Galacturonic Acid Content Research Articles

Polystyrene-divinylbenzene-glycidyl methacrylate stationary phase grafted with poly (amidoamine) dendrimers for ion chromatography

In this work, a novel ion exchange stationary phase based on different generations of poly (amidoamine) dendrimers (PAMAM) was developed for the determination of inorganic anions and carbohydrates. Synthesis of the PAMAM was carried out with the polymerization reaction of ethylenediamine and methyl acrylate. The synthesized PAMAM was then grafted to the polystyrene-divinylbenzene-glycidyl methacrylate (PS-GMA) to form PAMAM-based beads. These beads were finally modified with 1,4-butanediol diglycidyl ether (BDDE) to generate the anion exchanger, which were characterized by scanning electron microscopy (SEM), brunauer-emmett-teller (BET), fourier transform infrared spectroscopy (FTIR), and elemental analysis. Elemental analysis, breakthrough curves and capacity factors showed that more epoxy groups and higher PAMAM generations in stationary phase could result in higher anion exchange capacity. The efficiency, durability and stability of the proposed anion exchanger were investigated by using six inorganic anions (fluoride, chloride, nitrite, bromide, nitrate and sulfate) and four carbohydrates (trehalose, glucose, maltotriose and galacturonic acid) as analytes, respectively. The reliability of the proposed ion chromatographic stationary phase was demonstrated by determining the content of galacturonic acid in polysaccharides from Poria cocos and Atractylodes macrocephala. The relative standard deviations of retention time, peak height, and peak area for galacturonic acid were 0.39%, 1.22%, and 2.02%, respectively. The spiked recoveries were in the range of 88.29%–100.51% for plant polysaccharides. Due to the good structural homogeneity, intense internal porosity, biological compatibility and high density of active groups in PAMAM, this grafted stationary phase showed good ion-exchange characteristics, especially in biological charged molecules.

А new factor effecting gel strength of pectin polysaccharides

Pectin polysaccharides obtained from various raw materials have a different component composition and form gels with water, sugar and acid or calcium. In this study, an experimental approach the gelation properties of different pectin samples, varied from different sources, using new methods of hydrolysis and purification. Samples were obtained by hydrolysis of accelerated extraction of pectin and purified by diaultrfiltration, have a high gel strength. The highest gel strength have been found in series of high methoxyl (HM-) pectin samples of apple, peach, orange and low methoxyl (LM-) pectin samples of commercial citrus pectin and apple pectin obtained by new method. It is shown that in addition to the basic parameters (the content of galacturonic acid, degree of esterification, molecular weight and hidrodinamic radius macromolecule) to affect gel strength pectins aggregation of macromolecules, which is determined by the z-average molecular weight. There were observed a clear pattern of the influence of the molecular weight on hydrodynamic parameters for both HM- and LM- pectin samples on the gel strength. It were shown that a high values of molecular weight, intrinsic viscosity, and radius of gyration of pectin samples can significantly increase gel strength, while the value of Mz oppositely influenced the gel strength. As a result, a systematic analysis of this parameter and its relationship to the average molecular weight found that indeed the ratio Mz/Mw for pectin’s is an crucial to assess the quality of pectin at the study of gel strength for pectin polysaccharides.

Pectin extraction from pomegranate peels with citric acid

Pectins were extracted from pomegranate peels with citric acid, according to a central composite design with three variables: pH (2–4), temperature (70–90°C), and extraction time (40–150min). Fourier transform infrared (FTIR) spectroscopy was used to follow changes in material composition during the main steps of pectin extraction, and also to determine the degree of methyl esterification and galacturonic acid content of pectins produced under different conditions. Harsh conditions enhanced the extraction yield and the galacturonic acid contents, but decreased the degree of methoxylation. The optimum extraction conditions, defined as those predicted to result in a yield of galacturonic acid higher than 8g/100g while keeping a minimum degree of methoxylation of 54% were: 88°C, 120min, pH 2.5. Close agreement was found between experimental and predicted values at the extraction conditions defined as optimum.

