Types Of Pectins Research Articles

Dynamic changes in the chemical structure and gelling properties of pectin at different stages of citrus maturation and storage

Citrus pectins (CP) are the most common types of commercial pectins, and their gelling properties are of interest in many industrial applications. However, the dynamic changes in the chemical structures and gelling properties of pectins during citrus maturation and storage are poorly understood. This study compared pectins from citrus fruit in terms of different maturity (M1: green citrus; M2: green-yellow citrus; M3: light orange citrus; FM: full maturity citrus) and storage times (S1: 10-day; S2: 20-day; S3: 30-day). All pectin were high-methoxylated polymers, with high content of HG and RG-I domain (about 95.0 mol%). With increasing citrus maturity and storage time, HG content (from 69.0 mol% to 51.9 mol%), the molecular weight and methyl-esterification of pectins continuously decreased, while the RG-I content (from 26.4 mol% to 42.5 mol%) and compact spatial conformation significantly increased. Polygalacturonase, methylesterase, α-arabinofuranosidase, β-galactosidase, and cellulase, induced dynamic variations in the structural characteristics of pectins. The decreases in HG content and the lower molecular weight reduced hydrogen bonding and the hydrophobic interactions, thus weakening the gelling properties. The relatively high RG-I content, the additional hydrogen bonds generated by the free carboxyl groups, and the compact conformation shortened the distances between pectin chains and increased chain entanglement, thereby ensuring that the gel network was stable. Consequently, CPS3 gel exhibited the greatest strength (hardness: 977.0 g, Aα: 642.9 Pa sα) and satisfactory extrusion recovery ability (springiness: 95.5%). These results can guide the selection of raw materials that will yield pectins with specific structural characteristics and superior gelling properties.

Effect of different types of pectin on the physicochemical, rheology, and sensory properties of low-fat yogurt

Abstract Low-fat yogurt has been defined to contain fat content of not more than 2.0 percent as per The Code of Federal Regulations, FDA, U.S. Nevertheless, the reduced fat content affects the physicochemical properties of yogurt by weakened texture, poor body, syneresis, and sensory quality. This is due to fat globules that govern the protein linkages that are responsible for the yogurt’s texture and firmness. The objectives of this study are to evaluate the physicochemical, rheology properties, and to determine the sensory properties and overall acceptability of low-fat yogurt enriched with different types of pectin. Pectin helps improve the gel characteristics, rheology, and microstructure of set yogurt through interactions with the casein network. Two different types of pectins are used which are low-methoxyl pectin (LMP) and high-methoxyl pectin (HMP). For each type, two different concentrations were used which are 0.5% and 1.0% for both types of pectin. Analysis such as pH measurement, titrable acidity, color measurement, water holding capacity measurement, syneresis measurement, viscosity measurement, microbial analysis, and scanning electron microscopy were conducted. The results from the analysis above were subjected to two-way ANOVA and post hoc Tukey’s test. The addition of LMP (0.5% and 1.0%) showed a positive effect on the quality of yogurt with primary attributes compared to the pectin added with HMP and control sample. In conclusion, the low-fat yogurt had a positive effect due to the enrichment of the pectin. Sample 4 which is the low-fat yogurt with 1.0% of LMP showed better properties compared to other samples.

Application of coffee pulp-derived pectins as a novel coating spray to mitigate Paramyrothecium breviseta, an etiological agent inducing leaf spot disease in coffee

