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The objective of the present investigation was to extract pectic polysaccharides from sesame seed hull and to determine their physicochemical and functional characteristics. The pectic polysaccharides in the seed hull were extracted with HCl and then collected at three ethanol concentrations of 30% (SSP30), 50% (SSP50), and 90% (SSP90). We found that SSP30 represented 75.6% of the total polysaccharides, and that it contained 76.39% galacturonic acid, with many HG domains and few short side chains in the RG-I domains. SSP30 exhibited the strongest hydroxyl radical scavenging activity among the three fractions, and was better able to stabilize the emulsions. Higher Mw pectic polysaccharides were firstly precipitated at lower ethanol concentrations, and the Mw of the precipitated pectic polysaccharides decreased with increasing ethanol concentration. These results provide important information on the structure and functional characteristics of sesame hull polysaccharides. This information can contribute to the future development of sesame hull polysaccharides for industrial purposes.

The use of pectin from coffee mucilage (PI) is an alternative to reduce the environmental impact of the wet processing coffee industries by applying it in the generation of degradable films. Hence, the aim of this work was to valorize industrial coffee waste as a source of pectin to prepare biodegradable films by a novel methodology (electrospraying), perform chemical characterization of pectin, and compare the films with a control method (casting) and pectin (citric, PC). Coffee mucilage pectin composition (PI) was different, having smaller galacturonic acid content (52.2%) than PC. The presence of neutral sugars (ribose, xylose, glucose), the high degree of esterification (84.92 ± 1.70) and the diffractogram and Raman spectra results, gave the basis to consider PI as a high methoxyl pectin. PI films showed different physical properties and structure than Pc, depending on the composition and method of production. Regarding mechanical and barrier characteristics, films prepared with pectin from coffee mucilage presented a typical behavior of rigid polymers; they were also more permeable to water vapor (2.91 ± 0.02 × 10−12 g/s m Pa) and were highly biodegradable and soluble in water. Due to these characteristics, the production of films from coffee mucilage pectin becomes a suitable alternative to give added value to this unexploited waste.

New edible coatings made of cassava starch and babassu flour were applied on cagaita and mangaba, two typical fruits from the Brazilian Cerrado, by dipping method. The effect of the babassu flour concentration (10, 30, or 50 g/100 g of starch) on the properties of coated fruits were studied. Fruits treated with cassava starch coating added with 50% babassu flour provided the most satisfactory results in terms of weight loss: mass loss was only 14% and 7% for cagaitas and mangabas, respectively. Meanwhile, uncoated fruits experienced greater weight loss up to 35%, indicating water loss due to product degradation during storage period and led to weight loss. Therefore, edible coatings protected fruits from dehydration. Uncoated fruits had the highest increase in a* parameter, which provided them with a more reddish color and faster ripening rate. Total soluble solids were stable for coated fruits along storage. All treatments showed an increase in pH values attributed to the degradation of organic acids in fruits. These results are in agreement with the acidity reduction reported for mangabas. Unlike mangabas, acid values increased in cagaitas which was associated with galacturonic acid formation by pectinesterase. Overall, cassava starch added with babassu flour is a promising material to produce edible coatings with adequate physical properties for food applications.

Better long-term survival of very preterm infants depends on optimizing the methods of their nutritional support. Today it is widely recognized that mother’s breast milk is the optimal enteral food for this extremely vulnerable infant population, becausebreast milk feeding reduces their morbidity and mortality. The advantages of breast milkfeeding are related to the biologically active components of breast milk, especially oligosaccharides (OS),concentration of which is only less than amount of lactose and fat. Available experimental and clinical data suggest that the positive clinical effect of the OS can be mostly structure-specific, since the spectrum of human milk oligosaccharides (HMO) is quite wide and includes more than 200 known different compounds. The content of the OS in breast milk is individual and depends on many factors. Despite the emergence of the potential for industrial synthesis of several HMOs, there are currently no results of interventional clinical studies with the use of food products for preterm infants enriched with such OS. Instead, the available data prove positive clinical effects of enrichment of formulas and breast milkwith synthetic OS, which, by their biological properties, mimicHMO. The largest number of such scientific data exists with respect to a special complex of OS, consisting of short-chain galactooligosaccharides (scGOS) and long-chain fructooligosaccharides (lcFOS) in a ratio of 9:1 with the possible addition of galacturonic acid. The article presentscurrent data on functional biology of HMO, clinical effectiveness of the use of synthetic OS in preterm infants, as well as future challenges and opportunities associated with the clinical application of the OS.

Florida juice processors amassed 51,000 metric tons of grapefruit juice processing residues (GFPR) in the 2018-19 season. GFPR contain valuable compounds such as pectic hydrocolloids, peel oil, sugars, phenolics and flavonoids that are ultimately lost or destroyed when they are converted to low value animal feed and molasses. If these compounds could be isolated from GFPR rather than destroyed, they could be converted to high value products. In this work, red and white GFPR were subjected to steam explosion in a batch system at 130, 150 and 170°C and 1, 2, 4 and 8 min holding time to identify the conditions for maximum recovery of pectic hydrocolloids, peel oil, sugars, phenolics and flavonoids. Steam explosion at 170°C and an 8 min hold time resulted in the recovery of 56-85% of total available glucose and fructose and the volatilization of 68-98% of the available peel oil. Of the phenolics and flavonoids analyzed, 61-62% could be extracted using steam explosion. Maximum recovery of pectic hydrocolloids, estimated by galacturonic acid content, was 1.6446 g • 100 g−1 for red GFPR at 130°C – 8 min and 1.557 g • 100 g−1 for white GFPR at 150°C – 2 min.

A novel heteropolysaccharide fraction (BBP-24-3) with a relative molecular weight of 145.1 kDa was isolated from blackberry fruits. The BBP-24-3 was mainly composed of arabinose, glucose, and galacturonic acid with a ratio of 5.30 : 3.60 : 91.10 mol%. Structural analysis showed that BBP-24-3 possessed a 1,6-linked β-D-Glcp, 1, 2, 3, 5 linked α-L-Araf, and 1, 4 linked α-D-GalpA backbone with branches substituted at the C-2 and C-5 positions of arabinose units, which included 1, 2, 3, 4 linked β-D-Glcp and T-linked β-D-GalpA. The conformation analysis indicated that BBP-24-3 exhibited a solid spherical structure with a uniform distribution in 0.1 M NaCl solution. The BBP-24-3 exhibited excellent α-glucosidase inhibitory activity with an IC50 value of 3.70 mg mL−1, which was due to the structural change, including α-helix and random coil of α-glucosidase caused by BBP-24-3. The current work suggests the potential utilization of BBP-24-3 as an α-glucosidase inhibitor in healthy food for reducing the postprandial blood glucose level.