Extraction of pectin from passion fruit peel assisted by ultrasound

The effect of power intensity of ultrasound and temperature on the pectin extraction from passion fruit peel was evaluated by response surface methodology. The extraction was performed using a dried peel/extractant ratio fixed at 1:30 for 10 min of sonication. The dependent variables were the yield, the galacturonic acid content and the esterification degree of the extracted pectin. The highest yield of pectin was obtained by power intensity of 644 W/cm2 and temperature of 85 °C. Under these conditions, the yield, the galacturonic acid content and the esterification degree were 12.67%, 66.65% and 60.36%, respectively. The conventional extraction (dried peel/extractant ratio 1:30, 10 min and 85 °C) was performed to compare the results to the ultrasound-assisted extraction. The results showed that the use of ultrasound promoted a better extraction yield of pectin when compared to the conventional method.

Effect of extraction conditions on the antioxidant and antiglycation capacity of carbohydrates from Opuntia robusta cladodes

SummaryThe extraction and characterisation of six crude polysaccharides from Opuntia robusta cladodes, as well as the assessment of their antioxidant and antiglycation activities in vitro, were examined. In this work, carbohydrates were extracted from defatted cladode's peels and pulps through a sequential extraction method in different aqueous medium (neutral, basic and chelating). The obtained polysaccharides were compared in terms of yield and physicochemical properties. Water‐soluble extracts showed the highest yield, while peel's chelating‐soluble extract gave high galacturonic acid content. Preliminary antioxidant in vitro tests suggested that peel's chelating‐soluble extract presented the highest scavenging activity towards DPPH free radicals and inhibition of linoleic acid peroxidation. Furthermore, all extracted polysaccharides showed good potential in inhibiting the nonenzymatic glycation reaction, particularly on the first 3 days of incubation. The obtained results suggested that Opuntia robusta extracts could be explored as natural antioxidant, especially those extracted with chelating agent.

Enzymatic added extraction and clarification of fruit juices–A review

ABSTRACTEnzymatic treatment for juice extraction is most commonly used now a days. The enzymatic process is claimed to offer a number of advantages over mechanical-thermal comminution of several fruit pulps. Enzymes are an integral component of modern fruit juice manufacturing and are highly suitable for optimizing processes. Their main purposes are: increase extraction of juice from raw material, increase processing efficiency (pressing, solid settling or removal), and generate a final product that is clear and visually attractive. Juice extraction can be done by using various mechanical processes, which may be achieved through diffusion extraction, decanter centrifuge, screw type juice extractor, fruit pulper and by different types of presses. Enzymatic treatment prior to mechanical extraction significantly improves juice recovery compared to any other extraction process. Enzymatic hydrolysis of the cell walls increases the extraction yield, reducing sugars, soluble dry matter content and galacturonic acid content and titrable acidity of the products. Enzymatic degradation of the biomaterial depends upon the type of enzyme, incubation time, incubation temperature, enzyme concentration, agitation, pH and use of different enzyme combinations. We can conclude from the technical literature that use of the enzymes i.e. cellulases, pectinases, amylases and combination of these enzymes can give better juice yield with superior quality of the fruit juice. Pectinase enzyme can give maximum juice yield i.e. 92.4% at 360 minutes incubation time, 37°C incubation temperature and 5 mg/100 g of enzyme concentration. Whereas the combination of two enzymes i.e. pectin methyl esterase (PME) and polygalacturonase (PG) at 120 minutes of incubation time, 50°C of incubation temperature and 0.05 mg/100 gm of enzymatic concentration can give the maximum yield of 96.8% for plum fruits. This paper discusses the use of enzymes in fruit juice production focusing on the juice recovery, clarity and effect of the particular enzyme on the biochemical properties of the fruit juices.

Optimization of microwave assisted extraction of pectin from sour orange peel and its physicochemical properties

Microwave assisted extraction technique was used to extract pectin from sour orange peel. Box–Behnken design was used to study the effect of irradiation time, microwave power and pH on the yield and degree of esterification (DE) of pectin. The results showed that the optimum conditions for the highest yield of pectin (29.1%) were obtained at pH of 1.50, microwave power of 700W, and irradiation time of 3min. DE values of pectin ranged from 1.7% to 37.5%, indicating that the obtained pectin was low in methoxyl. Under optimal conditions, the galacturonic acid content and emulsifying activity were 71.0±0.8% and 40.7%, respectively. In addition, the emulsion stability value ranged from 72.1% to 83.4%. Viscosity measurement revealed that the solutions of pectin at low concentrations showed nearly Newtonian flow behavior, and as the concentration increased, pseudoplastic flow became dominant.

