High Degree Of Esterification Research Articles

Antioxidant Active Polysaccharides Extracted with Oxalate from Wild Blackthorn Fruits (Prunus spinosa L.).

Although several therapeutic effects have been attributed to wild blackthorn fruits, their use is still negligible. Purification of the antioxidant-active fraction, obtained from wild blackthorn fruits by hot ammonium oxalate extraction (Ao), yielded seven fractions after successive elution with water, sodium chloride and sodium hydroxide solutions. The purified fractions differ in carbohydrates, proteins, and phenolics. About 60% of the applied Ao material was recovered from the column, with the highest yields eluted with 0.25 M NaCl solution, accounting for up to 70 wt% of all eluted material. Analyses have shown that two dominant fractions (3Fa and 3Fb) contain 72.8-81.1 wt% of galacturonic acids, indicating the prevalence of homogalacturonans (HG) with a low acetyl content and a high degree of esterification. The low content of rhamnose, arabinose and galactose residues in both fractions indicates the presence of RG-I associated with arabinogalactan. In terms of yield, the alkali-eluted fraction was also significant, as a dark brown-coloured material with a yield of ~15 wt% with the highest content of phenolic compounds of all fractions. However, it differs from other fractions in its powdery nature, which indicates a high content of salts that could not be removed by dialysis.

Physicochemical and antioxidant properties of pectin from Actinidia arguta Sieb.et Zucc (A. arguta) extracted by ultrasonic.

Pectin was extracted from Actinidia arguta Sieb. et Zucc (A.arguta) using the ultrasound-assisted acid method and the single acid method. The physicochemical properties, structure, and antioxidant properties of two different pectins were investigated. The results showed that the extraction yield of the ultrasound-assisted acid method is higher than that of the single acid method. The molecular structure of A. arguta pectin extracted by the ultrasound-assisted acid method belongs to a mixed structure of RG-I and HG-type domains. Through structural feature analysis, the ultrasound-assisted extraction pectin (UAP) has a more branched structure than the single acid-extracted pectin (SAP). The SAP has a higher degree of esterification than the UAP. The physical property results show that the viscosity, solubility, and water-holding capacity of the UAP are better than those of the SAP. The antioxidant test results show that the hydroxyl radical scavenging and reducing powers of the UAP are superior to those of the SAP. This study shows the composition, physicochemical properties, and antioxidant activity of A. arguta pectin extracted by the ultrasonic-assisted extraction method to provide a theoretical basis for its application as an antioxidant and other food additives in the food industry.

General characteristics of lavender biomass (Lavandula angustifolia Mill.) before and after industrial distillation

The aim of the present study was to evaluate and compare three types of lavender (Lavandula angustifolia Mill.) biomasses for their content of biologically active substances and potential application. The first one was from unprocessed lavender (L-UNTR22_Z) and the other two were industrial steam-distilled lavender solid residues (L-SD22_Z and L-SD22_M). Ash, protein, polyuronide content and the degree of esterification of the pectic substances in the biomass were investigated. 70% ethanolic extracts of the residues were prepared and their total polyphenol content and antioxidant activity were evaluated by four methods. Individual phenolic acids, flavonoids, polar non-volatile compounds and polar volatile compounds were also determined by chromatographic analyses. The highest degree of esterification (83.9±0.5%) and protein content (8.15±1.6%) were found in L-SD22_Z extract. L-SD22_M extract demonstrated the highest polyphenolic content and antioxidant activity. Six phenolic acids (protocatehuic, syringic, p-coumaric, ferulic, salicylic, and gallic acid) and five flavonoids ((+)-catechin, (-)-epicatechin, rutin, hesperidin, and quercetin) were detected by HPLC analyses. The detail information about amino acids, sugars, organic and phenolic acids, as well as polar volatile compounds was obtained by GC-MS. The results suggested that the lavender (untreated and residual biomass) are a good source of dietary antioxidants and compounds with potent biological activity.

