Changes In Pectin Research Articles

Physicochemical Properties of Low-Molecular-Weight Homogalacturonan Pectin from Enzyme-Hydrolyzed Red Okra.

In this study, we focused on reducing the molecular weight of purified red okra pectin using various hydrolytic enzymes and evaluating its physicochemical properties or characterization. The enzyme treatments targeted both the main pectin chain and the side-chain sugars, resulting in a reduction in the molecular weight by approximately 10% (from 647 kDa) to 60% (down to 252 kDa). Both the purified red okra pectin and enzyme-treated pectins exhibited a homogalacturonan (HG)-type backbone. Fourier transform infrared (FT-IR) spectroscopy revealed a decrease in the absorbance peak for the pectin backbone (1200-1000 cm-1) in the low-molecular-weight (LMW) pectin. The most significant decrease was observed at 3300 cm-1 in pectin treated with both RGH+RGAE enzymes, indicating reduced sugar bonds. These results demonstrate the physicochemical changes in LMW red okra pectin following enzyme treatment and confirm its potential applications due to its unique characteristics.

Two Half-Size ATP-Binding Cassette Transporters Are Implicated in Aluminum Tolerance in Soybean.

Aluminum (Al) toxicity severely restricts plant production in acidic soils. ATP-binding cassette (ABC) transporters participate in plant tolerance to various environmental stresses. However, ABC transporters implicated in soybean Al tolerance are still rare. Here, we functionally characterized two half-size ABC transporters (GmABCB48 and GmABCB52) in soybean. Expression analysis showed that GmABCB48 and GmABCB52 were induced only in the roots, especially in the root tips. Both GmABCB48 and GmABCB52 were localized at the plasma membrane. Overexpression of GmABCB48 or GmABCB52 in Arabidopsis reduced Al accumulation in roots and enhanced Al tolerance. However, expression of GmABCB48 or GmABCB52 in yeast cells did not affect Al uptake. Furthermore, transgenic lines expressing GmABCB48 or GmABCB52 had lower Al content in root cell walls than wild-type plants under Al stress. Further investigation showed that the Al content in cell wall fractions (pectin and hemicellulose 1) of transgenic lines was significantly lower than that of wild-type plants, which was coincident with the changes of pectin and hemicellulose 1 content under Al exposure. These results indicate that GmABCB48 and GmABCB52 confer Al tolerance by regulating the cell wall polysaccharides metabolism to reduce Al accumulation in roots.

Effect of degree of esterification on the stability of high internal phase Pickering emulsions (HIPPEs) fabricated with pectin‐whey protein isolate complexes

SummaryThis study examined the effects of different degree of esterification (DE) on the stability of high internal phase Pickering emulsions (HIPPEs) fabricated using pectin‐whey protein isolate complexes. The modified pectin with different DE was prepared using the alkali de‐esterification method with high methoxyl pectin (HMP). The impact of DE on the conformational changes of pectin and whey protein isolate (WPI) during the complexes formation was examined using Fourier transform infrared spectroscopy (FTIR) and fluorescence spectroscopy. Citrus pectin (CP)–WPI complexes and camellia oil were used to create an emulsion with a self‐supporting structure of 75% internal phase volume. The thermal, centrifugal, storage and freeze–thaw stabilities of CP–WPI stabilised HIPPEs with different DE were evaluated and the results revealed that the low methoxyl pectin (LMP) produced via alkali de‐esterification altered the charge density of pectin. Compared with the untreated pectin, the electrostatic interaction between CP–WPI complexes was enhanced and the stability of CP–WPI stabilised HIPPEs was improved. The study will help to better understand the interaction between CP and WPI, enhance the efficiency of the pectin–protein delivery system and improve the utilisation rate of citrus pectin, which has important guiding significance.

