal enzyme of peritoneal macrophages and production of NO and H2O2. Taken together, the results of this study indicate the potential of polysaccharides from H. madagascariensis as antioxidant and immunomodulator agents.

Higher molecular weight pectin inhibits ice crystal growth and its effect on the microstructural and physical properties of pectin cryogels

Understanding the formation of ice crystals is essential for tailoring the microstructure and physical properties of cryogels. This study investigated the effects and mechanisms of pectin molecular weight (Mw) on impacting ice crystal formation. Pectin fractions various Mw (10.13–212.20 kDa) were prepared by hydrothermal method. The solution of high Mw pectin fractions exhibited higher contact angle, lower water freedom, and stronger adsorption of water molecules. The splat experiment and molecular dynamic (MD) results confirmed that higher Mw pectin have stronger ice crystal growth inhibition activity than lower Mw pectin. Furthermore, the pore size distribution of the cryogel increased from 98–203 μm to 105–267 μm as the molecular weight decreased from 212.2 kDa to 121.0 kDa. Additionally, in the higher Mw pectin cryogel, stronger mechanical strength was observed. These findings suggested that changing the molecular weight of pectin has the potential to regulate the ice crystal growth, microstructure and physical properties of frozen products.

Effect of enzymatic modification on the structure and rheological properties of diluted alkali-soluble pectin fraction rich in RG-I

This study focuses on pectin covalently linked in cell walls from two sources, apples and carrots, that was extracted using diluted alkali, and it describes changes in the rheological properties of diluted alkali-soluble pectin (DASP) due to enzymatic treatment. Given DASP’s richness of rhamnogalacturonan I (RG-I), RG-I acetyl esterase (RGAE), rhamnogalacturonan endolyase (RGL), and arabinofuranosidase (ABF) were employed in various combinations for targeted degradation of RG-I pectin chains. Enzymatic degradations were followed by structural studies of pectin molecules using atomic force microscopy (AFM) as well as measurements of rheological and spectral properties. AFM imaging revealed a significant increase in the length of branched molecules after incubation with ABF, suggesting that arabinose side chains limit RG-I aggregation. Structural modifications were confirmed by changes in the intensity of bands in the pectin fingerprint and anomeric region on Fourier transform infrared spectra. ABF treatment led to a decrease in the stability of pectic gels, while the simultaneous use of ABF, RGAE, and RGL enzymes did not increase the degree of aggregation compared to the control sample. These findings suggest that the association of pectin chains within the DASP fraction may rely significantly on intermolecular interactions. Two mechanisms are proposed, which involve side chains as short-range attachment points or an extended linear homogalacturonan conformation favoring inter-chain interactions over self-association.

Physicochemical and antioxidant properties of pectin fractions extracted from lemon (Citrus Eureka) peels

Pectin, a natural polysaccharide, holds versatile applications in food and pharmaceuticals. However, there is a need for further exploration into extracting novel functional fractions and characterizing them thoroughly. In this study, a sequential extraction approach was used to obtain three distinct lemon pectin (LP) fractions from lemon peels (Citrus Eureka): LP extracted with sodium acetate (LP-SA), LP extracted with ethylenediaminetetraacetic acid (LP-EDTA), and LP extracted with sodium carbonate and sodium borohydride (LP-SS). Comprehensive analysis revealed low methyl-esterification in all fractions. LP-SA and LP-SS displayed characteristics of rhamnogalacturonan-I type pectin, while LP-EDTA mainly consisted of homogalacturonan pectin. Notably, LP-SA formed self-aggregated particles with rough surfaces, LP-EDTA showed interlocking linear structures with smooth planes, and LP-SS exhibited branch chain structures with smooth surfaces. Bioactivity analysis indicated that LP-SA had significant apparent viscosity and ABTS radical scavenging activity, while both LP-EDTA and LP-SS showed excellent thermal stability according to thermogravimetric analysis (TGA). Furthermore, LP-SS exhibited remarkable gel-forming ability and significant hydroxyl free radicals scavenging activity. In conclusion, this study presents a novel method for extracting various lemon pectin fractions with unique structural and bioactive properties, contributing insights for advanced applications in the food and pharmaceutical sectors.

Transcriptome analysis integrated with changes in cell wall polysaccharides of different fresh-cut chili pepper cultivars during storage reveals the softening mechanism

Cell wall disassembly and transcriptomic changes during storage of two fresh-cut chili pepper cultivars displaying contrasting softening rates were investigated. Results showed that Hangjiao No. 2 (HJ-2) softened more rapidly than Lafeng No. 3 (LF-3). Compared with LF-3, HJ-2 had a higher content of WSP, more side chains of RG-I in three pectin fractions, and higher activities of PME, PL, and β-Gal at day-0. During storage, HJ-2 showed more markable pectin solubilization, more severe degradation in CSP and NSP, and greater loss of side chains from RG-I in three pectin fractions, which were correlated with increased activities of PG and α-L-Af. Furthermore, the higher up-regulation of PG (LOC107870605, LOC107851416) and α-L-Af (LOC107848776, LOC107856612) were screened in HJ-2. In conclusion, the different softening rate between cultivars was not only due to the fundamental differences in pectin structure but also pectin degradation regulated by related enzymes and gene expression levels.

The Effect of Pulsed Electric Fields (PEF) on Nanostructure and Monosaccharides Composition of Pectin Fractions Extracted from Green and Red Tomatoes

The Effect of Pulsed Electric Fields (PEF) on Nanostructure and Monosaccharides Composition of Pectin Fractions Extracted from Green and Red Tomatoes

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

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