Microwave and ultrasound-assisted natural deep eutectic solvents-based extraction of pectin from onion peel wastes

ABSTRACT Pectin was extracted from onion peels using microwave and ultrasound-assisted natural deep eutectic solvents (NADES) and compared with conventional acid-extracted pectin. The primary screening trials indicated that the suitable combination of hydrogen bond acceptor and donor was choline chloride and tartaric acid, respectively. The Box-Behnken design was further used to optimize processing conditions like microwave intensity (26.903 W/g), microwave processing duration (2.99 min), and sonication duration (10.18 min) for maximizing the pectin yield from onion peel powder. The moisture, ash, and equivalent weight of extracted pectin were in the range specified by the International Pectin Producers Association. The higher anhydrouronic acid content of the NADES-extracted pectin indicated the higher purity of pectin compared to the conventional acid-extracted pectin. The NADES-based extraction was found to be a promising system for extracting pectin with a higher degree of esterification from onion peels.

Effect of hornification on the isolation of anionic cellulose nanofibrils from Kraft pulp via maleic anhydride esterification

Cellulose nanofibrils (CNF) isolation based on a catalyst-free maleic anhydride esterification has proven to be effective, however, the effects of pulp hornification on CNF isolation by this strategy have yet to be explored, which could present significant impacts for CNF isolation. Herein, dried northern bleached softwood Kraft pulp (D-NBSK) and never-dried northern bleached softwood Kraft pulp (ND-NBSK) were selected as the substrates. After esterification with maleic anhydride (MA), the esterified ND-NBSK pulp (E-ND) shows a significantly smaller size and more fragmented structure than the esterified D-NBSK pulp (E-D). Meanwhile, higher degree of esterification can be realized for the never dried pulp as compared to the dried pulp, which is corroborated by the significantly stronger characteristic peaks of CO (1720 cm−1) and -COO− (1575 cm−1) from the FTIR spectra and the higher surface charge content (0.86 ± 0.04 mmol/g vs. 0.55 ± 0.05 mmol/g). A comparison of the characteristics of the resulting CNF similarly demonstrated the negative impact of hornification. Overall, this work indicates that hornification tends to reduce the accessibility of chemical reagents to the pulp, leading to insufficient deconstruction. Such negative impact of hornification should be considered when performing nanocellulose isolation, especially when using pulp as feedstock.

Structural characterization, antioxidant and antibacterial activity of three pectin polysaccharides from blueberry

In this study, three pectin polysaccharides BP1, BP2 and BP3, were purified from blueberries. The weight-average molecular weight (Mw) of BP1, BP2, and BP3 were detected to be 9.027 × 104, 9.313 × 104, and 1.223 × 106 Da, respectively. The structures of the three pectin polysaccharides were characterized and compared based on the results of molecular weight, monosaccharide composition, GC–MS and NMR analysis. Structural characterization revealed that BP1, BP2, and BP3 all contain homogalacturonan (HG) and rhamnogalacturonan I (RG-I) domains, and the rhamnose residues in RG-I domains are substituted at C-4 with side chains such as araban and galactosan. BP2 had the highest degree of esterification and HG domain ratio, followed by BP3 and BP1. In addition, BP1, BP2 and BP3 showed great antioxidant and antibacterial activities, and could destroy the cell membrane of Staphylococcus aureus and Escherichia coli. Moreover, the better DPPH and ABTS free radical scavenging and antibacterial activities of BP1 and BP2 than BP3 might be related to their lower molecular weight. The results of this study will provide essential information for the structure-activity relationship of pectin polysaccharides and research basis for development and application of blueberry pectin polysaccharides.

The effect of citric acid concentrations on the mechanical, thermal, and structural properties of starch edible films

SummaryThis study investigated the effects of citric acid on the properties of edible tapioca starch films plasticised with glycerol. These films were formed using 5% tapioca (w/w of water); 1%, 3%, 5%, 7% and 9% citric acid (w/w of starch); and 2.2% glycerol (w/w of water). Native starch films formed using 5% tapioca and 2.2% glycerol were used as the control. The properties tested included the degree of crosslinking, thermal stability, crystallinity and mechanical properties. These were evaluated using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR‐FTIR), X‐Ray diffraction (XRD), thermal gravimetric analysis (TGA) and tensile profile analysis (TPA). The FTIR results provided information about the nature of the crosslinking in the films, while TGA showed that increasing the citric acid concentration reduced the physical decomposition temperature of the materials. Films containing 9% citric acid had the highest degree of esterification and crosslinking, while those containing 7% citric acid had the lowest heat‐related weight loss that correlated with the degree of crosslinking. The weight loss among all six samples was the greatest in the temperature range 260 °C–350 °C where a total of 60% weight loss occurred. The XRD results showed that films containing 3% citric acid had the lowest crystallinity while the native starch films had the highest crystallinity. The TPA analyses showed that films containing 5% citric acid had the greatest influence on improving the tensile strength and elastic modulus, while also having the best impact on lowering the elongation. Tensile strength values recorded for films containing 0%, 1%, 3%, 5%, 7% and 9% citric acid were 5.327, 7.813, 8.688, 12.855, 14.549 and 11.614 MPa. Similarly, when citric acid concentration increased from 3% to 5%, the elastic modulus significantly increased from 831.058 to 2255.691 MPa. This study demonstrated that the physicochemical properties of tapioca starch‐based films could be modified by the incorporation of citric acid.