Ultrasound modification of pectin and the mechanism of its interaction with cyanidin-3-O-glucoside

The present study investigated water-soluble pectin (WSP), chelating pectin (CSP), sodium carbonate-soluble pectin (NSP), and cyanidin-3-O-glucoside (C3G). Various ultrasonic treatments (688, 1376, 2064, 2431, and 3437 W/cm2, 10 min) were used to modify the three types of pectin, and the structural changes in pectin and the interaction mechanisms between pectin and cyanidin were analysed. The experimental results indicated that ultrasonic (US) modification reduced the molecular weight and degree of methylation (DE) of pectin. The DE values of WSP and CSP decreased by 24.51% and 80.12%, respectively. US modification disrupted the branched structure of pectin and reduces the ratio of rhamnose/galacturonic acid, which caused an increase in the linearity of pectin. US modification enhanced the interaction between the three pectins and anthocyanins, and the US condition of 2064 W/cm2 for 10 min increased the binding rate by 15.71%–46.18%. NSP had the largest binding rate, and US modification had the greatest improvement in WSP binding rate. After US modification, the particle size of the pectin-cyanidin complex decreased, and the zeta potential increased. After heat treatment, the residual mass percentage of the pectin-C3G complex increased, which suggested that the encapsulation of C3G in pectin improved thermal stability. Therefore, US treatment is a versatile processing tool that reduces the DE of pectin and enhances its linearity, which offers a promising approach to promoting pectin-C3G complexes.

Effects of high voltage dielectric barrier discharge on the extraction and properties of pectins from watermelon rinds

High-voltage dielectric barrier discharge (DBD) pretreatments of watermelon rinds were conducted at 12, 16, and 20 kV cm-1 to extract pectin. The DBD pretreatment at 20 kV cm−1 had significantly impacted pectin extraction, increasing yield from 17.4% to 18.5%. A kinetic study had shown that pectin extraction can be properly modeled using a pseudo-first-order kinetic model. The pectins obtained from conventional extraction and DBD pretreatment had galacturonic acid contents ranging from 79.02% to 80.25% and average molecular weights between 222 and 402 kDa. The exposure to the DBD pretreatment had increased total monosaccharides, branching index, and the rhamnogalacturonan domain of pectin. Fourier transform infrared spectroscopy analysis had not indicated a formation of new functional groups or significant structural changes but had increased functional group intensity. X-ray diffraction showed no significant changes in pectin's crystalline structure due to DBD pretreatment.

The Resistance of Maize to Ustilago maydis Infection Is Correlated with the Degree of Methyl Esterification of Pectin in the Cell Wall.

Common smut caused by Ustilago maydis is one of the dominant fungal diseases in plants. The resistance mechanism to U. maydis infection involving alterations in the cell wall is poorly studied. In this study, the resistant single segment substitution line (SSSL) R445 and its susceptible recurrent parent line Ye478 of maize were infected with U. maydis, and the changes in cell wall components and structure were studied at 0, 2, 4, 8, and 12 days postinfection. In R445 and Ye478, the contents of cellulose, hemicellulose, pectin, and lignin increased by varying degrees, and pectin methylesterase (PME) activity increased. The changes in hemicellulose and pectin in the cell wall after U. maydis infection were analyzed via immunolabeling using monoclonal antibodies against hemicellulsic xylans and high/low-methylated pectin. U. maydis infection altered methyl esterification of pectin, and the degree of methyl esterification was correlated with the resistance of maize to U. maydis. Furthermore, the relationship between methyl esterification of pectin and host resistance was validated using 15 maize inbred lines with different resistance levels. The results revealed that cell wall components, particularly pectin, were important factors affecting the colonization and propagation of U. maydis in maize, and methyl esterification of pectin played a role in the resistance of maize to U. maydis infection.

Mechanistic understanding of the effect of sodium citrate soaking of red kidney beans on their cooking behaviour

In this study, the role of soaking beans in a sodium citrate solution (a cation chelator) at pH = 4.4 and 41 °C in directing/improving the cooking behaviour of common beans was explored. The cooking behaviour of the pre-soaked red kidney beans was determined and the corresponding changes of phytate, minerals, starch, protein and pectin were quantified. Soaking beans in citrate buffer could accelerate softening of the beans during cooking in deionised water while subsequent cooking of beans in this buffer had a limited additional effect on softening compared to cooking in deionised water. Phytate hydrolysis during soaking in citrate buffer results in a release of Mg2+ and Ca2+. Both cations were leached into the soaking medium, higher amounts being observed for Mg2+ release to the soaking media because of the lower affinity of Mg2+ for pectin. It was observed that the pectin solubilisation rate in beans treated by sodium citrate buffer was positively correlated to bean softening. All of these results point out that soaking in a citrate buffer prohibits pectin Ca2+ cross linking therefore enhancing pectin solubilisation and thus increasing the bean softening rate constants during cooking, while starch and protein were not responsible for texture evolution.