The structure of lipid A from lipopolysaccharide (LPS) of Rhodomicrobium vannielii ATCC 17100 (Rv) a phototrophic, budding bacterium was re-investigated using high-resolution mass spectrometry, NMR, and chemical degradation protocols. It was found that the (GlcpN)-disaccharide lipid A backbone was substituted by a GalpA residue that was connected to C-1 of proximal GlcpN. Some of this GalpA residue was &beta, eliminated by alkaline de-acylation, which indicated the possibility of the presence of another so far unidentified substituent at C-4 in non-stoichiometric amounts. One Manp residue substituted C-4&prime, of distal GlcpN. The lipid A backbone was acylated by 16:0(3-OH) at C-2 of proximal GlcpN, and by 16:0(3-OH), i17:0(3-OH), or 18:0(3-OH) at C-2&prime, of distal GlcpN. Two acyloxy-acyl moieties that were mainly formed by 14:0(3-O-14:0) and 16:0(3-O-22:1) occupied the distal GlcpN of lipid A. Genes that were possibly involved in the modification of Rv lipid A were compared with bacterial genes of known function. The biological activity was tested at the model of human mononuclear cells (MNC), showing that Rv lipid A alone does not significantly stimulate MNC. At low concentrations of toxic Escherichia coli O111:B4 LPS, pre-incubation with Rv lipid A resulted in a substantial reduction of activity, but, when higher concentrations of E. coli LPS were used, the stimulatory effect was increased.

The objective of this work was to evaluate the effect of vacuum infusion of pectin methylesterase (PME) and calcium lactate (C6H10CaO6) in maintaining the firmness of minimally processed papaya, in order to maintain the quality and cellular integrity of the fruit. After minimal processing, the treatments used were: fruit without infusion (control), with H2O infusion, with PME infusion, with C6H10CaO6 infusion and with PME+C6H10CaO6 infusion. At zero times, four and eight days of storage, analyzes of total galacturonic acid, methanol, cell integrity, vitamin C, pH, acidity, soluble solids, damage, freshness and contamination were performed. Papaya treated with the PME+calcium combination showed an increase in firmness (5.8 N) on the eighth day of storage, differing from the control treatment (1.3 N), reporting the least leakage of electrolytes. On the fourth day, the fruit treated with PME+C6H10CaO6 showed the highest content of galacturonic acid and on the eighth day the highest content of methanol, indicating an effective action of the enzyme PME and calcium in this period. The PME+C6H10CaO6 treatment was effective in maintaining and improving the quality of papaya while preserving freshness, soluble solids content, acidity and pH throughout storage. El objetivo de este trabajo fue evaluar el efecto de la infusión al vacío de pectina metilesterasa (PME) y lactato de calcio (C6H10CaO6) en el mantenimiento de la firmeza de la papaya mínimamente procesada, con el fin de mantener la calidad e integridad celular del fruto. Después de un procesamiento mínimo, los tratamientos utilizados fueron: fruto sin infusión (control); con infusión de H2O; infundido con PME; con infusión de C6H10CaO6 y con infusión de PME+C6H10CaO6. En tiempos cero, cuatro y ocho días de almacenamiento, se realizaron análisis de ácido galacturónico total, metanol, integridad celular, vitamina C, pH, acidez, sólidos solubles, daño, frescura y contaminación. La papaya tratada con la combinación PME+calcio mostró un aumento de firmeza (5,8 N) en el octavo día de almacenamiento, diferenciándose del tratamiento control (1,3 N), reportando la menor fuga de electrolitos. Al cuarto día, la fruta tratada con PME+C6H10CaO6 tuvo el mayor contenido de ácido galacturónico y al octavo día el mayor contenido de metanol, lo que indica una acción efectiva de la enzima PME y calcio en este período. El tratamiento PME+C6H10CaO6 fue eficaz para mantener y mejorar la calidad de la papaya al tiempo que conservaba la frescura, el contenido de sólidos solubles, la acidez y el pH durante el almacenamiento. O objetivo deste trabalho foi avaliar o efeito da infusão a vácuo de pectina metilesterase (PME) e lactato de cálcio (C6H10CaO6) na manutenção da firmeza do mamão minimamente processado, visando manter a qualidade e a integridade celular do fruto. Após o processamento mínimo, os tratamentos empregados foram: fruto sem infusão (controle); com infusão de H2O; com infusão de PME; com infusão de C6H10CaO6 e com infusão de PME+C6H10CaO6. Nos tempos zero, quatro e oito dias de armazenamento foram realizadas análises de ácido galacturônico total, metanol, integridade celular, vitamina C, pH, acidez, sólidos solúveis, danos, frescor e contaminação. O mamão tratado com a combinação PME+cálcio apresentou um aumento da firmeza (5,8 N) no oitavo dia de armazenamento, diferindo em relação ao tratamento controle (1,3 N), reportando o menor vazamento de eletrólitos. No quarto dia, o fruto tratado com PME+C6H10CaO6 apresentou o maior teor de ácido galacturônico e no oitavo dia o maior teor de metanol, indicando uma ação efetiva da enzima PME e do cálcio nesse período. O tratamento PME+C6H10CaO6 foi eficaz em manter e melhorar a qualidade do mamão preservando o frescor, o conteúdo de sólidos solúveis, a acidez e o pH ao longo do armazenamento.

International audience; Increasing evidence shows that micronutrients can induce changes in cell wall (CW) properties in plants. A detailed knowledge of these changes will contribute to understand the beneficial and detrimental impacts of trace elements on plant development and defence. In the present work, the influence of foliar spray of manganese (Mn) on the composition of CW polysaccharides and soluble sugars was investigated in cucumber leaves using spectrophotometric and chromatographic techniques. Cucumber seedlings were hydroponically cultured under controlled situations for 21 days. At the two-leaf stage, the above facade of cucumber leaves was fertilized with MnSO(4)solutions at various dosages (1.8, 4.5 and 7.2 mM). Results showed that the foliar Mn spray decreased the galacturonic acid (GalA) content, while it increased the degree-of-methyl-esterification (DM) of pectin. The amounts of fucose, arabinose and galactose diminished upon Mn application. The contents of rhamnose and xylose decreased or did not change by Mn treatment. The glucose level enhanced at low concentration of Mn (1.8 mM), but it decreased at medium and high concentrations of Mn (4.5 and 7.2 mM). The increase of mannose content was significant only at medium concentration of Mn. Overall, the amount of total hemicellulose increased at 1.8 mM concentration of Mn, while a decrease was observed at 4.5 and 7.2 mM concentrations of Mn. The cellulose content decreased at low and high concentrations of Mn, although it remained unchanged at medium concentration of Mn. Generally, the total contents of CW polysaccharides increased at low concentration of Mn, but they decreased at the higher concentrations of Mn. Such changes can be important in plant resistance to environmental stresses via reduction of permeability against fungal pathogens and decrease of water loss from tissues under stresses such as drought and salinity.

