High Galacturonic Acid Content Research Articles

Investigation of the Structural Properties and Antioxidant Potency of Pectic Polysaccharides Derived from Rohdea japonica (Thunb.) Roth.

This study investigated the structural composition and antioxidant properties of pectic polysaccharides extracted from Rohdea japonica (Thunb.) Roth. Pectins, which belong to a complex category of acidic polysaccharides, possess a wide range of biological effects stemming from their distinctive structural domains. The polysaccharides were extracted using water, and were subsequently purified through ion exchange and gel permeation chromatography. In order to elucidate their structural features, Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance techniques were applied. Two specific polysaccharides, WRJP-A2a and WRJP-A3b, with molecular weights of 42.7 kDa and 64.1 kDa, respectively, were identified to contain varying proportions of homogalacturonan, rhamnogalacturonan I, and rhamnogalacturonan II domains. Regarding antioxidant capacity, WRJP-A3b exhibited superior scavenging capabilities against DPPH, ABTS, and hydroxyl radicals, potentially attributed to its higher galacturonic acid content and abundance of homogalacturonan domains. These results enhance our comprehension of the structure-activity interplay of pectic polysaccharides sourced from Rohdea japonica (Thunb.) Roth and their potential utility in the healthcare and functional food sectors.

Physicochemical, structural and functional properties of pomelo peel pectin extracted by combination of pulsed electric field and cellulase hydrolysis

In this study, pectin extracted from pomelo peel was investigated using three different combination methods of pulsed electric field (PEF) and cellulase. Three action sequences were performed, including PEF treatment followed by enzymatic hydrolysis, enzymatic hydrolysis followed by PEF treatment, and enzymatic hydrolysis simultaneously treated by PEF. The three corresponding pectins were namely PEP, EPP and SP. The physiochemical, molecular structural and functional properties of the three pectins were determined. The results showed that PEP had excellent physiochemical properties, with the highest yield (12.08 %), total sugar (80.17 %) and total phenol content (38.20 %). The monosaccharide composition and FT-IR analysis indicated that the three pectins were similar. The molecular weights of PEP, EPP and SP were 51.13, 88.51 and 40.00 kDa, respectively. PEP showed the best gel properties, emulsification stability and antioxidant capacity among the three products, due to its high galacturonic acid and total phenol content, appropriate protein and low molecular weight. The mechanism of PEF-assisted cellulase hydrolysis of pomelo peel was also revealed by SEM analysis. These results suggested that PEF pretreatment was the best method, which not only improved the efficiency of enzymatic extraction, but also reduced resource waste and increased financial benefits.

Effect of Organic Acid-Aided Extraction on Characteristics and Functional Properties of Pectin from Cannabis sativa L.

The extraction of cannabinoids from the inflorescence and leaves of Cannabis sativa L. is gaining interest from researchers, in addition to addressing the under-utilization of the by-products in the stems and roots of the trees. The present study investigated the recovery of pectin from the left-over parts of hemp tress using an eco-friendly method with the aid of organic acids. Different cannabis cultivars-Chalotte's Angels (CHA) and Hang-Krarog (HKR)-were used as plant materials. The stems of both cannabis cultivars contained more pectin than the roots, and tartaric acid-aided extraction provided higher yields than from citric acid. Extracting the acid solution affected some characteristics, thereby differentiating the functional properties of the derived pectin. Extraction using tartaric acid provided pectin with a higher galacturonic acid content, whereas pectin with a higher methylation degree could be prepared using citric acid. The pectin samples extracted from the stems of CHA (P-CHA) and HKR (P-HKR) had low methoxyl pectin. P-CHA had better free radical scavenging capability, whereas P-HKR showed more potent reducibility. Considering the functional properties, P-CHA showed greater emulsion formability and foaming activity, whereas P-HKR possessed a better thickening effect. The present work suggests the feasible utilization of P-CHA and P-HKR as food additives with bioactivity.

Green Extraction of Pectin from Sugar Beet Flakes and Its Application in Hydrogels and Cryogels.