A Pectate Lyase Gene Plays a Critical Role in Xylem Vascular Development in Arabidopsis.

As a major component of the plant primary cell wall, structure changes in pectin may affect the formation of the secondary cell wall and lead to serious consequences on plant growth and development. Pectin-modifying enzymes including pectate lyase-like proteins (PLLs) participate in the remodeling of pectin during organogenesis, especially during fruit ripening. In this study, we used Arabidopsis as a model system to identify critical PLL genes that are of particular importance for vascular development. Four PLL genes, named AtPLL15, AtPLL16, AtPLL19, and AtPLL26, were identified for xylem-specific expression. A knock-out T-DNA mutant of AtPLL16 displayed an increased amount of pectin, soluble sugar, and acid-soluble lignin (ASL). Interestingly, the atpll16 mutant exhibited an irregular xylem phenotype, accompanied by disordered xylem ray cells and an absence of interfascicular phloem fibers. The xylem fiber cell walls in the atpll16 mutant were thicker than those of the wild type. On the contrary, AtPLL16 overexpression resulted in expansion of the phloem and a dramatic change in the xylem-to-phloem ratios. Altogether, our data suggest that AtPLL16 as a pectate lyase plays an important role during vascular development in Arabidopsis.

Targeted multi-platform metabolome analysis and enzyme activity analysis of kiwifruit during postharvest ripening.

Kiwifruit is a climacteric fruit, in which the accumulation of flavor substances mainly occurs at the postharvest ripening stage. However, the dynamic changes in metabolite composition remain poorly understood. Here, targeted multi-platform metabolome analysis based on GC-MS and UPLC-MS/MS and enzyme activity analysis were performed at different postharvest ripening stages of kiwifruit. A total of 12 soluble sugars and 31 organic acids were identified. The main soluble sugars are sucrose, glucose and fructose, which exhibited similar variation tendencies along with the extension of ripening. The main organic acids are citric acid, quinic acid and malic acid, which showed different variation patterns. A total of 48 energy metabolites were identified, which were classified into two groups based on the content variation. The content of substances related to the respiratory metabolic pathway decreased gradually along with postharvest ripening, and there was obvious accumulation of downstream products such as amino acids at the late ripening stage. A total of 35 endogenous hormones were identified, among which seven cytokinins were highly accumulated at the later stage of softening. We further investigated the dynamic changes in the activities of 28 ripening-related enzymes. As a result, the activities of 13 enzymes were highly correlated with changes in starch, total pectin, and soluble sugars, and those of seven enzymes were closely associated with the change in firmness. In conclusion, this study comprehensively describes the dynamic changes in soluble sugars, organic acids, hormones, energy substances, and ripening-related enzyme activities during kiwifruit postharvest ripening, and provides a theoretical basis for the postharvest quality improvement of kiwifruit.

Fabrication, characterization and biological properties of pectin and/or chitosan-based films incorporated with noni (Morinda citrifolia) fruit extract