A sequential combination of laccase pretreatment and acid extraction of pectin from pomelo peels was performed in this study. By using a laccase dose of 10 U/g, the yield and galacturonic acid content of the extracted pectin were 21.67% and 75.74%, respectively, which reflected an improvement by nearly 30% and 44% relative to the extraction process without laccase. Moreover, the degree of esterification of the extracted pectin was significantly improved as the laccase concentration was increased from 0 to 10 U/g but did not affect the molecular weight. Besides, the enzyme-treated sample displayed more than 29% loss of total lignin, in which the acid soluble lignin and the acid insoluble lignin were removed by over 15% and 33%, respectively. Scanning electron microscopy indicated that the penetration and partial destruction of the pomelo peel cell wall due to laccase might be one of the main reasons why laccase pretreatment could release pectin from cell wall complexes and increase the pectin yield in subsequent acid extraction processes.

This study was to identify active pectin fragments of high in vitro anti-proliferation activities against human colon adenocarcinoma Caco-2 cells, using various pectin fragment preparations dominant with rhamnogalacturonan I (RG-I), rhamnogalacturonan II (RG-II), and galacturonic acid oligomers (GAOS). The samples were prepared from citrus high and low methoxy pectins (HPE and LPE) by endo-α-D-(1,4)-polygalacturonase action coupling with a green process as ultrafiltration (membrane molecular weight cut off > 10k, 1k-10k, and

Dietary fibers perform various physiological and metabolic functions in the human body. Pectin, a water-soluble dietary fiber, is a natural complex heteropolysaccharide composed of galacturonic acid residues and a variety of neutral sugars such as rhamnose, galactose, and arabinose. It is a constituent of the cell wall and is conserved in all terrestrial plants. Besides the health benefits associated with dietary fibers, new health-related functions are being explored, particularly those related to the bioactive roles in inducing morphological changes in the small intestine. This review discusses the structure of pectin, its widely known physiological functions, and the new developments in pectin research.

Background: Industrial extraction of orange juice produces a large amount of waste that affects the environment and gives rise to important economic losses; at the same time, information about the composition of the waste is still limited. The present study carried out an exhaustive chemical and physicochemical characterization of the residues in the waste, aiming to increase their potential application for the extraction of functional ingredients.; Results: Four different products (three solids and one liqueur) were provided by the industry. The overall characterization indicated that carbohydrates comprised the main components. During processing, carbohydrate derivatives were formed such as those corresponding to the initial steps of the Maillard reaction. In this sense, furosine was demonstrated to be a suitable indicator with respect to the control of the process. Although the phenolic content substantially decreased (by up to 57%) as the processing proceeded, the antioxidant capacity was affected to a much lesser extent (∼10%). Dehydrated products were rich in galacturonic acid and hardly any change was detected during their elaboration. The liqueur by-product was found to have a much higher level of fructose than glucose and sucrose.; Conclusion: Orange juice waste obtained industrially under the conditions described in the present study could be used as a source of pectic derivatives or fructose in the case of solid or liquid by-products, respectively. The results reported here could diversify the present application of these products as a source of food ingredients, contributing to an improvement in their utilization. © 2018 Society of Chemical Industry.; © 2018 Society of Chemical Industry.

A new and robust high performance thin-layer chromatography (HPTLC) method has been developed for carbohydrate analysis in biorefinery streams. The samples can be applied directly from industrial streams without any purification or pretreatment, saving time and resources and avoiding potential alterations to the samples’ composition. The main neutral monosaccharides found in wood-based lignocellulosic biomass – glucose, xylose, mannose, arabinose and galactose – can be separated and quantified using acetonitrile:1-pentanol:water (4:1:1, v/v/v) on silica impregnated with a phosphate buffer. Common minor compounds – glucuronic acid, galacturonic acid, rhamnose, cellobiose and hydroxymethylfurfural (HMF) – can also be detected qualitatively. Matrix compounds, which are a major part of biomass, do not interfere with the analysis. Validation showed that the method is selective, has good repeatability and has limits of detection and quantification in the nanogram range. The visual fingerprint offers information on the samples’ constituents in the case of unknown samples. Also, incomplete hydrolysis is indicated by the visibility of oligosaccharides.

In this study, an RG-I pectin DNP-W6 was isolated from the stems of Dendrobium nobile Lindl. (Orchidaceae). It contained mannose, glucose, galactose, galacturonic acid and rhamnose in a molar ratio of 0.6: 1.0: 1.5: 1.1: 1.0. Its structural features were revealed by chemical, physical and spectral analysis. The results suggested that DNP-W6 possessed a backbone of a disaccharide of →4)-α-GalAp-(1→2)-α-Rhap-(1→, with approximate 50% substitution at O-4 of the rhamnopyranosyl residues. The side chains were neutral chains including galactosyl, mannosyl and glucosyl chains. The acetyl content was estimated to be 8.9%. The immunological results indicated that DNP-W6 and its derivatives exhibited different immunological activities in vitro, showing that the side chains and acetyl groups had an important effect on the expression of immunological activities.

The traditional view considers that Chenpi (dried citrus peel) stored over the long-term has better health efficacies compared to fresh Chenpi, although the detailed mechanism responsible for this remains obscure.; Results: The three water-soluble pectic polysaccharides (CPP1, CPP5 and CPP10) were obtained from 1-, 5- and 10-year Chenpi, respectively, and their physicochemical characteristics and intestinal immunomodulating activities were investigated and compared. The results obtained showed that CPP5 and CPP10 demonstrated a lower dynamic viscosity and degree of methylesterification, as well as a higher molecular heterogeneity, compared to CPP1. Monosaccharide composition analysis indicated that CPP1 was composed of arabinose, galacturonic acid and galactose, and a small amount of rhamnose; however, CPP5 and CPP10 consisted of arabinose, galacturonic acid, galactose, glucose and xylose, and a small amount of rhamnose. With the extension of storage period of Chenpi, the content of soluble conjugate phenolic acids increased in the pectic polysaccharide. Furthermore, it was confirmed that the pectic polysaccharides extracted from the 5-year and 10-year Chenpi could significantly enhance the proliferation of bone marrow cells via activating the Peyer's patch cells in vitro.; Conclusion: The present study demonstrates the differences in the pectic polysaccharides from Chenpi with different storage periods and also confirms that the pectic polysaccharides extracted from Chenpi stored over the long-term had more significant intestinal activities compared to that obtained from the fresh Chenpi. This phenomenon might partly explain why the Chenpi stored over the long-term has better healthcare effects. © 2018 Society of Chemical Industry.; © 2018 Society of Chemical Industry.

