Galacturonic Acid Content Research Articles

Physico-chemical and viscoelastic properties of high pressure homogenized lemon peel fiber fraction suspensions obtained after sequential pectin extraction

The viscoelastic properties of high pressure homogenized lemon peel cell wall fiber suspensions, obtained after sequential selective pectin extraction, were investigated in the current study. For comparison, a general pectin extraction was additionally performed on lemon peel under acid thermal conditions. The obtained insoluble residues and solubilized pectin fractions were characterized based on their neutral sugar and galacturonic acid content, degree of methoxylation and molar mass distribution. Subsequently, microstructure and viscoelastic characteristics of the diverse insoluble residue suspensions were investigated by means of microscopic visualization, determination of the particle size distribution and rheological properties after high pressure homogenization.Due to the use of different extraction conditions, the insoluble cell wall residues were found to have diverse pectin characteristics and contents. While homogenization of non- or moderate-depleted cell wall suspensions resulted in small viscoelastic moduli due to the disruption of the stiff microfibrillar cell wall network, extensive pectin removal was found to correlate to large viscoelastic moduli of the cell wall suspension upon high pressure homogenization. It is suggested that an extensive pectin extraction resulted in the creation of interfibrillar voids within the cellulose-hemicellulose network, increasing the cell wall flexibility and hydration of the fibers upon suspension. Due to the increased flexibility of this fiber network, the interfibrillar voids in the pectin depleted cell wall material were proposed to expand with increasing pressure level during high pressure homogenization of the generated cell wall suspensions, thereby increasing its viscoelastic properties.

Pectin isolation and characterization from six okra genotypes

Pectin was isolated by aqueous extraction at pH 6.0 from the pods of six different okra genotypes (Abelmoschus esculentus L.). Genetic diversity was determined using fragment length analysis (FLA) of ten simple sequence repeat (SSR) markers. Physical and chemical evaluation of pectin was performed by means of FT-IR and NMR spectroscopy, sugar composition analysis (GC-MS), size exclusion chromatography coupled to multi-angle laser light scattering (SEC-MALLS), dilute solution viscometry and steady shear rheology assisted by principal component analysis (PCA). Each of the SSR markers detected on average 4.1 alleles and revealed unique genotypes for each sample. Extraction yield was between 11 and 14% resulting in pectin with galacturonic acid content between 43 and 63%, low degree of methyl-esterification (17–25%) and high degree of acetylation (20–40%). All samples were of high weight-average molar mass (Mw) (700–1700 × 103 g mol−1) and sugar composition analysis revealed the structural diversity of samples with HG/RG-I ratios ranging between 1.3 and 3.1. The present work shows that individual okra genotypes provide pectin with different structural properties that could potentially provide a new source of functional pectin for the food or pharmaceutical industries.

Optimization of pectin extraction from pistachio green hull as a new source

In this paper, the influence of pH (0.5–2.5), temperature (50–90°C), extraction time (30–150min) and liquid/solid ratio (10–50v/w) on the acidic extraction yield and degree of esterification (DE) of pistachio green hull pectin were studied by using central composite design. The results indicated that the yield and DE of pectin ranged from 7.31 to 19.02% and 26.00 to 53.01%, respectively. The optimization of pectin extraction condition showed that the optimal condition was pH of 0.5, temperature of 90°C, time of 30min and liquid/solid ratio of 50 v/w. In this condition, the experimental yield (22.1±0.5%) was fine accord among predicted yield (23.42%). Also, under the optimal extraction condition, the galacturonic acid content of pectin was about 65%. The FTIR spectrum showed that the pectin extracted under optimal condition is rich from polygalacturonic acid.

Structural and functional properties of pectin extracted from jackfruit (Artocarpus heterophyllus) waste: Effects of drying

ABSTRACTPectin extracted from jackfruit waste was dried using different drying techniques, and the chemical composition and structure, flowability, appearance, solubility, and flow behaviour of the dried materials were determined. Yield, galacturonic acid content, and the degree of esterification were found within the ranges of 7–11, 62–68, and 59–66%, respectively, for freeze-dried, spray-dried, vacuum oven-dried, and oven-dried pectin samples from jackfruit waste. Fourier transform infrared spectral analysis showed no major structural differences in the pectin samples produced by the various drying techniques, and their surface structures were comparable to those of analytical and food pectin. The drying methods did not significantly affect the chemical composition (p > 0.05) but did significantly affect the physical appearance, viscosity, and solubility of jackfruit waste pectin (p < 0.05).