Effect of structurally different pectin combined with polyphenol on water distribution, protein oxidation and heterocyclic amines formation in meat-based snacks

This research studied the effect of structurally different pectin combined with polyphenol (PP) on the physicochemical properties, inhibition of protein oxidation and heterocyclic amines (HAs) formation in fish meat snacks. The findings demonstrated that pectin with a high degree of esterification (DE) and average chain length (ACL) significantly reduced cooking loss, improved zeta potential values, and reduced particle size when combined with polyphenols, indicating an inhibition of protein aggregation and crosslinking. The addition of PP decreased the carbonyl formation as compared to individual polyphenol and control. Low Field Nuclear Magnetic Resonance (LF-NMR) analysis publicized that PP combination increased the water binding capacity, which resulted in less free water (T22 and T23) in those samples. Furthermore, LC/MS analysis revealed that PP combination, retained the water inside the macromolecules and prevented the relocation of water to the surface, which resulted in the less HAs formation as compared to control. The scanning electron microscopy (SEM) revealed that combination of PP samples formed a compact structure evidenced by less wide holes while control sample revealed loose structure. The findings suggest that 201 and 601 pectin combined with catechin have potential to improve the physicochemical properties and inhibition of hazardous compound formation.

Comparative study on thermo-mechanical, structural and functional properties of pectin extracted from immature wasted apples and commercial pectin

Pectin yield of 22.22 ± 0.98 % (dry basis) was achieved from prematurely dropped Golden Delicious apples, having a light orange hue (hue value: 78.08 ± 0.04) and an overall color difference (ΔE) of 9.92 ± 0.01 compared to commercial pectin (CP). Extracted AP exhibited a lower equivalent weight (725.24 ± 29.73) and higher methoxy content (8.36 ± 0.28 %) in contrast to CP. However, a similar degree of esterification of 71.57 ± 0.79 and 70.55 ± 0.59 %, was observed in AP and CP respectively. Apple pectin demonstrated slight lower galacturonic acid (GalA) content of 68.10 ± 3.94 % in comparison to 72.31 ± 4.62 % of CP, which was further corroborated by reduced intensity in FTIR fingerprint region (912–1025 cm−1). Morphology revealed a sheet-like cloudy appearance indicating a significant presence of associated sugars whereas X-ray diffraction highlighted the highly amorphous nature of AP. AP and CP solutions (3–9 %) displayed a shear-thinning flow and viscoelastic behavior where the loss (G') moduli dominated over the storage moduli (G"). Owing to high degree of esterification, galacturonic acid content (>65 %) that aligns with commercial standards and viscoelastic behavior, the extracted AP holds promise for potential utilization in commercial applications. This study underscores the potential for sustainable utilization of prematurely dropped apples through pectin extraction, contributing to valorization of the wasted bioresource.

Characterization of pectin extracted from pomelo peel using pulsed ultrasound assisted extraction and acidic hot water extraction process