Chinese quince seed gum (CQSG) is a novel potential viscosifier or stabilizer with good storage stability. In this work, CQSG was extracted from the surface of Chaenomeles sinensis (Chinese quince) seeds, and purified by DEAE-Sepharose Fast-Flow and Sephacryl S-400 HR chromatography; three fractions were obtained (CQSG-1, -2, -3). The main fraction (CQSG-2) was investigated by monosaccharide analysis, methylation and one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) experiments to determine its structure. Results showed that CQSG-2 is composed of arabinose (Ara), glucose (Glu), xylose (Xly), galacturonic acid (Gala) and glucuronic acid (Glua) in a molar ratio of 4.0:0.3:15.2:4.2:3.8. →4-β- d -Xylp-1→ and →2, 4-β- d -Xylp-1→ constitute the backbone in a ratio of 5.9:4.5, and the Arap-1→, α- d -GalpA-1→, →2-α- d -GlcpA-1→, →4-β- d -Glcp-1→, and →2, 3, 5- l -Araf-1→ form the branched chain. The molecular aggregation of CQSG-2 with high molecular weight (Mw) (1.4 × 106 Da) was strong compared with CQSG-1 and CQSG-3. This is the first systematic elucidation of the structure of Chinese quince seed gum, and it provides the basis for developing applications for this gum in the food and pharmaceutical industries.

Shigella is a leading diarrheal cause of morbidity and mortality worldwide, especially in low- and middle-income countries and in children under five years of age. Increasing levels of antimicrobial resistance make vaccine development an even higher global health priority. S. flexneri serotype 6 is one of the targets of many multicomponent vaccines in development to ensure broad protection against Shigella. The O-antigen (OAg) is a key active ingredient and its content is a critical quality attribute for vaccine release in order to monitor their stability and to ensure appropriate immune response. Here, the optimization of two methods to quantify S. flexneri 6 OAg is reported together with the characterization of their performances. The optimized Dische colorimetric method allows a tenfold increment of the sensitivity with respect to the original method and is useful for fast analysis detecting selectively methyl-pentoses, as rhamnose in S. flexneri 6 OAg. Also, a more specific HPAEC-PAD method was developed, detecting the dimer galacturonic acid-galactosamine (GalA-GalN) coming from S. flexneri 6 OAg acid hydrolysis. These methods will facilitate characterization of S. flexneri 6 OAg based vaccines. The colorimetric method can be used for quantification of other polysaccharide containing methyl-pentoses, and the HPAEC-PAD could be extended to other polysaccharides containing uronic acids.

Compositions, molecular characteristics, and rheological properties of the water-extractable polysaccharides from okra were investigated. The proportions of galacturonic acid and monosaccharides in...

La pectina es un polisacárido con características hidrocoloidales, gelificantes y estabilizantes, usada ampliamente en la elaboración de productos cosméticos, alimenticios, farmacéuticos, entre otros. Considerando su importancia y aplicación industrial se realizó el presente trabajo con el objetivo de evaluar la cascarilla de cacao nacional (Theobroma cacao Linneo), como fuente de este polímero natural y las condiciones determinantes en su proceso de extracción. Se empleó cascarilla de cacao la cual corresponde a una mezcla de diferentes materiales (Criollo, Forastero y Trinitario) y se implementó un método de extracción por reflujo con ácido cítrico. Se realizaron ensayos preliminares donde se evaluaron diferentes tiempos (100, 95, 85 y 75 minutos) y temperaturas (95, 90, 80 y 70 ºC). Se realizó un análisis de varianza con un diseño 22 con las condiciones con las que se obtuvo los mayores porcentajes de metoxilo y de ácido galacturónico. Según los resultados el rendimiento de extracción de pectina se incrementó proporcionalmente a los factores tiempo y temperatura, sin embargo, el porcentaje de metoxilo no presentó una gran variación (2,65±0,16% y 2,90±0,03%), caracterizándose como de bajo metoxilo. Las mejores condiciones de extracción de la pectina fueron a 70 °C y 95 con un rendimiento de 8,82 g de pectina por 100 g de cascarilla. La pectina obtenida presentó un alto grado de esterificación (71,88±0,78%) y un contenido de 26,86%±0,86 de ácido galacturónico. Esto indica que la cascarilla procedente de la industria chocolatera nacional puede ser considerada una alternativa para la obtención de pectina

This work investigated effects of the galacturonic acid content (GA), degree of methoxylation (DM), degree of amidation (DA) and molecular weight (MW) of pectin on the pasting properties of rice starch (RS). Pectins with varying structures were selected randomly. Different pectins when added to RS showed significant differing (p

A new lectin from Aplysia dactylomela eggs (ADEL) was isolated by affinity chromatography on HCl-activated Sepharose™ media. Hemagglutination caused by ADEL was inhibited by several galactosides, mainly galacturonic acid (Ka = 6.05 × 106 M−1). The primary structure of ADEL consists of 217 residues, including 11 half-cystines involved in five intrachain and one interchain disulfide bond, resulting in a molecular mass of 57,228 ± 2 Da, as determined by matrix-assisted laser desorption/ionization time of flight mass spectrometry. ADEL showed high similarity with lectins isolated from Aplysia eggs, but not with other known lectins, indicating that these lectins could be grouped into a new family of animal lectins. Three glycosylation sites were found in its polypeptide backbone. Data from peptide-N-glycosidase F digestion and MS suggest that all oligosaccharides attached to ADEL are high in mannose. The secondary structure of ADEL is predominantly β-sheet, and its tertiary structure is sensitive to the presence of ligands, as observed by CD. A 3D structure model of ADEL was created and shows two domains connected by a short loop. Domain A is composed of a flat three-stranded and a curved five-stranded β-sheet, while domain B presents a flat three-stranded and a curved four-stranded β-sheet. Molecular docking revealed favorable binding energies for interactions between lectin and galacturonic acid, lactose, galactosamine, and galactose. Moreover, ADEL was able to agglutinate and inhibit biofilm formation of Staphylococcus aureus, suggesting that this lectin may be a potential alternative to conventional use of antimicrobial agents in the treatment of infections caused by Staphylococcal biofilms.