Aqueous extraction of pectin from sour orange peel and its preliminary physicochemical properties

Sour orange peel, a by-product of the fruit juice industry, was used as a source of pectin. The effects of temperature (75–95°C), time (30–90min), and liquid–solid ratio (20–40, v/w) were investigated on yield, methoxylation degree (DE), and galacturonic acid content using a Box–Behnken design and response surface methodology. The highest extraction yield (17.95±0.3%) was obtained at temperature of 95°C, time of 90min, and liquid–solid ratio of 25 (v/w). The DE values for the pectin ranged from 17% to 30.5%, indicating that the pectin was low in methoxyle. The emulsifying activity of pectin extracted under optimal conditions was 45%. The emulsions were 86.6% stable at 4°C and 71.4% at 23°C after 30 days of storage. The pectin exhibited Newtonian flow at low concentrations (≤1.0%, w/v); as the concentration increased, pseudoplastic flow became dominant.

The stiffening of the cell walls observed during physiological softening of pears.

Main conclusionThe Young’s modulus of the primary cell walls of pears decreases linearly during the pre-harvest on-tree maturation and increases during postharvest storage, and does not correlate with firmness of fruit.The determination of mechanical properties of cell walls is indispensable for understanding the mechanism of physiological softening and deterioration of quality of fruits during postharvest storage. The Young’s modulus of the primary cell walls from pear fruit (Pyrus communis L., cultivars ‘Conference’ and ‘Xenia’) during pre-harvest maturation and postharvest storage in an ambient atmosphere at 2 °C followed by shelf life was studied using atomic force microscopy (AFM). The results were related to the firmness of fruits, galacturonic acid content in water, chelator, sodium carbonate and insoluble pectin fractions, polygalacturonase and pectin methylesterase activities. The Young’s modulus of the primary cell walls decreased linearly during the last month of pre-harvest maturation from 3.2 ± 1.8 to 1.1 ± 0.7 MPa for ‘Conference’ and from 1.9 ± 1.2 to 0.2 ± 0.1 MPa for ‘Xenia’ which correlated with linear firmness decrease. During postharvest storage the cell wall Young’s modulus increased while firmness continued to decrease. Correlation analysis for the entire period of the experiment showed a lack of straightforward relation between the Young’s modulus of primary cell walls and fruit firmness. The Young’s modulus of cell walls correlated negatively either with galacturonic acid content in sodium carbonate soluble pectin (‘Conference’) or with insoluble pectin fractions (‘Xenia’) and positively with polygalacturonase activity. It was therefore evidenced that covalently linked pectins play the key role for the stiffness of fruit cell walls. Based on the obtained results, the model explaining the fruit transition from firm and crispy to soft and mealy was proposed.Electronic supplementary materialThe online version of this article (doi:10.1007/s00425-015-2423-0) contains supplementary material, which is available to authorized users.

Optimization of pectin extraction from banana peels with citric acid by using response surface methodology

A central composite design was used to determine effects of pH (2.0–4.5), extraction temperature (70–90°C) and time (120–240min) on the yield, degree of methoxylation (DM) and galacturonic acid content (GA) of pectins extracted from banana peels with citric acid. Changes in composition during the main steps of pectin extraction were followed by Fourier transform infrared (FTIR) spectroscopy. FTIR was also used to determine DM and GA of pectins. Harsh temperature and pH conditions enhanced the extraction yield, but decreased DM. GA presented a maximum value at 83°C, 190min, and pH 2.7. The yield of galacturonic acid (YGA), which took into account both the extraction yield and the pectin purity, was improved by higher temperature and lower pH values. The optimum extraction conditions, defined as those resulting in a maximum YGA while keeping DM at a minimum of 51%, were: 87°C, 160min, pH 2.0.