Noni ( Morinda citrifolia ) fruit is a natural food source rich in antioxidant and antimicrobial compounds. In this study, the phytochemicals of noni fruit extract (NFE) were identified by using HPLC-ESI-qTOF/MS method. Subsequently, casting method was adopted to prepare pectin and/or chitosan (CH)-based films incorporated with NFE. The influence of NFE addition on the physicochemical, microstructure, and biological properties of pectin and/or CH-based films was evaluated. Results confirmed that incorporation of NFE into pectin and/or CH-based films increased the tensile properties, water vapor permeability (WVP) and opacity of the films, but declined the thickness, moisture content and water solubility slightly. However, pectin-based films showed higher water solubility than CH-based films followed by pectin/CH-based films. In addition, the addition of NFE slightly decreased the film's thermal stability, and CH-based films showed better thermal stability compared to pectin or pectin/CH-based films. Regardless of the NFE addition, no significant morphological changes of pectin and pectin/CH-based films were observed using scanning electron microscopy (SEM). Compared with the control films, the average roughness of CH-based film surface was evidently increased. FTIR results showed that the addition of NFE had no remarkably influences on chemical structures of the films. More importantly, the addition of NFE effectively improved the antioxidant and antibacterial activities of the pectin and/or CH-based films, which was due to phenolic compounds existed in NFE. In short, pectin and/or CH-based films incorporated with NFE is characterized with eco-friendliness, reliability and multiplex bio-activities, which is expected to be a promising alternative for the plastics food packaging film. • Phenolic compositions of noni fruit extract (NFE) were identified by LC-MS/MS. • Pectin and/or chitosan-based edible films incorporated with NFE were fabricated. • Physicochemical properties of the prepared films were investigated and compared. • Incorporated with NFE improved the tensile strength and opacity of the films. • Incorporated with NFE slightly decreased the film's thermal stability. • Incorporated with NFE enhanced antioxidant and antibacterial activities of the films.

Changes of Ca forms and chelate-soluble pectin in cherry tomatoes treated with ultrasound and calcium lactate

The physicochemical properties, polygalacturonase and pectin methylesterase activity, calcium form, and structure of chelate-soluble pectin (CSP) in cherry tomatoes were studied. The total calcium and CSP contents for calcium with ultrasound assisted treatment (U + Ca) group were the highest at the end of storage. U + Ca improved the calcium content from 0.6486 g/kg to 07198 g/kg, and enhanced the permeation of Ca2+ into cell walls. Compared to control (CK), ultrasound (U) and calcium (Ca) groups, the fruit firmness of U + Ca group maintained at high level throughout the storage process. Soluble solids content of all groups had no significant difference at the end of storage. Titratable acidity of cherry tomatoes in U + Ca group was higher than that in CK and U groups at day 30. According to CSP structure analysis, its main configuration had no obvious change at the end of storage. Atomic force microscopy and weight average molecular mass analyses confirmed that U + Ca delayed the degradation of CSP. Our results indicated that U + Ca has application potential in maintaining the quality of cherry tomatoes during storage.

Rhamnogalacturonan Endolyase Family 4 Enzymes: An Update on Their Importance in the Fruit Ripening Process

Fruit ripening is a process that produces fruit with top sensory qualities that are ideal for consumption. For the plant, the final objective is seed dispersal. One of the fruit characteristics observed by consumers is texture, which is related to the ripening and softening of the fruit. Controlled and orchestrated events occur to regulate the expression of genes involved in disassembling and solubilizing the cell wall. Studies have shown that changes in pectins are closely related to the loss of firmness and fruit softening. For this reason, studying the mechanisms and enzymes that act on pectins could help to elucidate the molecular events that occur in the fruit. This paper provides a review of the enzyme rhamnogalacturonan endolyase (RGL; EC 4.2.2.23), which is responsible for cleavage of the pectin rhamnogalacturonan I (RGL-I) between rhamnose (Rha) and galacturonic acid (GalA) through the mechanism of β-elimination during fruit ripening. RGL promotes the loosening and weakening of the cell wall and exposes the backbone of the polysaccharide to the action of other enzymes. Investigations into RGL and its relationship with fruit ripening have reliably demonstrated that this enzyme has an important role in this process.

The receptor kinase OsWAK11 monitors cell wall pectin changes to fine-tune brassinosteroid signaling and regulate cell elongation in rice

Rates of plant cell elongation change with day-night alternation, reflecting differences in metabolism related to cell wall remodeling. Information from cell wall surveillance pathways must be integrated with growth regulation pathways to provide feedback regulation of cell wall modification; such feedback regulation is important to ensure sufficient strength and prevent rupture of the cell wall during growth. Several lines of evidence suggest that cell wall perturbations often influence phytohormone signaling, but the identity of the nexus between these two processes remained elusive. Here, we show that wall-associated kinase11 (OsWAK11) acts as a linker connecting cell wall pectin methyl-esterification changes and brassinosteroid (BR) signaling in rice. Our data show that OsWAK11 controls several important agronomical traits by regulating cell elongation in rice. OsWAK11 directly binds and phosphorylates the BR receptor OsBRI1 at residue Thr752, within a motif conserved across most monocot graminaceous crops, thus hindering OsBRI1 interaction with its co-receptor OsSERK1/OsBAK1 and inhibiting BR signaling. The extracellular domain of OsWAK11 shows a much stronger interaction toward methyl-esterified pectin as compared with de-methyl-esterified pectin. OsWAK11 is stabilized in light but is degraded in darkness, in a process triggered by changes in the ratio of methyl-esterified to de-methyl-esterified pectin, creating fluctuations in plant BR signaling in response to day and night alternation. We conclude that OsWAK11 is a cell wall monitor that regulates cell elongation rates to adapt to the environment from the outside in, which complements the well-established inside-out signaling pathway affecting cell elongation in plants.