The switch from the traditional fossil-based industry to a green and sustainable bioeconomy demands the complete utilization of renewable feedstocks. Many currently used bioconversion hosts are unable to utilize major components of plant biomass, warranting the identification of microorganisms with broader catabolic capacity and characterization of their unique biochemical pathways. d-Galacturonic acid is a plant component of bioconversion interest and is the major backbone sugar of pectin, a plant cell wall polysaccharide abundant in soft and young plant tissues. The red basidiomycete and oleaginous yeast Rhodosporidium toruloides has been previously shown to utilize a range of sugars and aromatic molecules. Using state-of-the-art functional genomic methods and physiological and biochemical assays, we elucidated the molecular basis underlying the efficient metabolism of d-galacturonic acid. This study identified an efficient pathway for uronic acid conversion to guide future engineering efforts and represents the first detailed metabolic analysis of pectin metabolism in a basidiomycete fungus., Biorefining of renewable feedstocks is one of the most promising routes to replace fossil-based products. Since many common fermentation hosts, such as Saccharomyces cerevisiae, are naturally unable to convert many component plant cell wall polysaccharides, the identification of organisms with broad catabolism capabilities represents an opportunity to expand the range of substrates used in fermentation biorefinery approaches. The red basidiomycete yeast Rhodosporidium toruloides is a promising and robust host for lipid- and terpene-derived chemicals. Previous studies demonstrated assimilation of a range of substrates, from C5/C6 sugars to aromatic molecules similar to lignin monomers. In the current study, we analyzed the potential of R. toruloides to assimilate d-galacturonic acid, a major sugar in many pectin-rich agricultural waste streams, including sugar beet pulp and citrus peels. d-Galacturonic acid is not a preferred substrate for many fungi, but its metabolism was found to be on par with those of d-glucose and d-xylose in R. toruloides. A genomewide analysis by combined transcriptome sequencing (RNA-seq) and RB-TDNA-seq revealed those genes with high relevance for fitness on d-galacturonic acid. While R. toruloides was found to utilize the nonphosphorylative catabolic pathway known from ascomycetes, the maximal velocities of several enzymes exceeded those previously reported. In addition, an efficient downstream glycerol catabolism and a novel transcription factor were found to be important for d-galacturonic acid utilization. These results set the basis for use of R. toruloides as a potential host for pectin-rich waste conversions and demonstrate its suitability as a model for metabolic studies with basidiomycetes. IMPORTANCE The switch from the traditional fossil-based industry to a green and sustainable bioeconomy demands the complete utilization of renewable feedstocks. Many currently used bioconversion hosts are unable to utilize major components of plant biomass, warranting the identification of microorganisms with broader catabolic capacity and characterization of their unique biochemical pathways. d-Galacturonic acid is a plant component of bioconversion interest and is the major backbone sugar of pectin, a plant cell wall polysaccharide abundant in soft and young plant tissues. The red basidiomycete and oleaginous yeast Rhodosporidium toruloides has been previously shown to utilize a range of sugars and aromatic molecules. Using state-of-the-art functional genomic methods and physiological and biochemical assays, we elucidated the molecular basis underlying the efficient metabolism of d-galacturonic acid. This study identified an efficient pathway for uronic acid conversion to guide future engineering efforts and represents the first detailed metabolic analysis of pectin metabolism in a basidiomycete fungus.

Pomelo albedo was extracted with water to obtain the high methoxyl pectin, labeled as PAP. The physicochemical and rheological properties of PAP were determined. The effects of PAP addition on rheological property and thermal stability of konjac glucomannan (KGM) were evaluated. Results indicated that PAP was composed of arabinose, glucose and galacturonic acid with a relative mass percentage of 7.2%: 9.5%: 83.3%, and exhibited an average molecular weight of 56.6 kDa. The degree of esterification of PAP was 65.5%, showing PAP was a kind of high methoxyl pectin. Apparent viscosity of PAP was concentration-dependently increased, while it was slightly enhanced with salt (NaCl or CaCl2) addition. Moreover, the addition of PAP declined the apparent viscosity, elastic property and thermal stability of KGM. It can be concluded that interaction was occurred between KGM and PAP. Meanwhile, the interaction mechanism between KGM and PAP has been preliminarily proposed. The present study can provide some references for the application of PAP and support the combination usage of this pectin and KGM in food and other industries.

Pectin was obtained with citric acid and subcritical water extraction from cacao pod husk with or without a previous step consisting of a supercritical fluid extraction of phenols. By subcritical conditions a higher yield (10.9%) was attained in a time 3-fold shorter than that obtained by conventional extraction (˜8%) and a greater effectiveness in the recovery of pectin with higher molecular weight (750 kDa) was also found. Regarding pectin structure, galacturonic acid and degree of methyl esterification content were similar (˜55 and ˜36%, respectively) in both methods. Moreover, pectin recovered by citric acid presented 2-fold higher amount of impurities as compared to subcritical water extraction. Hardly any effects of a previous supercritical treatment were observed in the structure and composition of pectin, indicating the efficiency of the integrated supercritical carbon dioxide and subcritical water extraction as green processes for the obtainment of phenol and pectin from cacao pod husk., This work has been funded by MINECO of Spain, Projects AGL2014-53445- R and AGL2017-89417-R.N. Muñoz-Almagro thanks to Ministry of Economy of Spain for providing her FPI predoctoral fellowship. L. Valadez-Carmona is grateful to Consejo Nacional de Ciencia y Tecnología (CONACyT) for the fellowship grant number 254415 and IPN for the financial support to accomplishment of research internship in Institute of Food Science Research (CSIC-UAM).

The esterification of galacturonic acid with methanol and/or acetic acid is important for the structural analysis of pectin. Although several methods have been reported for determining the degree of methylesterification (DM) and acetylation (DAc), the present study compares and optimizes three methods (titration, FT-IR and HPLC) using commercial citrus pectin (CP). Our results showed that the DM of CP was 47.0%, 47.6% and 48.0% as determined by titration, FT-IR and HPLC, respectively, suggesting that DM determination is nearly identical using any of these methods. However, the titration approach requires more sample than the other two. HPLC showed that the DAc of CP was 1.6%, an approach that can be used to determine the DM and DAc of pectin simultaneously. Here, we simplified and optimized sample treatment for HPLC analysis and compared it with the reported literature. Our results provide useful information for choosing appropriate methods for determining the DM and DAc of pectin based on various sample properties and experimental conditions.