The Best Solvent And Extraction Time In Pectin Production made From Waste Of Jackfruit (Bark and Straw)

Jackfruit barks are known to have fairly high pectin content, by 4.7% on wet and 22.5% on dry barks. The content is sufficiently highboy make it worthy of being raw material for producing pectin. Pectin is a polygalacturonic acid containing methyl ester. Pectin is a high- value functional food that is widely used as gelling agent and stabilizer. Approximately 65 until 80% jackfruit barks were wasted from the industry and it were only useful for animal feed . To increase the added value of it, so that jackfruit barks were extracted to get the pectin. This research used randomized block design (RBD) with 2 factors:(i)the type of solvents(hydrochloric and citric acids, with pH = 1.5) and (ii) extraction times (30, 90 and 150 minutes). Each factor is conducted in triplicate in order to get 18 units of experiment. Before analyzed, the jackfruit waste (bark and straw) was powdered during sample preparation. Later on, the yield, equivalent weight, methoxyl, galacturonic acid, and ash contents of the powdered, then were analyzed and used as pectin’s parameters. Multiple attribute method (Zeleny method) was used to determine which combination of treatments that produced pectin with the best pectin’s parameter. The best pectin made from jackfruit waste is derived from the combination of citric acid solvent and the extraction time of 150 minutes, resulting in yield of 10.21%, methoxyl content of 9.25%, equivalent weight of 1088.43 g/mol, ash content of 2.79%, and galacturonic acid content of 47.40%.

Optimization of pectin extraction from orange juice waste assisted by ohmic heating

Ohmic heating is an alternative fast and uniform heating which can extract biomaterials more efficiently than the conventional heating from plant cell walls. Central Composite Designwas employed to study the effect of voltage gradient, temperature and time on the yield, galacturonic acid content and degree of esterification of the pectin. Resultsshowed that the highest yield of pectin (14.32g/100g d. m.) was obtained at the optimum conditions including voltage gradient of 15V/cm, temperature of 90°C during 30min and was significantly (p <0.05) higher than the pectin yield obtained by conventional method (13.53g/100g d. m.). The emulsifying activity of the pectin extracted under the optimal conditions was 67.18 ± 3.77% which was similar to those obtained from the pectin extracted by conventional heating. In addition, the emulsions were maintained 91.88 to 94.87% stable after 30days of storage. The flow behavior of the optimal pectin solutions at concentration of 0.5% w/v was the Newtonian, while at higher concentration (2% w/v), pseudoplastic flow was observed

Enzymatic extraction of pectin from passion fruit peel (Passiflora edulis f. flavicarpa) at laboratory and bench scale

Passion fruit peel, a waste product from the fruit processing industry, was used as feedstock for pectin extraction. For this purpose, a novel process was developed at flask scale using a crude extract of the fungal enzyme protopectinase-SE. The enzymatic pectin extraction was compared with the classic chemical extraction and scaled-up to 7 L stirred tank bioreactor. Pectin yields (measured as galacturonic acid) of 17–26 g/100 g of dry peel were achieved with the enzymatic extraction, which were 6–40% higher than that obtained with the traditional chemical extraction method. Effect of agitation speed, enzyme loading, pH, and temperature were evaluated, and all factors but agitation speed had a significant effect on the pectin yield. Best yields were obtained using 30 U/mL of protopectinase-SE loading at pH 3.0 and 37 °C. Scale-up to bench scale (7 L bioreactor) was successful using Reynolds or Froude number as scale-up criteria, achieving similar yields to those obtained in flasks, but with a slightly lower extraction rate. Enzymatic extracted passion fruit pectin had a galacturonic acid content of 85 g/100 g and a degree of esterification of 68%, similar to commercial citrus pectin.