Study on textural changes and pectin degradation of tarocco blood Orange during storage

ABSTRACT Pectin degradation in the cell walls and middle lamella greatly affects the texture and the quality of the fruit including the taste and storage time. This directly affects its acceptability, supply to the consumer market, and economic benefits. It is therefore essential to establish the relationship between the chemical changes of pectin and the texture of the fruit to improve its preservation. This study was designed to evaluate the degradation of pectin in the peels of Tarocco blood orange and the textural changes during postharvest storage and further investigate their relationship over the study period. The texture of the fruit was characterized using the texture profile analyzer and the degradation of pectin was investigated by testing the content of the pectin, degree of esterification, and galacturonic acid content. The physicochemical properties, such as weight loss, moisture content, and anthocyanin content were also measured. Furthermore, the structural changes of the pectin were analyzed by molecular weight determination and FTIR test. The results showed that the Mw of pectin decreased from 568.05 kDa to 362.55 kDa, with a 42.1% decline in pectin content for storing for 63 d. The gradual solubilization, depolymerization, and de-esterification of the pectin consequently led to the decline in the textual properties of the fruit during postharvest storage. This can be applied and lead to improvements in quality control and process design in the food industry and the marketplace for the fruit during storage and preservation.

Dynamic changes of pectin epitopes and daylily tepals during flower opening and senescence of Hemerocallis citrina

Ephemeral flower deaths occur within 24 h of flowering in the genus Hemerocallis. The senescence of plant organs is owing to the loss of cell wall cohesion. Pectin is the most structurally complex plant cell wall polysaccharide and has an important role in cell-to-cell adhesion. In this study, we used histological stains, immunolocalization and pectin characterization analyses to examine the dynamic changes in pectin in Hemerocallis citrina ‘Datonghuanghua’ tepals at eight stages (S1–S8). The pectin-specific antibodies JIM5 and JIM7, which hybridize to differently esterified regions of the homogalacturonan (HG) backbone, showed that demethylesterification of HG-type pectins was evident after the outer tepals had opened. Before flower opening, these two antibodies labelled tissue continuously across the cell wall, and the cells were round and tightly packed. The labeling of highly esterified epitopes recognized by JIM7 became deformed when the outer tepals opened. However, 12 h after blooming, low-and high-esterified epitope signals were disrupted near the vascular cylinder, and air space then appeared until these signals disappeared. labeling with the antibody LM5, which is specific for the (1 → 4)-β galactan side chains of rhamnogalacturonan-I, was disrupted near the vascular cylinder at the same stage. Moreover, the contents of neutral sugars in pectin analyses showed that galactose decreased significantly at 12 h after blooming. Three enzymes were involved in pectin remodeling at different developmental phases. The activities of pectin methylesterase continued to increase after the outer tepals opened and reached a significant peak at 12 h after blooming. The activities of polygalacturonase and pectate lyase also increased, but the difference was not significant. Our findings revealed that demethylesterification of HG-type pectins was evident after the outer tepals opened, and this remodeling greatly facilitated their degradation by pectic enzymes. The loss of cell wall material and cohesion that accompanied the activities of pectic enzymes was associated with senescence. Therefore, remodeling of the pectin in cell walls of the tepals is necessary for the occurrence of senescence.