The free-living Gram-negative bacterium Oligotropha carboxidovorans (formerly: Pseudomonas carboxydovorans), isolated from wastewater, is able to live in aerobic and, facultatively, in autotrophic conditions, utilizing carbon monoxide or hydrogen as a source of energy. The structure of O. carboxidovorans lipid A, a hydrophobic part of lipopolysaccharide, was studied using NMR spectroscopy and high-resolution mass spectrometry (MALDI-ToF MS) techniques. It was demonstrated that the lipid A backbone is composed of two d-GlcpN3N residues connected by a &beta, (1&rarr, 6) glycosidic linkage, substituted by galacturonic acids (d-GalpA) at C-1 and C-4&rsquo, positions. Both diaminosugars are symmetrically substituted by 3-hydroxy fatty acids (12:0(3-OH) and 18:0(3-OH)). Ester-linked secondary acyl residues (i.e., 18:0, and 26:0(25-OH) and a small amount of 28:0(27-OH)) are located in the distal part of lipid A. These very long-chain hydroxylated fatty acids (VLCFAs) were found to be almost totally esterified at the (&omega, 1)-OH position with malic acid. Similarities between the lipid A of O. carboxidovorans and Mesorhizobium loti, Rhizobium leguminosarum, Caulobacter crescentus as well as Aquifex pyrophylus were observed and discussed from the perspective of the genomic context of these bacteria.

A pilot-scale extraction of sunflower pectin with 0.74% (w/v) sodium citrate (72 °C, 194 min) and different procedures of purification including alcohol precipitation, ultrafiltration (UFDF) and microfiltration (MFDF) with diafiltration were carried out. Considering the alcohol treatment, the yields were similar at laboratory and pilot-scale (~8.9%), demonstrating the efficiency of the scale-up. With respect to membrane processes, the best results were obtained with UFDF, showing the highest yield (13.3%) and pectin concentration higher than 90%. In all cases, pectins presented very low amount (~1%) of glucose and mannose, monosaccharides not included in the pectin structure. Detailed NMR analysis and functional properties (emulsifying and viscosity) that were also assessed corroborated the good quality of UFDF obtained pectin. These results point out that the obtainment of sunflower pectin of good quality can be achieved at pilot-scale by the extraction with sodium citrate and purification with membrane separation, eco-friendly alternatives to conventional procedures., This work has been funded by MINECO of Spain, Project AGL2014-53445- R. N. Muñoz-Almagro thanks to Ministry of Economy of Spain for providing her FPI predoctoral fellowship.

Poly(galacturonic acid) (PGuA) is an important natural biopolymer, however its potential has not been realized due to its anionic nature and rigid structure, which limits its processability into fine films and fibres. This study aims at modifying the solution properties of PGuA in alkaline medium (aq. sodium hydroxide) to enable their conversion into electrospun nanofibers. Addition of anionic surfactants was found to play an important role in individualizing the PGuA chains that lead to formation of small spindle shaped fibers of length ranging from 2 to 10 μm and diameter from 287 to 997 nm. However, continuous fibers were not formed even at concentrations higher than the critical concentration. Addition of small amount (10–30%) of high molecular weight PVA resulted in formation of continuous fibers. Correlation of fiber diameters of PGuA/PVA with the rheological properties suggested a strong dependence of diameter with the elasticity of the blend solutions. Such PGuA based fibers may be utilized in various biomedical applications.

In this work, response surface methodology and adaptive neuro-fuzzy inference system approaches were used to predict and model effect of extraction conditions of pectin from medlar fruit (Mespilus germanica L.). The pectin extracted at optimized conditions (89 °C, 4.83 h and 4.2 pH) could be classified as high methoxyl pectin. Sugar composition analysis showed that pectin was mainly composed of D -galacturonic acid, L -arabinose, L -rhamnose, D -galactose and D -glucose. Fourier Transform Infrared Spectroscopy, RAMAN and nuclear magnetic resonance spectra confirmed molecular structure, revealing presence of D -galacturonic acid backbone. X-ray diffraction patterns revealed an amorphous structure. Differential scanning calorimetry showed endothermic (123 °C) and exothermic peaks (192 °C). Thermogravimetric analysis revealed three decomposition regions, 50–225 °C, 225–400 °C and 400–600 °C. Steady and dynamic shear analyses revealed that pectin had a pseudo-plastic behavior with storage (G′) and loss (G″) modulus increasing with increment in frequency, indicating viscoelastic structure more predominantly elastic than viscous.

In nature, the fungus Aspergillus niger degrades plant biomass polysaccharides to monomeric sugars, transports them into its cells, and uses catabolic pathways to convert them into biochemical building blocks and energy. We show that when grown in liquid cultures, A. niger takes up plant-biomass derived sugars in a largely sequential manner. Interestingly, this sequential uptake was not mediated by the fungal general carbon catabolite repressor protein CreA. Furthermore, transcriptome analysis strongly indicated that the preferential use of the monomeric sugars is arranged at the level of transport, but it is not reflected in transcriptional regulation of sugar catabolism. Therefore, the results indicate that the regulation of sugar transport and catabolism are separate processes in A. niger.

Structure of the O-specific polysaccharide from Pseudomonas chlororaphis subsp. aureofaciens UCM B-306 was elucidated by sugar analysis along with 1D and 2D 1 H and 13 C NMR spectroscopy. The polysaccharide is built up of trisaccharide repeats containing d -rhamnose, 2,4-diacetamido-2,4,6-trideoxy- d -glucose ( d -QuiNAc4NAc), and 2-acetamido-2-deoxy- d -galacturonic acid ( d -GalNAcA), which is amidated in ∼40% repeats. It was suggested that the O-polysaccharide has a blockwise structure, which can be presented as follows: -[→3)-α- d -Rha p -(1→4)-α- d -Gal p NAcA-(1→3)-α- d -Qui p NAc4NAc-(1-] n → and -[→3)-α- d -Rha p -(1→4)-α- d -Gal p NAcAN-(1→3)-α- d -Qui p NAc4NAc-(1-] m →, where GalNAcAN indicates 2-acetamido-2-deoxy- d -galacturonamide, n: m =∼3:2.