Extraction optimization and physicochemical properties of pectin from melon peel

In this study, acidic extraction (citric acid) was used for the extraction of pectin from melon peel. A central composite design (CCD) was applied to study the effect of temperature (35–95°C), time (40–200min), pH (1–3) and solvent to sample ratio (10–50v/w) on the yield and degree of esterification (DE). The results showed that the yield and DE ranged from 2.87 to 28.98% and 1.33–29.33%, respectively. Also, the highest extraction yield (29.48±1.7%) was obtained under optimal conditions (pH of 1, temperature of 95°C and ratio of 10v/w after 200min). The protein, ash, carbohydrate and galacturonic acid content of pectin obtained under optimal conditions were about 1.5, 3.5, 10 and 48%, respectively. Rheological experiments determined that melon peel pectin dispersions behaved as a weak gel at concentrations of 1%w/v. The emulsifying activity was 35% and also, the emulsion stability was higher at 4°C than at 23°C.

Effect of extraction condition on properties of pectin from banana peels and its function as fat replacer in salad cream.

Banana peels are wasted from banana processing industry. Pectin is a soluble dietary fibre usually prepared from fruit and vegetable processing wastes. Pectin extraction from banana peels thus should be an effective way of waste utilization. This study aimed to determine the effect of extraction condition on the properties of pectin from peels of Nam Wa banana (Musa (ABB group) 'Kluai Nam Wa') and its role as fat replacer in salad cream. Banana peel pectin (BPP) was extracted with HCl (pH 1.5) and water (pH 6.0) for 30-120min at 90±5°C. Acid extraction yielded 7-11% pectin on a dry basis with galacturonic acid content (GalA), degree of methylation (DM), and viscosity-average molecular weight (Mv) of 42-47, 57-61%, and 17-40kDa, respectively; while water-extracted BPP contained lower DM but higher GalA and Mv. Prolonged extraction raised the pectin yield but lowered the Mv of BPP and the viscosity of their solutions. Incorporation of BPP obtained from 60min acid- and water-extraction into salad cream at 30% oil substitution level resulted in the decreases in viscosity and lightness. All reduced-fat samples were stable to cream separation during 3-weeks storage although the formula containing water-extracted BPP had larger oil droplet size and greater extent of droplet flocculation. There was no difference in sensory scores rated by 50 panelists on thickness, smoothness, and overall acceptability of the full- and reduced-fat salad creams. Therefore, Nam Wa banana peels can be an alternative source of pectin with potential application as fat replacer in food products.

Changes of pectin nanostructure and cell wall stiffness induced in vitro by pectinase

Structural modifications of fruit cell-wall pectins are controlled by various enzymes. In this in vitro study, the cell wall material (CWM) from pear fruit (Pyrus communis L.) was treated using pectinases in two concentrations. Water soluble (WSP), chelator soluble (CSP) and sodium carbonate soluble (DASP) pectin fractions were extracted from CWM. By visualization of enzymatic-induced changes of structure and CWM stiffness using an atomic force microscopy (AFM), the role of pectins in the mechanical properties of cell walls was shown. Galacturonic acid (GalA) content in pectin fractions was assayed as well. This experiment unveiled evidence of the structural degradation of molecules in pectin fractions extracted from CWM caused by in vitro pectinase action and softening of CWM due to pectin removal that might be related to the creation of empty spaces in the cellulose-hemicellulose network.

Pectin from carrot pomace: Optimization of extraction and physicochemical properties

In this study, the central composite design for four variables in five levels was applied to determine the effects of pH (0.5–2.5), temperature (50–90°C), heating time (30–150min) and liquid/solid ratio (10–50v/w) on the yield and degree of esterification (DE) of carrot pomace pectin. The results showed that the pectin yield ranged from 5.0 to 15.2% and also, this pectin is classified as low methoxyl pectin (DE of 22.1–51.8%). The pH of 1.3, temperature of 90°C, time of 79.8min and liquid/solid ratio of 23.3v/w were determined as optimal conditions with a maximum yield of 15.6±0.5%, which was close to the predicted values (16.0%). Under the optimal extraction conditions, the galacturonic acid content and emulsifying activity were 75.5 and 60.3% respectively; moreover, the emulsions had a high stability at two different storage temperatures (4 and 23°C). Furthermore, carrot pectin solutions exhibited viscous and pseudoplastic behavior at 1% w/v.