The interfacial covalent bonding of whey protein hydrolysate and pectin under high temperature sterilization: Effect on emulsion stability

In this study, the effect of high-pressure steam sterilization (121 °C for 15 min) on whey protein hydrolysate-pectin solutions and emulsions was studied. The interaction and emulsification characteristics of pectin and whey protein concentrate (WPC) were evaluated from the solution system to the emulsion system. Enzymatic hydrolysis of WPC (WPH, 2 % and 8 % degree of hydrolysis) increased the covalent binding with pectin, which reduced the heat-induced aggregation of protein and improved emulsification. The thermodynamic incompatibility between WPC and pectin was not conducive to the covalent bonding under high temperature sterilization and produced serious aggregates, which also made a rapid increase in particle size (up to ∼3 μm), compared to WPH-pectin emulsion (∼ 400 nm). In addition, if emulsion was stirred during the sterilization, the creaming and protein aggregation could be avoided. By comparing low methoxy pectin (LMP) and high methoxy pectin (HMP), it was found that the whey protein-HMP complex had better emulsification stability, and the steric stabilization played a more important role in emulsion stability than the electrostatic repulsion. The changes of whey protein and pectin at the oil-water interface of the emulsion during the sterilization process may provide a reference for the sterilized bioactive ingredient delivery system.

Microscopic evidence for pectin changes in hard-to-cook development of common beans during storage

In this study, pectin changes during Red haricot bean storage under high temperature and high humidity conditions were investigated to understand the hard-to-cook (HTC) development from a microstructural point of view. First, to ensure repeatability of the microscopy results, a classification of the fresh and stored beans (aged at 35 °C and 83% relative humidity) into different hardening levels (the Non-aged, Aged and Very-hard aged sample) was performed based on the texture values of cooked half-cotyledons. Cell wall strength of the cotyledons was evaluated, showing that the aged samples (HTC seeds) exhibit stronger cell walls with more/stronger pectic cross-linkages than the Non-aged sample. After a sequential pectin extraction aiming at removing pectin fractions of different solubility, cell wall autofluorescence and immunolabeling of JIM7, LM9 and 2F4 epitopes in the residual materials were examined. Upon ageing, the samples exhibited an increased Ca2+-pectin and ferulic acid-pectin crosslinking, these pectic complexes being accumulated primarily at the intercellular spaces. The results suggest a contribution of both the pectin-cation-phytate hypothesis and the involvement of phenolic-pectin crosslinks in HTC development at the cotyledon during storage of common beans.

Differential gene expression of pectin esterase and changes in pectin during development and ripening stages of fruit in selected cultivars of banana

Abstract Pectin is a very important ingredient in food processing. The present study was designed to find out the changes taken place in pectin content during development and ripening phases of banana fruit. The expression of gene (pectin esterase) was also observed during development and ripening. Five exotic cultivars namely William, Brazilian, G-Naine, Basrai and Pisang were selected for this study. Sampling were carried out after every 2 weeks during development and there was 6 sampling stages (from emergence to harvesting stage). After harvesting the fruit of all cultivars were subjected to natural ripening in the lab and sampling during ripening were carried out according to the colour changes in the fruit skin. 5 ripening stages were studied. Hence total number of 11 stages were studied during development and ripening. The sequence of pectin esterase were obtained from NCBI, primers were designed and procured. RNA was extracted from each cultivar and expression analysis of pectin esterase was carried out. It was found that the expression of gene is variable during the development and the ripening stages in each cultivar. Similarly, the pectin content were also significantly variable during development and ripening of fruit. The variation was also found among the cultivars. It was concluded that unripe banana have more pectin content then ripe banana and the pectin content of the fruit is associated with expression of the gene.

Short De-Etiolation Increases the Rooting of VC801 Avocado Rootstock.

Dark-grown (etiolated) branches of many recalcitrant plant species root better than their green counterparts. Here it was hypothesized that changes in cell-wall properties and hormones occurring during etiolation contribute to rooting efficiency. Measurements of chlorophyll, carbohydrate and auxin contents, as well as tissue compression, histological analysis and gene-expression profiles were determined in etiolated and de-etiolated branches of the avocado rootstock VC801. Differences in chlorophyll content and tissue rigidity, and changes in xyloglucan and pectin in cambium and parenchyma cells were found. Interestingly, lignin and sugar contents were similar, suggesting that de-etiolated branches resemble the etiolated ones in this respect. Surprisingly, the branches that underwent short de-etiolation rooted better than the etiolated ones, and only a slight difference in IAA content between the two was observed. Gene-expression profiles revealed an increase in ethylene-responsive transcripts in the etiolated branches, which correlated with enrichment in xyloglucan hydrolases. In contrast, transcripts encoding pectin methylesterase and pectolyases were enriched in the de-etiolated branches. Taken together, it seems that the short de-etiolation period led to fine tuning of the conditions favoring adventitious root formation in terms of auxin–ethylene balance and cell-wall properties.