Sugar beet flakes, a by-product of the sugar industry, were used as a source for pectin extraction that was performed using conventional citric acid extraction (CE) and two non-conventional extraction techniques-microwave-assisted extraction (MAE) and pulsed ultrasound-assisted extraction (PUAE). The influence of extraction conditions was studied for each technique based on pectin yield and galacturonic acid content, and spectroscopic, chromatographic and colorimetric methods were used for pectin characterization. Better results for pectin yield were achieved through CE (20.80%), while higher galacturonic acid content was measured in pectin extracted using PUAE (88.53 g/100 g). Pectin extracted using PUAE also presented a higher degree of methylation and acetylation. A significant increase in the molecular weight of pectin was observed for the PUAE process (7.40 × 105 g/mol) by comparison with conventional extraction (1.18 × 105 g/mol). Hydrogels and cryogels prepared with pectin from sugar beet flakes also showed differences in physicochemical parameters determined by the method of pectin extraction. Hydrogels had higher bulk density values irrespective of the pectin extraction method, and overall lower values of the textural parameters. Cryogels prepared with pectin from CE showed higher values of the textural parameters of hardness, adhesiveness, cohesiveness, gumminess and chewiness, while gels obtained with pectin from MAE and PUAE had higher thermal stability. The results of this study prove that sugar beet flakes can be considered a potential source for pectin production, and the extracted pectin is suitable for obtaining hydrogels and cryogels with physicochemical parameters comparable to the commercial citrus and apple pectin available on the market.

Ultrasound-assisted extraction (UAE) and characterization of citrus peel pectin: Comparison between pummelo (Citrus grandis L. Osbeck) and sweet lime (Citrus limetta Risso)

Citrus peels are a commercial source for pectin extraction which is widely used in the food industry as a hydrocolloid, fat mimetic, and gelling agent. Acid extraction is an established method for extraction; however, environmental and consumer concerns are pushing processors to explore sustainable and green methods to provide clean solutions. The present study was designed to optimize pectin extraction from pummelo and sweet lime peels using ultrasound-assisted extraction (UAE). The optimized conditions of UAE obtained through response surface methodology (RSM) were: sonication time = 9.38 min, power = 44.01%, and liquid-solid ratio (L:S) of 46.8:1. These levels resulted in maximum pectin yield (26.35%) and high galacturonic acid content (69.11%; GalA) from pummelo peels as compared to sweet lime peels. The pectin extracted via UAE was food-grade with a low degree of methylation (<50%) and high functional quality. Characterization of pectin through Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and rheology confirmed its similarity to commercial pectin. Pummelo peel pectin demonstrated high biological activity in inhibiting lipid deposition in HepG2 cells and low cytotoxicity in 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Overall, based on rheological and functional properties, pummelo peels were found to be superior to sweet lime for commercial pectin extraction. The findings suggest that citrus peel pectin with low degree of esterification (DE<50%) is a valuable ingredient for formulating low glycemic functional foods. Overall UAE seems to be an efficient, economic, and sustainable method for extraction of high-quality pectin.

Structural and physicochemical properties of subcritical water-extracted soy hull polysaccharides: Relationship to salty taste of sodium

The reduction of sodium intake without affecting saltiness perception is still a huge challenge. The acid method (pH 2.0, 85 °C, 90min) and subcritical water treatment (SW, pH 6.3–2.0, 120 °C, 30min) were used to prepare saltiness-enhanced polysaccharides from soy hull. Structural and physicochemical properties of soy hull polysaccharides (SHP) and their relationship to the salivary diffusion and mucosal retention of Na+ were analyzed. Compared to acid-extracted SHP (ASHP), SW-extracted SHP (SW6.3, SW5.0, and SW4.0) exhibited a higher saltiness-enhanced effect, accompanied by an accelerated diffusion of Na+ in the saliva and enhanced adhesive retention of Na+ on the porcine tongue. These phenomena may be attributed to different fractions extracted by two methods. ASHP mainly consists of pectic polysaccharides with a higher galacturonic acid content, while RG-I enriched pectic and hemicellulosic polysaccharides were speculated for SW6.3, SW5.0 and SW4.0, which exhibited highly branched conformation with higher Mw and lower charge. The SHP-induced disruption of the salivary mucin network probably accelerates the Na+ permeation and the adhesion of Na+ on the porcine tongue. SW3.0 and SW2.0 showed lower apparent viscosity and Mw due to excessive degradation of the backbone and side chain, weakening the diffusion and adhesion of Na+, and salt taste. These results would be useful to reveal the regulatory mechanism of polysaccharides on saltiness perception, which provided a technology to prepare a saltiness-enhanced ingredient from a by-product of soybean processing for low-sodium foods.