Physicochemical and rheological properties of gelling pectin from Sosnowskyi's hogweed (Heracleum sosnowskyi) obtained using different pretreatment conditions

Using extraction with 0.7% aqueous ammonium oxalate, Sosnowskyi's hogweed pectins (yield 5–10%) with high molecular weight (200–700 kDa) and galacturonic acid content (70–85%), low degree of methylation (17–28%) and neutral sugar content (7–15%) were isolated from fresh, previously air-dried and frozen plant materials. All plant raw materials were pretreated with aqueous formaldehyde at 25 °C and dilute hydrochloric acid (pH 1.0 or 4.0, 50 °C). The different pretreatments of plant raw material slightly affected yield, chemical composition and molecular weight (average value and distribution) of hogweed pectin. The 13C-NMR spectroscopy indicated the similar structure of the pectins isolated from fresh and air-dried hogweed raw materials. The pectins were differed slightly in thermal degradation depending on the type of hogweed raw material. The aqueous solutions of hogweed pectins had a pseudoplastic flow behavior. Dynamic oscillatory shear tests showed that the pectin hydrogels in the presence Ca2+ (R∼0.6) represent true gels. The pectins from fresh plant material (pH 4.0) formed stronger gel networks (G' ∼2400 Pa) then compared to pectins from air-dried (G' ∼1400 Pa) and frozen (G' ∼900 Pa) plant raw materials. The pectin gelispheres of different size, particle shape, density and textural parameters were prepared by ionotropic gelation. The gelispheres derived from hogweed pectins (fresh and air-dried raw materials) were more stiffness compared to the gelispheres from the commercial low methoxyl apple pectin.

Pectins from food waste: Extraction, characterization and properties of watermelon rind pectin

Fresh and lyophilized watermelon rinds were treated with boiling ethanol for pigment removal and then used to extract pectins giving rise to fractions FW and LW, respectively. The pectins were characterized by chromatographic and spectroscopic methods. Both pectins had a galacturonic acid content higher than 65%, meeting the commercial requirement. However, FW had a higher yield (19.3%) than LW (14.2%). The protein contents were 3.9 and 3.6% for FW and LW, respectively. FW and LW had a high degree of methyl-esterification (∼60%) and low molar mass, 34,510 g/mol for FW and 40,390 g/mol for LW. The viscosity of 5% (w/w) aqueous solutions of watermelon rind pectins at 25 °C showed shear thinning behavior with a low shear Newtonian plateau of ∼30 Pa s for FW and ∼10 Pa s for LW. Mechanical spectra of FW and LW at 5% (w/w) at 25 °C showed a weak gel like behavior for both pectins. The dynamic surface tension, foaming ability and emulsifying properties of FW and LW were evaluated and compared with gum Arabic. FW and LW showed lower dynamic surface tension and higher foaming ability than gum Arabic at the same concentration. Emulsions were prepared with polysaccharides at concentrations ranging from 0.5% to 4% (w/w). The droplet size decreased for both pectins as the concentration increased. Values of surface weighted mean diameter D[3,2] and volume weighted mean diameter D[4,3] obtained for emulsions prepared with FW and LW were found to be similar to gum Arabic, which is well known for its emulsifying properties.

Pectin from Opuntia ficus indica: Optimization of microwave-assisted extraction and preliminary characterization.

Optimization of microwave-assisted extraction (MAE) of water-soluble pectin (WSP) from Opuntia ficus indica cladodes was performed using Response Surface Methodology. The effect of extraction time (X1), microwave power (X2), pH (X3) and solid-to-liquid ratio (X4) on the extraction yield was examined. The optimum conditions of MAE were as follows: X1=2.15min; X2=517W; X3=2.26 and X4=2g/30.6mL. The maximum obtained yield of pectin extraction was 12.57%. Total carbohydrate content of WSP is about 95.5% including 34.4% of Galacturonic acid. Pectin-related proteins represent only the 0.66% of WSP mass. HPSEC and light scattering analyses reveal that WSP is mostly constituted of high molecular pectin and FTIR measurements show that the microwave treatment does not alter the chemical structure of WSP, in which Galacturonic acid content and yield are 34.4% and 4.33%, respectively. Overall, application of MAE can give rise to high quality pectin.