Coffee pulp is a significant byproduct of wet processing and poses ecological risks by contributing to soil acidification and diminished fertility in local ecosystems. Despite its potential environmental impact, coffee pulp is rich in various components, including valuable polysaccharides. This study focuses on extracting pectin from coffee pulp using HCl/KCl and ammonium oxalate. The total yield achieved was approximately 11 %, encompassing distinct types of pectins: Acidic coffee pulp pectin (ACPP) and basidic coffee pulp pectin (BCPP), which represent high and low methoxylate forms, respectively. The fabrication of the pectin (1 %) coating agent was accomplished by combining it with chitosan to form a polyelectrolyte complex (1 %) in a ratio of 10:1. The coffee pulp polyphenols fraction (CPPF), was embedded in the agent at 0.5 g/mL and characterised for inhibiting Paramyrothecium breviseta, a pathogen causing leaf spot in coffee. Experimental results demonstrated that the coating spray, derived from coated ACPP and coated CPPF exhibited the highest efficacy in inhibiting P. breviseta at distances of 0.00 and 1.70 cm on day 16, respectively. This efficacy was significantly different from both the negative control (7.40 cm) and the positive control (4.30 cm). This research highlights the potential of utilising coffee pulp as a valuable resource for pectin extraction and underscores the effectiveness of a formulated coating spray in mitigating the impact of the leaf spot-causing pathogen. The findings contribute to sustainable practices in coffee waste management while presenting a promising approach for plant disease control in coffee cultivation.

Understanding structure/rheology relationships of amidated low-methoxyl citrus and apple pectin gels: Implications of sucrose, pectin types and characteristics

In this study, the relationships between structure and rheology (at small and large deformations) of amidated low-methoxyl (LMA) citrus and apple pectin gels were investigated considering how does these relationships can be modulated by soluble solids (sucrose), pectin types and characteristics. For that purpose, various LMA pectins with varying degrees of methyl esterification (DE) and amidation (DA), processed from citrus peels and apple pomace, were used. Scaling models of biopolymer gels have been critically discussed in respect to pectin critical gelling concentration (C0) and their structural variabilities. It was demonstrated that, whatever the types of LMA pectins and their structural variabilities, scalar percolation and quadratic models can be efficiently used for the prediction of the storage modulus G′ and C0 as other biopolymer gels. Fractal approach reveals that the origin of the LMA pectin gel elasticity is more in harmony with an enthalpic network of rod-like filaments with bending rigidity ruling the network's elasticity. The addition of sucrose induced an anticipation of the gelation temperature and an important improvement of the viscoelastic properties of the resulting gels. It was also shown that the most tough gels are obtained for citrus pectins due to the higher level of neutral sugar side chains in apple pectins that can hinder preponderant ca-bridging sites unlike citrus pectins. Finally, it was shown that unlike the firmness and hardness of the gels which appear to be more driven by the amide groups, the deformability of the gels is rather governed by the methyl ester groups.

Age-related effects on the modulation of gut microbiota by pectins and their derivatives: an in vitro study.

The present study investigates whether supplementation with pectin-type polysaccharides has potential to improve aging-associated dysbiosis of the gut microbiota. The influence of different types of pectins on the gut microbiota composition and short-chain fatty acids (SCFAs) profiles of elderly was compared to younger adults. Pectins studied included a pectin polysaccharide (PEC), a partially hydrolyzed pectin (PPH), and a pectin oligosaccharide (POS). Additionally, inulin was used as a reference prebiotic substrate. Individual fecal samples were collected from healthy elderly volunteers (70-75 years) and younger adults (30-35 years). In vitro fermentations were performed using the CoMiniGut model with controlled temperature and pH. Samples were withdrawn at baseline and after 24 h fermentation for measurement of SCFAs production and microbiota composition by 16S rRNA gene sequencing. The results showed that fermentations with PEC and PPH resulted in a specific stimulation of Faecalibacterium prausnitzii regardless of the age groups. Collinsella aerofaciens became a dominating species in the young adult group with fermentations of all three pectins, which was not observed in the elderly group. No significant differences in SCFAs production were found among the pectins, indicating a high level of functional redundancy. Pectins boosted various bacterial groups differently from the reference prebiotic substrate (inulin). We also found inulin had reduced butyrogenic and bifidogenic effects in the elderly group compared to the younger adult group. In conclusion, the in vitro modulating effects of pectins on elderly gut microbiota showed potential of using pectins to improve age-related dysbiosis.