Optimization of fermentation conditions of pectin production from Aspergillus terreus and its partial characterization

Figures of persimmons for the world's top ten persimmon producing countries are about 4000,000 tons in 2011 and are increasing every year according to FAO statistics. However, there is not any report on pectin production by microbial with persimmon peel as the source. Optimization of fermentation conditions of pectin production from Aspergillus terreus in submerged culture and partial characterization of pectin were carried out in the work. An optimum fermentation condition for pectin production was obtained through a central composite rotatable design in response surface methodology as follows: fermentation time, 30.09h, temperature, 25.00°C and the initial pH in the fermentation medium, 6.90, respectively and the pectin yield reached the maximal value 0.449g/g. Persimmon peel pectin had highly methoxylated (62.51%), high galacturonic acid content (82.28%) than citrus pectin, and was classified as the highly methoxylated pectin, the results indicated that persimmon peel had potential good resources for pectin production. The investigation can make it available to utilize persimmon peel to produce high methoxyl pectin for food industry, pharmacy and cosmetic manufacture.

Application of Celluclast 1.5L in apple pectin extraction

Pectins were extracted from apple pomace with Celluclast 1.5L at a dose of 25, 50 and 75μl per 1g of material. In obtained pectin, the galacturonic acid (GalA) content, the neutral sugars (NS) profile, the degree of methylation (DM) and acetylation (DAc), the molecular mass, protein, ash and polyphenol levels as well as antioxidant and antitumor activity were determined. The lowest dose of enzymatic preparation resulted in the yield of pectin isolation comparable with acidic treatment (15.3%). Application of higher dose caused further, almost 4% increase in polymer recovery. Enzymatically isolated pectin was characterised by larger molecular mass and contained more GalA of higher DM and DAc than polymer extracted with acid. It was also richer in protein and polyphenols, and had different NS profile, which resulted in higher antiradical activity as well as the ability to inhibit the proliferation and invasion of Caco-2 adenocarcinoma cells.

Extraction and Characterization of Fibres from the Stalk and Spikelets of Empty Fruit Bunch

Fibres from different parts of empty fruit bunch, which is a major solid waste from oil palm processing, were subjected to different pretreatments and characterised for variability in length and diameter, mechanical performance, and proximate and trace element composition. Morphology and surface composition of the fibres were determined using scanning electron microscopy with energy dispersive X-ray. The fibres were further treated with KOH-boric acid and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Fibre yield was higher for spikelet than stalk. Fibres from stalk were generally larger in diameter and showed significant differences in potassium and galacturonic acid content, strength, and rigidity. Scanning electron microscopy confirmed the widespread occurrence of silica bodies as well as significant differences in the microstructure of stalk and spikelet fibres. Stalk fibres showed a greater level of porosity than spikelet fibres in the section perpendicular to the major axis. The morphology of KOH-boric acid treated fibres suggested higher recalcitrance of spikelet fibres. The significant differences between fibres from stalk and spikelet suggest that EFB, used as feedstock for biobased industries, requires more systematic characterization and separation into stalk and spikelet, which may lead to a more judicious exploitation of this valuable waste.

Mango pectin quality as influenced by cultivar, ripeness, peel particle size, blanching, drying, and irradiation

Industrial recovery and application of valuable mango (Mangifera indica L.) peel constituents, such as dietary fiber and pectins, require the conversion of the yet under-utilized and highly perishable by-product into a stable commodity. Focusing on efficient pectin recovery, the impact of different cultivars and ripeness degrees as well as various technological procedures on pectin quality by affecting pectin yield, molecular size distribution of pectic polymers, galacturonic acid content, degree of esterification, and content of interfering substances was analyzed. Cultivar and ripeness degree revealed a significant effect on pectin quality. Preservation processes, i.e. oven drying and lyophilization each with and without previous blanching of integral fruits as well as gamma irradiation, notably influenced the quality of the obtained pectin. Blanching prior to drying reduced arabinogalactan and ash impurities, whereas galacturonic acid contents were increased. Most importantly, grinding of dried mango peels to obtain a particle size of ca. 42 μm (d43) significantly enhanced both extraction yield (+70%) and galacturonic acid content (+20%) without increasing the contents of the above mentioned impurities as compared to a peel particle size of ≥10 mm. Mango pectin produced from such peel powders with a small particle size (≤120 μm) improved breaking and sugar binding capacities as well as gelling units (up to 5476 GU). The production of mango peel pectin and its applications were favored by implementing the proposed procedures into the valorization cascade of mango peels.