Characterization of pectin extracted under mild conditions from tempesquistle (Sideroxylon palmeri) fruit at two maturity stages.

le tree (Sideroxylon palmeri) belongs to family Sapotaceae, and its fruits contain hydrophilic and hydrophobic gums. Aim of this study was to develop an extraction method for pectin, a hydrophilic gum, from green and ripe tempesquistle fruit. The extraction method was gentle to minimize potential structural changes in pectin, a maceration was used, and then pectin precipitation was induced with acetone at room temperature. Pectin characterization was carried out in two steps. The first step consisted of qualitative tests of Molisch, Fehling and Lugol. The second step consisted of quantitative tests to determine esterification degree (ED) by ATR-FTIR and D-galacturonic acid (D-GalA) content with a colorimetric assay. ATR-FTIR spectroscopic method revealed that green and ripe tempesquistle fruit have an ED of 0% and 30.4%, respectively. Both fruit have a low ED pectin. The content of D-GalA in green and ripe pectins was 18.8 ±2.7% and 20.2 ±0.6%, respectively. The yield obtained in green and ripe fruit samples was 1.6 ±0.2% and 3.0 ±0.1%, respectively. The extraction method allowed two types of pectins obtained in function of maturity stage of tempesquistle fruit distinguishable by. istle tree (Sideroxylon palmeri) belongs to family Sapotaceae, and its fruits contain hydrophilic and hydrophobic gums. Aim of this study was to develop an extraction method for pectin, a hydrophilic gum, from green and ripe tempesquistle fruit. The extraction method was gentle to minimize potential structural changes in pectin, a maceration was used, and then pectin precipitation was induced with acetone at room temperature. Pectin characterization was carried out in two steps. The first step consisted of qualitative tests of Molisch, Fehling and Lugol. The second step consisted of quantitative tests to determine esterification degree (ED) by ATR-FTIR and D-galacturonic acid (D-GalA) content with a colorimetric assay. ATR-FTIR spectroscopic method revealed that green and ripe tempesquistle fruit have an ED of 0% and 30.4%, respectively. Both fruit have a low ED pectin. The content of D-GalA in green and ripe pectins was 18.8 ±2.7% and 20.2 ±0.6%, respectively. The yield obtained in green and ripe fruit samples was 1.6 ±0.2% and 3.0 ±0.1%, respectively. The extraction method allowed two types of pectins obtained in function of maturity stage of tempesquistle fruit distinguishable by ATR. istle tree (Sideroxylon palmeri) belongs to family Sapotaceae, and its fruits contain hydrophilic and hydrophobic gums. Aim of this study was to develop an extraction method for pectin, a hydrophilic gum, from green and ripe tempesquistle fruit. The extraction method was gentle to minimize potential structural changes in pectin, a maceration was used, and then pectin precipitation was induced with acetone at room temperature. Pectin characterization was carried out in two steps. The first step consisted of qualitative tests of Molisch, Fehling and Lugol. The second step consisted of quantitative tests to determine esterification degree (ED) by ATR-FTIR and D-galacturonic acid (D-GalA) content with a colorimetric assay. ATR-FTIR spectroscopic method revealed that green and ripe tempesquistle fruit have an ED of 0% and 30.4%, respectively. Both fruit have a low ED pectin. The content of D-GalA in green and ripe pectins was 18.8 ±2.7% and 20.2 ±0.6%, respectively. The yield obtained in green and ripe fruit samples was 1.6 ±0.2% and 3.0 ±0.1%, respectively. The extraction method allowed two types of pectins obtained in function of maturity stage of tempesquistle fruit distinguishable by ATR-FTIR.