Effect of different processing methods of hawthorn on the properties and emulsification performance of hawthorn pectin

Five types of hawthorns were obtained using hot air drying (HH), vacuum freeze-drying (FH), Parched processing (PH), Charred processing (CH), and blackening (BH). Five types of pectins (HHP, FHP, PHP, CHP, BHP) were extracted and characterized based on a series of characterization methods. The results indicated that the esterification and molecular weight of BHP were the lowest, which were 30.92 % and 73.67 × 103 (g/mol), respectively. FHP had the highest apparent viscosity and molecular weight (464.42 × 103 g/mol). PHP and CHP differ in galacturonic acid, molecular weight, and monosaccharide composition depending on the time of processing. The emulsion of HHP had the best stability, and the emulsification properties of FHP, PHP, and CHP also showed better performance compared to BHP. In conclusion, our results showed that different processing methods of hawthorn affected the physicochemical properties of pectin, and pectin with specific properties could be obtained by choosing the appropriate processing method.

Pectin with various degrees of esterification differentially alters gut microbiota and metabolome of healthy adults

AbstractPectin with various degrees of esterification (DE) leads to different food processing directions and has the distinct potential for modulating human health. Investigations of pectin–gut microbiota interactions may contribute towards better understanding of the structure–function mechanism. In this study, in vitro batch fermentation (artificial colon model) was used to illustrate the differential impacts of pectin with different DE on the gut microbiota and metabolome of healthy adults. The results indicated that low‐esterified pectin L13 showed better‐sustained abilities in terms of the diversity of microbiota and promoted the abundance of Clostridiaceae and Lachnospiraceae at family levels, and Bacteroides and Lachnospira at genus levels. High‐esterified pectin H121 induced less Enterococcus and Clostridium. Data from untargeted metabolomics revealed the alterations of intracellular metabolites including fatty acids, amino acids, and organic molecules by various types of pectins. Inositol was the unique intracellular metabolite that was significantly upregulated by low‐esterified pectin L13. All types of pectins could increase the level of acetic acid, but butyric acid was only enriched by pectin L13.

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.

Potential of Pectins to Beneficially Modulate the Gut Microbiota Depends on Their Structural Properties.

Pectins are plant cell-wall polysaccharides which can be utilized by commensal bacteria in the gut, exhibiting beneficial properties for the host. Knowledge of the impact of pectins on intestinal bacterial communities is insufficient and limited to a few types of pectins. This study characterized the relationship between the structural properties of pectins and their potential to modulate composition and activity of the gut microbiota in a beneficial way. For this purpose we performed in vitro fermentations of nine structurally diverse pectins from citrus fruits and sugar beet, and a pectic derivative, rhamnogalacturonan I (RGI), using a TIM-2 colon model. The composition of microbiota during TIM-2 fermentations was assessed by 16S rRNA gene amplicon sequencing. Both general and pectin-specific changes were observed in relative abundances of numerous bacterial taxa in a time-dependent way. Bacterial populations associated with human health, such as Faecalibacterium prausnitzii, Coprococcus, Ruminococcus, Dorea, Blautia, Oscillospira, Sutterella, Bifidobacterium, Christensenellaceae, Prevotella copri, and Bacteroides spp. were either increased or decreased depending on the substrate, suggesting that these bacteria can be controlled using structurally different pectins. The main structural features linked to the pectin-mediated shifts in microbiota included degree of esterification, composition of neutral sugars, distribution of homogalacturonan and rhamnogalacturonan fractions, degree of branching, and the presence of amide groups. Cumulative production of the total short chain fatty acids and propionate was largest in fermentations of the high methoxyl pectins. Thus, this study indicates that microbial communities in the gut can be specifically modulated by pectins and identifies the features in pectin molecules linked to microbial alterations. This knowledge can be used to define preferred dietary pectins, targeting beneficial bacteria, and favoring more balanced microbiota communities in the gut.