High-intensity pulsed electric field-assisted acidic extraction of pectin from citrus peel: Physicochemical characteristics and emulsifying properties

Sustainable innovation seeks more energy-efficient processes for producing highly demanded products from industrial by-products. This study follows this endeavor. Comparisons were made on two processes for producing pectins from citrus peel as well as the two derived pectin products: a high-intensity pulsed electric field (HIPEF) pretreatment of citrus peel powder followed by a milder acidic extraction (pH 2, heating at 70 °C for 1 h; pectin termed HIPEF-CP), and a conventional direct hot-acid extraction (pH 2, heating at 90 °C for 2 h; pectin termed CP). HIPEF-assisted extraction significantly improved pectin yield (by 8.48%) and production efficiency (by 100.23%) while reducing energy consumption. Both were low-methoxyl pectins with similar branching degrees and contents of rhamnogalacturonan-I (RG-I), protein, phenolic compounds, total alkaloids and vitamin C. Compared with CP, HIPEF-CP contained higher homogalacturonan content, higher galactose content, higher galacturonic acid content, lower arabinose content, lower xylose content, slightly lower degree of methyl esterification, higher linearity, lower side chain size, higher molecular weight, and wider molecular weight distribution. The antioxidant, emulsifying and emulsion-stabilizing abilities of HIPEF-CP were superior to those of CP, though both pectins were satisfactory emulsifiers, exhibiting good antioxidant activities and emulsifying capacities at pectin concentrations not lower than 1.0%. The HIPEF pretreatment of citrus peel made the subsequent acidic pectin extraction feasible under milder conditions, to produce pectin with desired antioxidant and emulsifying capacities.

Characterization and Applications of the Pectin Extracted from the Peel of Passiflora tripartita var. mollissima.

The inadequate management of organic waste and excessive use of plastic containers cause damage to the environment; therefore, different studies have been carried out to obtain new biomaterials from agricultural subproducts. The objective of this work was to evaluate the feasibility of using the pectin extracted from the peel of Passiflora tripartita var. mollissima (PT), characterizing its type and viability for the production of edible biodegradable films. In addition, films of two thicknesses (23.45 ± 3.02 µm and 53.34 ± 2.28 µm) were prepared. The results indicated that PT is an excellent raw material for the extraction of pectin, with high yields (23.02 ± 0.02%), high galacturonic acid content (65.43 ± 2.241%), neutral sugars (ribose, xylose, glucose) and a high degree of esterification (76.93 ± 1.65%), classifying it as a high-methoxy pectin. Regarding the films, they were malleable and flexible, with a water vapor permeability from 2.57 × 10-10 ± 0.046 to 0.13 × 10-10 ± 0.029 g/s mPa according to thickness, being similar to other Passiflora varieties of edible films. The pectin extraction yield from PT makes this fruit a promising material for pectin production and its chemical composition a valuable additive for the food and pharmaceutical industries.

A comparison study on structure-function relationship of polysaccharides obtained from sea buckthorn berries using different methods: antioxidant and bile acid-binding capacity

In this study, the structural characters, antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides (HRPs) obtained by the commonly used hot water (HRP-W), pressurized hot water (HRP-H), ultrasonic (HRP-U), acid (HRP-C) and alkali (HRP-A) assisted extraction methods were investigated. The results demonstrated that extraction methods had significant effects on extraction yield, monosaccharide composition, molecular weight, particle size, triple-helical structure, and surface morphology of HRPs except for the major linkage bands. Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability. The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities. Moreover, the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network (HRP-C, HRP-W and HRP-U), which exhibited stronger bile acid binding capacity. The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.