Brönsted acidic ionic liquid based ultrasound-microwave synergistic extraction of pectin from pomelo peels

3-Methyl-1-(4-sulfonylbutyl) imidazolium hydrogensulfate, [HO3S(CH2)4mim]HSO4, was applied as an extractant in an ultrasound-microwave synergistic extraction approach to substitute conventional solvent for the extraction of pectin from the albedo part of pomelo peels. The analysis of variance (ANOVA) test and response surface method were employed for the optimization of the extraction conditions. A pectin yield of 328.64±4.19mg/g was achieved using the obtained optimal conditions, which was significantly higher than yields of conventional methods with reference solvents. Pectin samples extracted with [HO3S(CH2)4mim]HSO4 and hydrochloric acid solutions were tested by ANOVA and showed no significant differences in total carbohydrate content and degree of esterification; while galacturonic acid content was significantly different for the pectin from each extraction solvents. The differences revealed from images of atomic force microscopy and scanning electron microscope, Fourier transform infrared spectroscopy, and thermogravimetric analysis suggested the physiochemical properties of pectin could be affected by the extraction solvent. The [HO3S(CH2)4mim]HSO4 proved to be a promising alternative to conventional solvents and the proposed method is efficient for the extraction of pectin from the albedo of pomelo peels.

Investigation on the influence of pectin structures on the pasting properties of rice starch by multiple regression

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 < 0.05) influences on pasting properties of RS. Multiple regression analysis was adopted to establish equations between structural characteristics of pectin and pasting properties of RS. The obtained equations had a good fit (all R2 ≥ 0.936), and relative errors of pasting properties for prediction group were very close to the coefficient of variation (except breakdown). The contribution of the specific pectin structural characteristic on the change of the pasting properties of RS was also evaluated. DM was greatly correlated with peak and trough viscosity. Breakdown was strongly affected by DA and GA. Two primary factors that affected setback were the MW and GA. Furthermore, peak time was mainly influenced by DA.

Ultrasonic degradation of sweet potato pectin and its antioxidant activity

The effect of ultrasound factors (time, power, and duty cycle) on sweet potato pectin molecular weight, neutral sugar composition, pectin structure, and antioxidant activity was investigated. Sweet potato pectin dispersions (0.0025, 0.005 and 0.01g/mL) in deionized water were sonolyzed for 5, 10 and 20min to assess effect of sonication time and pectin concentration on sonolysis. For further experiments 0.0025g/mL was sonicated under varying ultrasonic power and duty cycle levels, subsequently the molecular weight, galacturonic acid content, degree of methoxylation and antioxidant activity of sonicated pectin products were investigated. Results showed that ultrasound treatment reduced pectin molecular weight, while polydispersity did not show clear trend which characterized random pectin scission, increasing duty cycle from 20% to 80% resulted in approximately threefold reduction in pectin molecular weight, increased sonication power from 100W to 400W led to significant increase in galacturonic acid content from 72.0±1.2% in native pectin to between 85.0±3.2% and 92.0±2.7%, the degree of methoxylation significantly reduced from 12.0±3.0% to between 5.25% and 6.28%, sonication led to increase in galactose and decrease in rhamnose consistent with debranching of pectin. Moreover, sonication lead to increased antioxidant capacity, both 200W and 400W sonicated pectin having higher ORAC and FRAP values, with highest pectin concentration 4mg/mL in ORAC and 0.8mg/ml in FRAP giving substantially high antioxidant activity than native and 100W treated pectin. The ORAC value of 400W sonicated pectin increased five hold above the native pectin, while it’s FRAP value was almost three fold higher than native pectin. However, ultrasound did not alter pectin primary structure as showed by FTIR and HPAEC results. The results indicated that ultrasound offers effective and green process for pectin transformation and creation of antioxidant potent pectin products.