Study of chemical characteristics, gelation properties and biological application of calcium pectate prepared using apple or citrus pectin

The most notable and unique property of pectin is the ability to form gel; thus, many biological applications of pectin are based on its gelation properties. Pectin isolated from different plant cell walls may differ in molecular structure and distribution pattern, which may result in different gelling and function properties. In this work, we investigated the chemical characteristics, gelation properties, and biological application of calcium pectate (CaP) prepared using apple (AP) or citrus pectin (CP). These two types of pectins exhibited similar molecular parameters and glycosidic bone structure; however, there was a difference in the composition proportion of single monosaccharide. In addition, it was found that it was relatively easier to form CaP beads with CP compared with AP. Moreover, CP exhibited a higher binding capability with Ca2+. The morphological study suggests that CP-CaP beads have a rough wrinkle structure on the surface, which might benefit mass transfer and cell proliferation. Moreover, although there are some differences in the viability and proliferation of cells encapsulated in the AP-CaP and CP-CaP beads, both can be used for cell encapsulation.

Effects of pectin supplementation on the fermentation patterns of different structural carbohydrates in rats

We aimed to investigate and compare the effects of four types of pectins on dietary fiber (DF) fermentation, microbiota composition, and short chain fatty acid (SCFA) production throughout the large intestine in rats. Male Wistar rats were given diets supplemented with or without 3% structurally different pectins for 7 weeks. Different fermentation patterns of pectins and different location of fermentation of pectin and diet arabinoxylans (AXs) in the large intestine were observed. During cecal fermentation, sugar beet pectin significantly stimulated Lactobacillus (p < 0.01) and Lachnospiraceae (p < 0.05). The stimulating effects of sugar beet pectin on these two groups of microbes are stronger than both other pectins. In the cecum, low-methyl esterified citrus pectin and complex soy pectin increased (p < 0.05) the production of total SCFAs, propionate and butyrate, whereas high-methyl esterified pectin and sugar beet pectin did not. The fermentation patterns of cereal AXs in the cecum were significantly different upon supplementation of different pectins. These differences, however, became smaller in the colon due to an enhanced fermentation of the remaining DFs. Dietary supplementation of pectin is a potential strategy to modulate the location of fermentation of DFs, and consequently microbiota composition and SCFA production for health-promoting effects.

Effect of pectin on the composition, microbiology, texture, and functionality of reduced-fat Cheddar cheese

Hydrocolloids have been extensively studied in low-fat cheeses as a way to improve defects associated with fat reduction, which are often related to texture and functionality (meltability). Pectin is a polysaccharide obtained from plant cells and is commonly used as a stabilizer for acidified dairy beverages. This work aimed to evaluate the effect of three types of commercial pectins on the characteristics of reduced-fat Cheddar cheese during a ripening period of 180 days. Five Cheddar cheeses were made: full-fat control (FF), reduced-fat control (RF), and reduced-fat cheeses with amidated (RA), high-methoxy (RH), or low-methoxy (RL) pectin added to milk prior processing at concentrations of 0.175%, 0.100%, and 0.075% (w/w), respectively; levels were chosen to avoid phase separation of the casein micelles, due to depletion flocculation. Addition of amidated pectin markedly increased the moisture content of the experimental cheese (~49%), compared to RF (~45%; P 100 N in RF at 180 days; P 85 versus <70% at 180 days; P < 0.05). These results suggest that pectin addition can be used to modify the moisture content, texture, and melting properties of reduced-fat Cheddar cheese.

Effects of amidation and/or methylesterification of pectin on aroma release at different calcium concentration

Four different types of low methoxyl pectins (LMPs) were prepared via amidation and methylesterification to investigate the release of 14 aroma compounds from different pectin gel systems at different calcium concentration. The release of aroma compounds was determined using static headspace gas chromatography analysis. Amidation and amidation combined by methylesterification increased aroma release from LMP gels compared to the non-treated ones at diverse calcium concentration, except amidated LMP at 0.09% calcium. On the other hand, methylesterified LMP reduced the release of most aroma compounds at 0.03–0.09% calcium concentration. Furthermore, treatment with pectin methylesterase increased the release of aroma compounds from amidated pectin but reduced their release from nonamidated pectin. Comparison of the release of a series of esters with different numbers of carbon atoms revealed increased release of compounds with up to six carbons, and then a decrease of those with up to ten in LMP, amidated LMP, and amidated and methylesterified pectin gel systems.