In the present study, the characteristic properties namely XRD, FTIR, DSC, TGA and FESEM analyses of pectin extracted from pomelo fruit peel using pulsed ultrasound assisted extracted (PUUAE) were compared with those of pectin obtained with the conventional acidic hot water extraction (AHWE) process. The pectin extracted from PUUAE process has been analysed to possess better properties in comparison with the pectin obtained from the AHWE process. Pectin obtained from these two methods had been of high methoxyl pectin with almost similar structure. XRD analysis confirmed that AHWE based pectin possessed lower crystallinity than the PUUAE based pectin. The XRD spectra of PUUAE pectin affirmed sharper and stronger peaks than those of the AHWE based pectin and especially at 18.33° and 29.04° Further, the FTIR study revealed stronger absorption areas for PUUAE based pectin than those pertinent in the AHWE based pectin. This inferred that the pectin extracted with PUUAE had higher degree of esterification than that obtained with the AHWE process. Moreover, the DSC and TGA analyses indicated that PUUAE pectin had higher thermal stability in comparison to AHWE based pectin. The exothermic transition for the PUUAE based pectin was found to occur at higher temperature (245.7 °C) in comparison to the AHWE based pectin sample (239 °C). The TGA study conveyed double-stage decomposition for the PUUAE pectin sample (two DTGA peak temperatures (first at 230 °C and the second at 317 °C)) in comparison to the data obtained for the AHWE based pectin sample (a single peak only appears at 182 °C). The FESEM study affirmed a smoother surface with more structural integrity for PUUAE based pectin than that pertinent in the AHWE pectin sample. Therefore, the obtained characteristics can be inferred to the view that the PUUAE process is effective for the production of high quality pectin from pomelo peel (PP) for relevant functional applications.

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.

Synthesis and study of composite materials based on apple pectin and copper cations

The paper presents the results of synthesis the metal-composite materials based on apple pectin and divalent metal cations - Cu2+; determining the degree of esterification and the content of free carboxyl groups of the native pectin by acid-base titration, determining the degree of inclusion of the specified cation in the polysaccharide macromolecule and studying by IR spectroscopy and fungicidal activity of native pectin and copper complexes against Penicillum sp According to the results of titration, it was found that apple pectin has a high degree of esterification (DE = 50.7%) and a low content of carboxyl groups (Kc = 2.79%), which suggests its low gelling activity. It was found that the increase in salt concentration is above 0.005 g-eq/l. leads to a decrease in the proportion of the resulting water-soluble complex. The optimal concentration of CuSO4 5H2O, at which the largest mass of the water-soluble complex is formed, is 0.005 g-eq/l. According to IR spectroscopy, the degree of substitution of sodium cations for copper cations was calculated, which amounted to 18%. It was shown that the native apple pectin does not have fungicidal activity, while the copper complex based on it is able to suppress the growth of the culture already under the action of 10 µl of the substance, and with an increase in volume to 50 µl, an even more active fungicidal activity of the copper complex appears.

Valorization of pistachio industrial waste: Simultaneous recovery of pectin and phenolics, and their application in low-phenylalanine cookies for phenylketonuria

This study introduces a sustainable approach to simultaneously produce pectin and phenolic compounds from pistachio industrial waste and applies them in the formulation of low-phenylalanine cookies. The co-optimization process was performed using the microwave-assisted technique and a Box-Behnken design, considering four variables and two responses: pectin yield and total phenolic content (TPC). The co-optimized condition (microwave power of 700 W, irradiation time of 210 s, pH level of 1.02, and LSR of 20 mL/g) resulted in a pectin yield of 15.85 % and a TPC of 10.12 %. The pectin obtained under co-optimized condition was evaluated for its physicochemical, structural, and thermal properties and the phenolic extract for its antiradical activity. Characterization of the pectin sample revealed a high degree of esterification (44.21 %) and a galacturonic acid-rich composition (69.55 %). The average molecular weight of the pectin was determined to be 640.236 kDa. FTIR and 1H NMR spectroscopies confirmed the structure of pectin, with an amorphous nature and high thermal stability observed through XRD and DSC analysis. Additionally, the extract exhibited significant antiradical activity comparable to butylated hydroxyanisole and ascorbic acid. The isolated ingredients were used to formulate low-protein, low-phenylalanine cookies for phenylketonuria patients. The addition of 0.5 % pectin and 1 mL/g extract led to increased moisture content (from 9.05 to 12.89 %) and specific volume (from 7.28 to 9.90 mL/g), decreased hardness (from 19.44 to 10.39 N × 102), and improved antioxidant properties (from 5.15 % to 44.60 % inhibition) of the cookies. Importantly, there was no significant increase observed in the phenylalanine content of the samples with pectin and extract addition. Furthermore, sensory evaluation scores demonstrated significantly higher scores for taste, odor, texture, and overall acceptability in cookies enriched with 0.5 % pectin and 1 mL/g extract, with scores of 4.53, 3.93, 4.40, and 4.60, respectively.