Purifying sugar beet pectins from non-pectic components by means of metal precipitation

Metal precipitation is an effective method for the purification of pectins. To study the selectivity of copper ions toward binding pectic or non-pectic compounds, two fractions, namely copper-precipitated pectins (CPP) and copper-unprecipitated pectins (CUP) were fractionated from the mother sugar beet pectins by means of copper precipitation. Comparison on chemical feature revealed the isolated fractions were structurally different in that CUP contained markedly higher neutral sugars (NS) and protein contents, but lower galacturonic acid and acetyl ester group contents than CPP. However, no appreciable difference was observed in terms of degree of methylation (DM). Elution profiles on high performance size exclusion chromatograph showed that CPP exhibited a monomodal-like molecular weight distribution (MWD), while CUP demonstrated a multimodal-like MWD pattern composed of three relatively broad peaks, and a narrow peak that was associated with a high intensity of UV signal at 278 nm. Moreover, AFM analysis showed that CPP displayed branched fibrous structures, while CUP showed distinguishable granular-like shapes. Results obtained in this work indicate the employed copper ions selectively bind the anionic regions among pectin chains, thereby separating pectic saccharides from non-uronide compounds, i.e. low molecular weight carbohydrates and free proteins. The poor affinity of copper ions toward CUP might be determined by the absence of typical homogalacturonan (HG) regions.

Effect of storage conditions on pectic polysaccharides in common beans (Phaseolus vulgaris) in relation to the hard-to-cook defect

The importance of common beans (Phaseolus vulgaris) in addressing food insecurity cannot be underestimated. However, their utilization is hampered by development of the hard-to-cook (HTC) defect, i.e., the inability of cotyledons to soften sufficiently within a reasonable time during cooking, the presence of flatulence causing oligosaccharides, the antinutrients and the low digestibility of macronutrients. The objective of this study was to determine the effect of storage conditions (time, temperature and relative humidity) on pectic polysaccharides of selected common bean varieties during the evolution of the hard cook problem. First, alcohol insoluble residue (AIR) was extracted from the bean flour. The AIR was fractionated into water, chelator and Na2CO3-soluble pectin fractions and a hemicellulose fraction. The galacturonic acid content, neutral sugars, degree of methylesterfication (DM), degree of acetylation (DAc) and molar mass distribution for pectin fractions were determined. In addition, filterable residual protein in various fractions was estimated. Results on the acidic and neutral sugars revealed that common beans contained highly branched, arabinose-rich pectic polysaccharides. Storage of common beans for more than 4months at high relative humidity (83%) and high temperature (45°C) resulting in HTC development showed a decrease in pectin extractability in water paralleled by an increase in the alkaline-soluble fraction. Other pectin characteristics such as DM and DAc showed minor variations upon storage of beans. The hydrolysis of both starch and proteins before AIR extraction decreased with increasing storage time, temperature and relative humidity. The increase in residual starch and protein might be linked to the protein–starch hypothesis where predominance of protein denaturation leads to restricted starch gelatinization. The results reveal that the contribution of pectic polysaccharides to development of HTC defect during the storage of Canadian wonder and Red haricot common beans at elevated temperature and relative humidity is due to reduced pectin solubility. However, the influence of starch and proteins seems evident.

Extraction of pectin from passion fruit peel using moderate electric field and conventional heating extraction methods

Abstract Yellow passion fruit peel contains a high level of pectin that can be extracted from cell walls of plants. Direct boiling is a conventional method of extraction, which takes around 2 h to obtain a good yield of pectin. The long period of heating can produce degradation in the pectin, when the conventional heating is used to extract the pectin a lot of time and energy is spent. The purpose of this study was to explore the conventional and the moderate electric field extractions of pectin from passion fruit peel. The comparison of galacturonic acid content and esterification degree of the pectin obtained by different extraction methods indicated that similar values were obtained. Furthermore, moderate electric field is an efficient, timesaving, and eco-friendly method for the extraction of pectin from passion fruit peel, especially for pectin with a high esterification degree and galacturonic acid content higher than 65%. Industrial relevance This information is important for food industry since direct boiling, that is a conventional method of extraction, takes around 2 h to obtain a good yield of pectin and uses strong acid solutions. Also, today, this information which shows much interest in the food industry.