Changes in the structure of polysaccharides under different extraction methods

Changes in the structure of polysaccharides under different extraction methods

Physicochemical characterization, rheological and antioxidant properties of three alkali-extracted polysaccharides from mung bean skin

The properties of polysaccharides are closely related to their extraction and preparation methods. However, studies on the effect of alkali concentration on the properties of polysaccharides during alkali extraction are scarce. In this study, three alkali-extracted polysaccharides from mung bean skin (MBP) by different alkali concentrations (0.5%, 1.0%, 2.0%, w/v, MBP0.5, MBP1.0 and MBP2.0) were successfully obtained. The effects of alkali concentration on the extraction rate, microstructure, rheological properties, antioxidant activity and cell proliferation activity of MBP were investigated. The results showed that the alkali extraction method can break the ester and hydrogen bonds between polysaccharides, thus three alkali-extracted polysaccharides had higher extraction yields than polysaccharide extracted by hot water (MBPW), and MBP1.0 extraction rate of 3.64%. Moreover, comparing with MBPW, three alkali-extracted polysaccharides had lower molecular weights, particle sizes and better thermal stability. In addition, MBP0.5 had better antioxidant activity due to its higher galacturonic acid content and lower molecular weight, MBP1.0 and MBP2.0 had a tight structure, flat surface, resulting in a strong gel network structure. Cell experiments showed that MBPs had different degrees of proliferative effects on RAW264.7 and L-02. This study will provide some research ideas for the extraction of plant polysaccharides by alkaline methods.

Effect of Ultrasound-Assisted, Microwave-Assisted and Ultrasound-Microwave-Assisted Extraction on Pectin Extraction from Industrial Tomato Waste

This work aimed to study the effect of ultrasound-assisted (UAE), microwave-assisted (MAE), and ultrasound-microwave-assisted (UMAE) methods for pectin extraction from industrial tomato waste. The overall performance index from the fuzzy analytical method with three criteria, pectin yield, galacturonic acid, and lycopene content, was applied to evaluate the best extraction conditions by using the weight of 75, 20, and 5, respectively. The UAE conditions was performed at a temperature of 80 °C for 20 min with the variations in the extraction pH and the solid liquid (SL) ratio. The best UAE conditions with high pectin yield, and high total carboxyl group, as well as a lycopene content, was the pH of 1.5 and the SL ratio of 1:30. The MAE conditions was performed with variations in the microwave powers and times. The results showed that the best MAE conditions were 300 W for 10 min, which gave high pectin yield with high galacturonic acid and lycopene content. Various conditions of UMAE at the best conditions of MAE and UAE were performed and exhibited that the UAE had more positively affected the pectin yield. However, the FTIR spectra of obtained pectins from different extraction techniques showed a similar pectin structure.

Rheological and gelling properties of Nicandra physalodes (Linn.) Gaertn. pectin in acidic media

Nicandra physalodes (Linn.) Gaertn. polysaccharide (NPGP) was previously recognized as a pectic polysaccharide, with a high galacturonic acid content (87.8%) and a low methoxylation degree (28%). In the present study, it was found that NPGP can form self-supporting gels when cooling its heated solutions (2.0%, w/v) acidified by citric acid. It was demonstrated that the decrease in pH led to the suppression in electrostatic repulsions between the pectin chains, thereby promoting pectin chain-chain association mainly through hydrogen bonding. As the pH decreased from 3.2 to 2.4, the gel strength and gel thermal stability were continuously increased. Moreover, it was shown that sucrose addition slightly promoted the gelation and gel thermal stability of NPGP, but the effect of monovalent ions (Na+) and divalent ions (Ca2+) was not significant. Conclusively, our results indicate that NPGP is a new gelling polysaccharide that shows great potential in formulation of acidic gel foods.

Structure Characterization of Polysaccharide from Chinese Yam (Dioscorea opposite Thunb.) and Its Growth-Promoting Effects on Streptococcus thermophilus.