Separation and characterization of complex mixtures of pectic oligosaccharides still remains challenging and often requires the use of multiple analytical techniques, especially when isomeric structures are present. In this work, it is demonstrated that the coupling of hydrophilic interaction chromatography (HILIC) to traveling-wave ion mobility mass spectrometry (TWIMMS) enabled the simultaneous separation and characterization of complex mixtures of various isomeric pectic oligosaccharides. Labeling of oligosaccharides with 3-aminoquinoline (3-AQ) improved MS-ionization efficiency of the oligosaccharides and reduced the complexity of the product ion mass spectra, without losing resolution of the HILIC separation. In addition, labeling enabled quantification of oligosaccharides on molar basis using in-line fluorescence detection. Isomeric structures were distinguished using TWIMMS. The 3-AQ-HILIC–TWIMMS method was used to characterize a series of isomeric sugar beet rhamnogalacturonan I derived oligosaccharides carrying a glucuronic acid substituent. Thereby, some novel structural features were identified for the first time: glucuronic acid was attached to O-3 or to O-2 of galacturonic acid residues and a single galacturonic acid residue within an oligomer could contain both an acetyl group and a glucuronic acid substituent.

Pectin containing agricultural by-products are potential sources of a new class of prebiotics known as pectic oligosaccharides (POS). In general, pectin is made up of homogalacturonan (HG, α-1,4-linked galacturonic acid monomers) and rhamnogalacturonan (RG, alternate galacturonic acid and rhamnose backbone with neutral side chains). Controlled hydrolysis of pectin containing agricultural by-products like sugar beet, apple, olive and citrus by chemical, enzymatic and hydrothermal can be used to produce oligo-galacturonides (GalpOS), galacto-oligosaccharides (GalOS), rhamnogalacturonan-oligosaccharides (RGOS), etc. However, extensive research is needed to establish the role of POS, both as a prebiotic as well as therapeutic agent. This review comprehensively covers different facets of POS, including the nature and chemistry of pectin and POS, potential agricultural residual sources of pectin, pre-treatment methods for facilitating selective extraction of pectin, identification and characterization of POS, health benefits and important applications of POS in food and feed. This review has been compiled to establish a platform for future research in the purification and characterization of POS and for in vivo and in vitro studies of important POS, so that they could be commercially exploited.

Developing hemp fibre composites for structural applications requires both reconsideration and optimisation of the transformation processes to obtain stable, high-quality fibre reinforcements. In this context, field retting remains an important issue because it is weather dependent and has not been completely mastered by the hemp industries. Retting can be achieved voluntarily to facilitate fibre separation and extraction from the stalks prior to mechanical decortication. However, retting can also be involuntary and result from climatic misfortune and unforeseeable events at the time of harvest. Therefore, this study aimed to quantify the influence of involuntary and non-controlled field retting on the physicochemical and mechanical properties of industrial hemp bast fibres. A wide spectrum of analytical techniques was applied, including colour spectrophotometry; morphological, microscopic (SEM), surface (EDX, roughness), biochemical (HPLC and pXRD) and thermogravimetric (TGA) analyses; dynamic vapour sorption; and tensile characterisation. The results indicate that retting induced a decrease in the average width of fibre elements after mechanical processing and a loss of pectic substances. We also observed a change in colour from yellow to dark grey, an increase in surface roughness and an increase in the decomposition temperature for the third mass loss region. A decrease in tensile properties at the scales of both single and technical fibres was also observed. Since no significant decrease in cellulose content was measured, this decay in mechanical performance was connected with both the significant degradation of hemicelluloses and a decrease in the fraction of crystalline cellulose that was quantified in this work. 52;10

International audience; Pectins are complex branched polysaccharides present in primary cell walls. As a distinctive feature, they contain high amount of partly methyl-esterified galacturonic acid and low amount of rhamnose and carry arabinose and galactose as major neutral sugars. Due to their structural complexity, they are modifiable by many different enzymes, including hydrolases, lyases, and esterases. Their peculiar structure is the origin of their physicochemical properties. Among others, their remarkable gelling properties make them a key additive for food industries. Pectin-degrading enzymes and -modifying enzymes may be used in a wide variety of applications to modulate pectin properties or produce pectin derivatives and oligosaccharides with functional as well as nutritional interests. This paper reviews the scientific information available on pectin structure, pectin-modifying enzymes, and the use of enzymes to produce pectin with controlled structure or pectin-derived oligosaccharides, with functional or nutritional interesting properties.

Analogues of glycolipids from Spingomonadacaece with O- and S- and SO2-linkages have been prepared using chelation induced anomerisation promoted by TiCl4. Included are examples of the anomerisation of intermediates with O- and S-glycosidic linkages as well as isomerisation of beta-thioglycuronic acids (beta-glycosyl thiols). The beta-O-glucuronide and beta-O-galacturonide precursors were efficiently prepared using benzoylated trichloroacetimidates. beta-Glycosyl thiols were precursors to beta-S-derivatives. Triazole containing mimics of the natural glycolipids were prepared using CuI promoted azide-alkyne cycloaddition reactions in THF. The glycolipid antigens are being evaluated currently for their effects on iNKT cells.

The polyphenolic composition and antioxidant properties of the methanol leaf extract of Vitis × labruscana cv. 'Isabella' has been performed by means of different spectrophotometric antioxidant methods. Intracellular ROS produc- tion was measured by cell fluorescence after loading with 2',7'-H2DCF-DA. The extract promising efficacy has laid the basis to its phytochemical characterization. Three hydroxycinnamoyl tartaric acids (1-3), isoquercitrin 4, and five flavonol glycuronides (5-9) were isolated from Vitis × labruscana cv. 'Isabella' leaves. Chemical structures were elucidated on the basis of their spectroscopic features. Metabolites 6, 7, and 9, characterized by glucuronic or galacturonic acid methyl es- ter, are described from the genus Vitis for the first time. The metabolites isolated as major constituents were investigated for their DPPH radical scavenging capacity.

Structure, histochemistry and chemical composition of tension (TW), opposite (OW) and normal wood (NW) of Leucaena leucocephala have been studied using histological, histochemical and biochemical methods. TW vessels are longer and have a larger diameter than NW vessels, and the rays are shorter and thinner. The G-layer replaced S3 and parts of S2 wall layers in TW fibres. TW further contained less lignin that also had a lower syringyl-to-guaiacyl ratio. The lignin was also more condensed. The content of α-cellulose was high in TW. TW contains hemicelluloses and pectins composed of more galactose, and less xylose, mannose, 4-O-methylglucuronic acid and galacturonic acid compared to that of OW. This study suggests that in the TW of Leucaena, the amount and composition of lignin, hemicelluloses and pectins differ considerably from that in OW and NW.

The concept of nanoengineering of linen textile materials, realizing spatially localized effects of protein catalysts on polymeric cellulose companions and securing selective splitting of impurity compounds with preservation of technologically valuable nanoformations of binders in the fiber structure, is presented. The regulated degree of conversion of polysaccharides with the use of degradation products as secondary reagents for chemical transformations of lignin and polyphenolic compounds leads to the production of materials with new or improved functional and consumer properties.