Study on the structure, antioxidant activity and degradation pattern of polysaccharides isolated from lotus seedpod

The lotus (Nelumbo nucifera Gaertn.) is the largest aquatic vegetable in Asia. The lotus seedpod (LS) is an inedible part of the mature flower receptacle of the lotus plant. However, the polysaccharide isolated from the receptacle has been less studied.The purification of LS resulted in two polysaccharides (LSP-1 and LSP-2). Both polysaccharides were found to be medium-sized HG pectin, with a Mw of 74 kDa. Their structures were elucidated via GC–MS and NMR spectrum and proposed as the repeating sugar units of GalA connected via α-1,4-glycosidic linkage, with LSP-1 having a higher degree of esterification. They have certain content of antioxidant and immunomodulatory activities. The esterification of HG pectin would have an adverse effect on these activities. Furthermore, the degradation pattern and kinetics of LSPs by pectinase conformed to the Michaelis-Menten model.There is a large amount of LS, resulting from the by-product of locus seed production, and thus a promising source for the isolation of the polysaccharide. The findings of the structure, bioactivities, and degradation property provide the chemical basis for their applications in the food and pharmaceutical industries.

Enzymatic synthesis of propionyl-fructooligosaccharides and their evaluation as a gut microbiota modulator

Propionic acid (PA), an end product of bacterial metabolism, has various functions in the colon. The aim of this study was to use ester bonds to link PA and a prebiotic fructooligosaccharides (FOS) to form propionyl-FOS capable of delivering PA to the colon. We used enzyme assistance and acid anhydride method to produce propionyl-FOS, respectively. FT-IR and NMR were used to confirm the formation of ester bonds. MALDI-TOF-MS was used to characterize the ester diversity and to partly monitor the fate of propionyl-FOS. In vitro simulated gut fermentation was used to study the effect of obtained esters on gut microbiota modulation and metabolite production. Our results showed that chemically synthesized propionyl-FOS (AP-FOS) was propionyl-esterified to a higher degree than enzymatically synthesized ones (P-FOS). Propionyl-fructooligosaccharides were more diverse in AP-FOS than in P-FOS. Higher levels of PA and butyric acid were detected in both AP-FOS and P-FOS groups than in FOS group after 24 h in vitro fermentation. The fermentability and prebiotic effects of AP-FOS were lower than those of P-FOS due to the high esterification degree of the former. Compared to FOS, P-FOS could confer better beneficial health effects through gut microbiota modulation. Hence, enzymatically synthesized P-FOS could be a potential prebiotic for health-promoting properties.

Changes in the structure of polysaccharides under different extraction methods

Changes in the structure of polysaccharides under different extraction methods

Pectin with Low Molecular Weight and High Degree of Esterification Increases Absorption of 58Fe in Growing Rats

Effects of pectins with different degrees of esterification (DE) and molecular weights (MW) on iron bioavailability were investigated in healthy growing rats by following erythrocyte incorporation of a dose of 58Fe. Rats were fed a control diet for 8 d and then deprived of food for 16 h. Two hours after the start of feeding iron-deficient diets, with or without pectin (80 g/kg diet), a dose of FeSO4 rich in 58Fe (60.28%) was intubated into the stomach; rats were then allowed to feed for an additional 4 h before withdrawal of food for 10 h. Rats were then fed iron-adequate diets for 9 d. The pectins differed in DE and MW, respectively, as follows: P-A (73%, 860,000), P-B (75%, 89,000), P-C (22%, 1,260,000) and P-D (24%, 114,000). Rats fed pectin-free diet with free access to food or restricted to the same quantity consumed by a respective pectin group served as controls. Iron absorption was 48% in the control group and 57% in rats fed P-B. Rats fed P-B had higher (P ≤ 0.05) serum iron, transferrin saturation, hematocrit and liver and spleen iron than the control group or the group fed P-C. These indices, except for transferrin saturation, were also higher in rats fed P-A and P-D compared with those fed P-C and controls, but to a lesser extent than in rats fed P-B. The data indicate that bioavailability of dietary non-heme iron was enhanced when pectin of low MW and high DE was added to the diet. This improvement was not evident with pectins having high MW and/or low DE.