To clarify the mechanisms underlying the growth-promoting effects of yam polysaccharide on Streptococcus thermophilus (S. thermophilus), the yam polysaccharide was extracted using a deep eutectic solvents (DESs) method and separated into four fractions by DEAE-cellulose 52. These fractions were used as the alternative carbon source to substitute lactose to compare their growth-promoting effects on S. thermophilus. Furthermore, their molecular weight, monosaccharide and functional groups’ composition, microscopic forms and other basic structure characterizations were analyzed. The results showed that all the fractions could significantly promote S. thermophilus growth, and fractions exhibited significantly different growth-promoting effects, whose viable count increased by 6.14, 6.03, 11.48 and 11.29%, respectively, relative to those in the M17 broth medium. Structure-activity relationship analysis revealed that the high growth-promoting activity of yam polysaccharide might be more dependent on the higher molecular weight, the higher galacturonic acid content and its complex spatial configuration, and the existence of β-glycosides would make the yam polysaccharide have a better growth-promoting effect on S. thermophilus.

Microwave vs. conventional extraction of pectin from Malus domestica ‘Fălticeni’ pomace and its potential use in hydrocolloid-based films

Conventional extraction (CE) and microwave-assisted extraction (MAE) were compared in terms of efficiency and quality of pectin in two separate processes aimed to extract pectin from Malus domestica ‘Fălticeni’ apple pomace. A similar extraction yield in a shorter extraction time was observed for the microwave-assisted procedure as compared to CE, while the galacturonic acid content and the degree of esterification of pectin were similar for both methods. Apple pectin extracted from this plant source by both methods had high galacturonic acid content, degree of esterification and molecular weight. Considering the high efficiency of microwave-assisted extraction and the composition of the obtained pectin, microwave-assisted apple pectin extracted under optimal conditions was used to produce edible films in combination with hydroxypropyl methylcellulose (HPMC). Films formulated with pectin from microwave extraction had significant lower oxygen permeability as compared to plasticized pure HPMC films, which makes microwave extracted pectin suitable for film-forming applications in which a good barrier to oxygen is required.

Effects of different extraction methods on structural and physicochemical properties of pectins from finger citron pomace

The functionality and property of pectin are correlated with its structure which is affected by the extraction method used. In this study, three different methods of extracting pectin, the microwave-assisted extraction (MAE), the ultrasonic-assisted extraction (UAE) and the conventional heating extraction (CHE), were used at three different temperatures with both an acid and alkali extraction solution. It was found that temperature mainly influenced pectin yield, while pectin structures and physicochemical properties were affected by the pH condition and extraction technology. The alkali-extraction with MAE and UAE at short time promoted the yield of low-ester pectin. Monosaccharide composition analysis showed a high galacturonic acid (GalA) content in the pectin derived from MAE and UAE. The high viscosity and desirable viscoelastic properties of the acid-MAE pectin were due to its large molecular weight and particle size. The results contribute to our understanding of the association among pectin extraction, structure and properties.

Volarization of valuable compound from watermelon by-product using ultrasound-assisted extraction

The aim of this study was to develop an efficient, reliable, and sustainable technology for the recovery of value-added compounds from by-product, in this case, is watermelon rinds. The properties of the watermelon rinds obtained from innovative ultrasoundassisted extraction (UAE) were evaluated. In regard to this, the pectin content, degree of esterification, and galacturonic acid content of the watermelon rind extracts were determined in order to verify the efficiency of the UAE. Initially, the UAE were conducted using two types of acid: citric and hydrochloric. The highest pectin content was obtained using citric acid. Additional UAE was then performed with citric acid at 50, 60, or 70°C for 10, 20, or 30 mins. Both UAE temperature and time significantly influenced the pectin extracts and galacturonic acid. The best findings for a high galacturonic acid content (47.41%) when the watermelon rinds were extracts at 70°C for 20 mins. According to the findings, the extraction process lasted 10 or 20 mins at all temperatures was mainly high-methoxyl pectin, which can form gels under acidic conditions. This suggests that pectins derived from watermelon rinds using UAE may be especially useful as an additive in some confectionery products.