The impact of rhamnogalacturonan-I side chain monosaccharides on the rheological properties of citrus pectin

Citrus peel is the preferred raw material for pectin production, mainly due to its high pectin content but also due to the gelling capabilities. Especially the high galacturonic acid content and the high degree of methyl esterification make it an attractive starting material for further modification. Until now the presence of rhamnogalacturonan-I (RG-I) in commercial pectin has received less attention due to its relatively low abundance. Using a gentle industrial extraction process we discovered a slightly higher composition in neutral sugars of RG-I. In particular, the arabinose concentration in mildly extracted pectin was higher compared to conventionally extracted pectin. The use of enzymes specific for either arabinan or galactan allowed assessing the implications of varying neutral sugar composition on the gelling capabilities of pectin. A comparison between untreated and debranched pectin revealed a significant decrease in both gelling temperature (up to 20 °C) and gel strength (up to 38%), following the specific reduction in neutral sugars concentration. Coil-overlap and entanglement effects were analysed to further understand the impact of RG-I side chains on polymer rheology.

Cell-wall polysaccharide composition and glycanase activity of Silene vulgaris callus transformed with rolB and rolC genes.

The aim of this research is to investigate the effects of the Agrobacterium rhizogenes rol genes on the composition of cell-wall polysaccharides and glycanase activity in the campion callus. The expression of the rolC gene reduces the yield of campion pectin, while the expression of the rolB or rolC gene inhibits the volumetric production of both pectin and intracellular arabinogalactan. The rol genes are involved in regulating the activity of glycanases and esterases, thereby contributing to the modification of polysaccharide structures, their molecular weight (Mw) and the degree of pectin methyl esterification (DE). The increase in pectin arabinose residue appears to be connected to a decrease in intracellular and extracellular α-l-arabinofuranosidase activity in transgenic campion calluses. In transgenic calluses expressing the rolB and rolC genes, the increase in pectin galactose residue is likely due to a decrease in β-galactosidase activity. The decrease in the Mw of pectin and its d-galacturonic acid content appears to be connected to an increase in extracellular polygalacturonase activity. Finally, the increase in pectinesterase activity causes a decrease in the DE of pectin. Thus, the expression of rolB and rolC genes in campion callus has a considerable effect on pectin's sugar composition, DE and Mw, while it appears to have an insignificant influence on intracellular and extracellular arabinogalactans.

A new approach for pectin extraction: Electromagnetic induction heating

Electromagnetic induction (EMI) and conventional (CV) heating have been employed to extract pectin from citrange (Citrus sinensis×Poncirus trifoliata) albedos under the same extraction conditions (pH 1.2, temperature 80°C and extraction time 90min). The electromagnetic induction heating process was investigated at different extraction times (10, 20, 30, 40, 50, 60 and 90min) and at different power levels. The high pectin yield obtained with this process was found to be 29% (w/w) of dried albedos, which was almost equal to that found using conventional heating (24% (w/w)). However, a considerable reduction in the extraction time was observed. It was found that 30min of electromagnetic induction extraction of pectin from dried albedos yielded the same amount (24% (w/w)) of pectin obtained by conventional heating process for 90min. Also, the electromagnetic induction heating at higher power and for only 2.09min gave half the amount of pectin extracted by conventional heating for 90min. Moreover, it was found that both extracted pectins showed almost similar compositions and physicochemical properties, presenting a galacturonic acid content of 29.10–29.40% and an esterification degree of 61.00–62.50%. The average molecular weight for both pectins extracted by EMI and CV heating ranged from 0.84×105 to 1.63×105. Hence, the electromagnetic induction heating can be suggested as a promising method for the extraction of pectin from citrange albedos at a short time, with a remarkable yield and keeping the composition and the physicochemical properties of the pectin unchanged.