Enhancement of industrial pectin production from sugar beet pulp by the integration of surfactants in ultrasound-assisted extraction followed by diafiltration/ultrafiltration

To recover industrial pectin from sugar beet pulp (SBP), a combined surfactant and ultrasound-assisted extraction, followed by a concentration with ultrafiltration/diafiltration membranes is proposed. First, the operation conditions of the extraction were optimized for synthetic (Tween80, PEG4000) and natural (Saponin) surfactants. Tween 80 and Saponin provided maximum galacturonic acid (GalA) concentrations (5.5 and 5.8 g/L, respectively) under the best extraction conditions (4 gsurfactant/L, pH = 1, amplitude = 90%, and time = 90 min). The extracted liquid was purified and concentrated through membranes. The final retentate maintained 73% of the initial GalA and eliminated a high percentage of oligosaccharides. Finally, the pectin was precipitated with ethanol, and the precipitate solid contained 57 g GalA/100 g GalA of SBP with a high degree of esterification (DE = 81%) and MW (930 kDa). The pectin yield for the global process was 24.6%. The ultrasound-assisted extraction with surfactants followed by diafiltration/ultrafiltration could become a promising process for the chemical industry, able to provide pectin-enriched products of commercial interest from sugar beet pulp.

Grape-derived pectic polysaccharides alter the tannin and pigment composition of Cabernet Sauvignon red wines

Tannins, anthocyanins, and polymeric pigments are essential phenolic constituents of red wine because they provide color, color stability, and mouthfeel properties like astringency. The behavior of these compounds is significantly affected by pectic polysaccharides, whereby the extent of their influence on red wine quality depends on their structural features and their interactions with the polyphenols. In the present study, the composition of the pectic polysaccharides of commercially available Cabernet Sauvignon wines and their impact on anthocyanin, tannin, and polymeric pigment analyses was characterized. This was accomplished by preparation of polysaccharide deprived wines and comparison of the polyphenolic composition of both, the wines and their corresponding polysaccharide-free counterparts. The results show that the cell wall fragments enhance the spectral absorbance of anthocyanins by facilitating anthocyanin self-association, leading to a co-pigmentation-like effect. Low molecular weight pectins like rhamnogalacturonan II and polygalacturonic acids with a low degree of esterification are assumed to form soluble complexes with anthocyanins and also prevent protein precipitation of tannins, which was reduced by 6–13%. High molecular weight pectins with a high degree of esterification lead to the increased precipitability of pigments and tannins by a factor of 1.3 to 32.4 and 1.1 to 1.9, respectively, seemingly impairing the incorporation of anthocyanins in tannins to form precipitable polymeric pigments that are responsible for the longevity of red wine color. The increased precipitability of the pigments due to the interactions with the polysaccharides may indicate the formation of pigmented yet non-covalent aggregates that show comparable properties to the covalently formed precipitable pigments. The formation of those non-covalent structures may affect red wine color stability and astringency.

Evaluation of sources and methods of pectin extraction from fruit and Vegetable wastes: A Systematic Literature Review (SLR)

The potentially commercial sources of pectin are limited. Researchers have studied different extraction methods using a wide variety of fruits and vegetables to obtain pectins with better characteristics. The objective of this work was to identify the methods used in the extraction of pectin, the most used sources and the operation parameters that enable the achievement of higher yields and the final characteristics of the obtained product. These are based on bibliometric methods for exploring the structure of knowledge in this field for the last twelve years. To this end, a Systematic Literature Review (SLR) using the SCOPUS database was carried out, which allowed identifying keywords and formulating search equations to find scientific articles on the topic in question. After selecting the articles, a detailed reading of these works was carried out, and the used extraction methods and the evaluated variables, yields and characteristics were analyzed. This article compares and discusses the effects of conventional and non-conventional pectin extraction techniques, which may provide valuable information on sources and alternatives for pectin extraction to ease decision-making in future research. The acid hydrolysis method remains the most widely used pectin extraction technique since it provides higher yields. It is followed by microwave-assisted extraction, ultrasonic extraction, and the enzymatic method, which have a greater capacity to deliver pectins with high methoxyl content. Finally, non-conventional methods such as radiofrequency, ohmic heating, and aqueous two-phase extraction are presented as promising techniques that offer pectins with a high degree of esterification in addition to good yields.