Isolation and Biophysical Characterisation of Bioactive Polysaccharides from Cucurbita Moschata (Butternut Squash).

Cucurbits are plants that have been used frequently as functional foods. This study includes the extraction, isolation, and characterisation of the mesocarp polysaccharide of Cucurbita moschata. The polysaccharide component was purified by gel filtration into three fractions (NJBTF1, NJBTF2, and NJBTF3) of different molecular weights. Characterisation includes the hydrodynamic properties, identification of monosaccharide composition, and bioactivity. Sedimentation velocity also indicated the presence of small amounts of additional discrete higher molecular weight components even after fractionation. Sedimentation equilibrium revealed respective weight average molecular weights of 90, 31, and 19 kDa, with the higher fractions (NJBTF1 and NJBTF2) indicating a tendency to self-associate. Based on the limited amount of data (combinations of 3 sets of viscosity and sedimentation data corresponding to the 3 fractions), HYDFIT indicates an extended, semi-flexible coil conformation. Of all the fractions obtained, NJBTF1 showed the highest bioactivity. All fractions contained galacturonic acid and variable amounts of neutral sugars. To probe further, the extent of glycosidic linkages in NJBTF1 was estimated using gas chromatography–mass spectrometry (GCMS), yielding a high galacturonic acid content (for pectin polysaccharide) and the presence of fructans—the first evidence of fructans (levan) in the mesocarp. Our understanding of the size and structural flexibility together with the high bioactivity suggests that the polysaccharide obtained from C. moschata has the potential to be developed into a therapeutic agent.

Comparison of structural characterization and antioxidant activity of polysaccharides from jujube (Ziziphus jujuba Mill.) fruit

The aim of this paper was to prepare purified fractions of polysaccharides from jujube (Ziziphus jujuba Mill.) fruit and further compare their structural characteristics and antioxidant activities. Firstly, three purified jujube polysaccharides, named PZMP1, PZMP2 and PZMP3, were successfully prepared by DEAE-Sepharose Fast Flow and Sephacryl S-300 columns. Then, their characteristics were studied and then compared by using chemical testing, high-performance gel permeation chromatography (HPGPC), gas chromatography (GC), Fourier transform infrared spectroscopy (FT-IR), methylation analysis, NMR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Thereafter, their antioxidant activities were also contrasted. The data achieved demonstrated that the three jujube polysaccharides derived from different adsorption capacity of DEAE-Sepharose Fast Flow and Sephacryl S-300 columns possessed different structural characteristics and antioxidant activity, and with higher galacturonic acid content could exhibit better antioxidant bioactivities, which could provide certain directions for the functional and medicinal purposes development of jujube polysaccharides.

Physicochemical properties of pectin from Malus domestica ‘Fălticeni’ apple pomace as affected by non-conventional extraction techniques

Six non-conventional techniques (microwave-assisted extraction, ultrasound-assisted extraction, enzyme-assisted extraction – with cellulase and Celluclast 1.5L, ultrasound-assisted extraction – heating treatment, and enzyme-assisted extraction – ultrasound treatment) and conventional citric acid extraction were applied to extract pectin from Malus domestica ‘Fălticeni’ apple pomace, and were compared in terms of extraction yields and physicochemical properties of the pectins. Microwave extraction led to the highest extraction yield and the lowest pectin recovery was found for the extraction with Celluclast 1.5L. Pectin samples obtained by microwave extraction showed color parameters comparable to commercial apple and citrus pectin, and had high galacturonic acid content, increased equivalent weight and high degree of esterification and molecular weight. High galacturonic acid content, molecular weight and degree of esterification were also found for pectin extracted by ultrasonication. On the opposite side, enzymatically extracted pectins had high equivalent weight, but lower degree of esterification that classified pectin extracted with cellulase as low-methoxylated pectin. Pectins obtained by ultrasound-assisted extraction – heating treatment and microwave extraction showed thermal properties that were similar to that of commercial pectins. The rheological characterization of pectin samples highlighted the high viscosities of solutions prepared with pectin from the ultrasound- and microwave-assisted extractions, which were correlated with their molecular weight and galacturonic acid content.