Sequential ultrasound-microwave assisted acid extraction (UMAE) of pectin from pomelo peels

This study aims to optimize sequential ultrasound-microwave assisted extraction (UMAE) on pomelo peel using citric acid. The effects of pH, sonication time, microwave power and irradiation time on the yield and the degree of esterification (DE) of pectin were investigated. Under optimized conditions of pH 1.80, 27.52min sonication followed by 6.40min microwave irradiation at 643.44W, the yield and the DE value of pectin obtained was respectively at 38.00% and 56.88%. Based upon optimized UMAE condition, the pectin from microwave-ultrasound assisted extraction (MUAE), ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE) were studied. The yield of pectin adopting the UMAE was higher than all other techniques in the order of UMAE>MUAE>MAE>UAE. The pectin’s galacturonic acid content obtained from combined extraction technique is higher than that obtained from sole extraction technique and the pectin gel produced from various techniques exhibited a pseudoplastic behaviour. The morphological structures of pectin extracted from MUAE and MAE closely resemble each other. The extracted pectin from UMAE with smaller and more regular surface differs greatly from that of UAE. This has substantiated the highest pectin yield of 36.33% from UMAE and further signified their compatibility and potentiality in pectin extraction.

Compositional evaluation of selected agro-industrial wastes as valuable sources for the recovery of complex carbohydrates

Re-utilization of various agro-industrial wastes is of growing importance from many aspects. Considering the variety and complexity of such materials, compositional data and compliant methodology is still undergoing many updates and improvements.Present study evaluated sugar beet pulp (SBP), walnut shell (WS), cocoa bean husk (CBH), onion peel (OP) and pea pods (PP) as potentially valuable materials for carbohydrate recovery. Macrocomponent analyses revealed carbohydrate fraction as the most abundant, dominating in dietary fibres. Upon complete acid hydrolysis of sample alcohol insoluble residues, developed procedures of high performance thin-layer chromatography (HPTLC) and high performance liquid chromatography (HPLC) coupled with 3-methyl-1-phenyl-2-pyrazolin-5-one pre-column derivatization (PMP-derivatization) were used for carbohydrate monomeric composition determination. HPTLC exhibited good qualitative features useful for multi-sample rapid analysis, while HPLC superior separation and quantification characteristics. Distinctive monomeric patterns were obtained among samples. OP, SBP and CBH, due to the high galacturonic acid content (20.81%, 13.96% and 6.90% dry matter basis, respectively), may be regarded as pectin sources, while WS and PP as materials abundant in xylan-rich hemicellulose (total xylan content 15.53%, 9.63% dry matter basis, respectively). Present study provides new and valuable compositional data for different plant residual materials and a reference for the application of established methodology.

Physico-chemical characterization of water-soluble pectic extracts from Rosa damascena, Calendula officinalis and Matricaria chamomilla wastes

Water soluble pectic extracts were obtained from industrial wastes of three essential oil plants–Rosa damascena (rose), Calendula officinalis (marigold) and Matricaria chamomilla (camomile) as novel approach for valorization of these residues. The higher yield was observed for pectic extract isolated from waste rose petals–11%. Their chemical composition was investigated and was found that rose and marigold polysaccharides were medium methoxylated (DM around 50%) and camomile was low-methoxyl pectic extracts. The three pectic extracts had galacturonic acid content more than 50%. The lowest surface tension value showed pectic extract isolated from camomile wastes and it was comparable with beet and butternut pectins, guar and locust bean gums. The emulsifying properties (50% oil in water emulsions) of the isolated extracts were investigated. It was found that camomile pectic extract emulsions had the highest mechanical stability and marigold pectic extract derived emulsions were the least influenced by the storage temperatures. The data from differential thermal analysis (DTA) showed that the polysaccharide extracts were thermally stable until 220 °C. To our knowledge this is the first attempt for utilization of camomile and marigold wastes as source of pectic extracts and characterization of physico-chemical properties of water-soluble pectic extracts obtained from Rosa damascena, Calendula officinalis and Matricaria chamomilla residues.