A polysaccharide with [α]D –40.1° and MW 56,000 that consisted of L-arabinose, D-galactose, and galacturonic acid was obtained for the first time from the aerial part of Cardaria repens. It was found that the polysaccharide was a branched arabinogalactan where the main chain was 1,6-β-D-galactan and several galactose units were substituted by 1,3-α-Araf and 1,2-α-D-GalUA units.

An acidic polysaccharide was obtained from Psychrobacter maritimus 3pS isolated from a Siberian cryopeg sample (Kolyma lowland). The following structure of the tetrasaccharide repeating unit of the polysaccharide was established by sugar analysis along with 1 H and 13 C NMR spectroscopy: →2)-α- l -Rha p -(1→4)-α- d -Gal p NAcA-(1→3)-α- d -Qui p NAc4NHb-(1→3)-β- d -Qui p NAc4NHb-(1→ where d -GalNAcA indicates 2-acetamido-2-deoxy- d -galacturonic acid and d -QuiNAc4NHb indicates 2-acetamido-2,4,6-trideoxy-4-[( S )-3-hydroxybutanoyl]amino- d -glucose.

Monomode microwave-assisted syntheses of d-glucuronic and d-galacturonic acid derivatives are reported in the presence of a solid acid catalyst, consisting of sulfuric acid loaded onto silica. This approach affords a variety of surface-active monoglycosylated glucofuranosidurono-6,3-lactones and disubstituted galacturonic adducts in excellent yields in less than 10 min at 85°C. This study illustrates the application of microwave heating mode, in combination with a cost-effective solid catalyst, as an efficient, selective, and eco-friendly methodology in carbohydrate chemistry.

Concentration and temperature dependences of the redox potentials of neutral and alkaline solutions of glucose, mannose, galactose, galacturonic acid, and xylose were measured. Axial orientation of the secondary hydroxy groups in epimeric hexopyranoses, oxidation of C6 to carboxy group, and the lack of primary hydroxy group in going to aldopentopyranose favor increasing (in the order of listing) destabilization of their cyclic structure, formation of the oxo form, and thermally activated retro-aldol reaction of the latter in alkaline medium. This leads to enhancement of their reducing power and chemical reactivity toward 5,5′,7,7′-tetrabromoindigo.

The purpose of this study was to develop a poly(galacturonic acid) (PGA)-based hydrogel using a short-chain hyaluronate (sHA) cross-linker for medical applications. PGA was grafted with adipic acid dihydrazide (ADH) to yield PGA–ADH, an amine-containing PGA derivative. This PGA–ADH formed a water-insoluble hydrogel by reacting with 1,1′-carbonyldiimidazole (CDI)–grafted sHA (sHA–CDI) in aqueous solution. The sHA–cross-linked PGA hydrogel has a water content of about 94%–97% and compressive modulus of 10.7–26.9 kPa. The in vitro data indicated that the sHA–cross-linked PGA hydrogel is degradable and noncytotoxic, thus suitable for biomedical applications. Animal implant studies showed that the sHA–cross-linked PGA hydrogel membrane exhibited antiadhesion potency, significantly higher than that found in untreated rats and has great potential for future clinical applications.

Organic acids (oxalic, citric, galacturonic, tartaric, malic, lactic and succinic) contents of Gemlik variety olive fruits from five different cultivation areas of South Anatolia (Turkey), harvested in six collection dates (September, October and November of crop years 2006 and 2007), were determined by HPLC/DAD. Citric acid was the major compound (∼45%), followed by succinic (19%) and galacturonic acids (∼16%). The olive fruits of Antalya location showed the lowest and Karaman, Alanya and Hatay locations had the highest levels of total organic acids, especially on the early and late harvest. Significant interactions between “location”, “harvest date” and “crop year” were found, regarding the concentrations of citric, lactic, oxalic, tartaric and malic acid (3-way and 2-way interactions), which means that the effect of one factor (e.g. “location”) on an acid's concentration is not constant across the levels of the other factor. For succinic and galacturonic acids's concentrations, all interactions between the considered factors were statistically significant, except the 2-way interaction between “harvest date” and “crop year” which was no significant, meaning that the effect of factor “harvest date” on the succinic and/or on the galacturonic acid's concentrations does not vary significantly from one level of factor “crop year” to other. Significant mean differences were found in the concentrations of individual organic acids according to harvest time, which indicated generally a decline as harvest date moved on or no significant changes in some cases. Our results showed that rainfall and altitude of the location seemed to have more marked effects than temperature, on the levels of some organic acids such as malic, oxalic and succinic acids. The grouping of locations formed in Principal Component Analysis were quite different according to crop years, as for the first crop year (2006) “oxalic, citric, tartaric and succinic” and “lactic, malic, galacturonic” acids were the two groups of variables mainly responsible for discrimination, while for the following crop year (2007) “galacturonic, tartaric, oxalic, lactic”; “succinic, citric” and “malic” acids were the three groups responsible for the formation of clusters.

Uronic acids are carbohydrates present in relevant biologically active compounds. Most of the latter are glycosides or oligosaccharides linked by their anomeric carbon, so their synthesis requires glycoside-bond formation. The activation of this anomeric center remains difficult due to the presence of the electron-withdrawing C-5 carboxylic group. Herein we present an overview of glucuronidation, mannuronidation and galacturonidation reactions, including syntheses of prodrugs, oligosaccharides and stereochemical aspects.

Temperature-dependent formation of gelatin−poly(galacturonic acid) (PGA) multilayer films based on the layer-by-layer approach and their stability to changes in temperature, pH, and NaCl concentrat...

Allantoin is a heterocyclic organic compound. Allantoin ascorbate, allantoin biotin, allantoin galacturonic acid, allantoin glycyrrhetinic acid, allantoin panthenol, and allantoin polygalacturonic acid are complexes of allantoin. All of the ingredients in this review act as skin-conditioning agents. Allantoin was reported to be used in 1376 cosmetic products at concentrations up to 2%. There are data gaps regarding use and concentration of the remaining allantoin complexes. Ascorbic acid, biotin, glycyrrhetinic acid, and panthenol have been determined by the CIR Expert Panel to be safe. Galacturonic acid and polygalacturonic acid have not been reviewed by the CIR Expert Panel, and substantial data on these chemicals were not available. The safety test data in this safety assessment and in previous safety assessments were considered sufficient to support the safety of allantoin and the allantoin complexes in product categories and at concentrations reviewed in this safety assessment.