How cell wall complexity influences saccharification efficiency inMiscanthus sinensis

The production of bioenergy from grasses has been developing quickly during the last decade, with Miscanthus being among the most important choices for production of bioethanol. However, one of the key barriers to producing bioethanol is the lack of information about cell wall structure. Cell walls are thought to display compositional differences that lead to emergence of a very high level of complexity, resulting in great diversity in cell wall architectures. In this work, a set of different techniques was used to access the complexity of cell walls of different genotypes of Miscanthus sinensis in order to understand how they interfere with saccharification efficiency. Three genotypes of M. sinensis displaying different patterns of correlation between lignin content and saccharification efficiency were subjected to cell wall analysis by quantitative/qualitative analytical techniques such as monosaccharide composition, oligosaccharide profiling, and glycome profiling. When saccharification efficiency was correlated negatively with lignin, the structural features of arabinoxylan and xyloglucan were found to contribute positively to hydrolysis. In the absence of such correlation, different types of pectins, and some mannans contributed to saccharification efficiency. Different genotypes of M. sinensis were shown to display distinct interactions among their cell wall components, which seem to influence cell wall hydrolysis.

Chemical characterization and complement fixation of pectins from Cola cordifolia leaves

Defatted leaves from the medicinal tree Cola cordifolia were extracted with 50% EtOH, 50°C and 100°C water. The polysaccharide rich extracts were fractionated and the structure of the polysaccharides elucidated. Linkage analysis of the polysaccharides indicates a rhamnogalacturonan type I backbone where both Rha and parts of GalA are substituted in position 3, indicating a highly branched polymer with short side chains. The purified fractions were tested for complement fixation, macrophage stimulating activity and anti-adhesion activity towards Helicobacter pylori. Here we report on complex and polydisperse types of pectins (Mw: 3–1300kDa) as well as the presence of low Mw (<3kDa) acidic oligosaccharides. The fractions showed a moderate complement fixing activity and no macrophage activating effects after LPS removal. Anti-adhesion activity towards H. pylori was not found.

Colour and stability assessment of blue ferric anthocyanin chelates in liquid pectin-stabilised model systems

The formation of blue coloured ferric anthocyanin chelates and their colour stability during storage and thermal treatment were monitored in a pH range relevant to food (3.6–5.0). Liquid model systems were composed of different types of Citrus pectins, juices (J) and the respective phenolic extracts (E) from elderberry (EB), black currant (BC), red cabbage (RC) and purple carrot (PC) in the presence of ferric ions. For EB, BC and PC, pure blue colours devoid of a violet tint were exclusively observed for the phenolic extracts and at pH values ⩾4.5 in model systems containing high methoxylated and amidated pectins, respectively. Colour and its stability strongly depended on the amount of ferric ions and the plant source; however, colour decay could generally be described as a pseudo-first-order kinetics. Despite optimal colour hues for RC-E and RC-J, storage and heat stabilities were poor. Highest colour intensities and best stabilities were observed for model systems containing PC-E at a molar anthocyanin:ferric ion ratio of 1:2. Ascorbic and lactic acids interfered with ferric ions, thus significantly affecting blue colour evolution and stability. Colour loss strongly depended on heat exposure with activation energies ranging between 60.5 and 78.4kJ/mol. The comprehensive evaluation of the interrelationship of pigment source, pH conditions and pectin type on chelate formation and stability demonstrated that ferric anthocyanin chelates are promising natural blue food colourants.

The cell wall-associated kinases, WAKs, as pectin receptors

The wall-associated kinases, WAKs, are encoded by five highly similar genes clustered in a 30-kb locus in Arabidopsis. These receptor-like proteins contain a cytoplasmic serine threonine kinase, a transmembrane domain, and a less conserved region that is bound to the cell wall and contains a series of epidermal growth factor repeats. Evidence is emerging that WAKs serve as pectin receptors, for both short oligogalacturonic acid fragments generated during pathogen exposure or wounding, and for longer pectins resident in native cell walls. This ability to bind and respond to several types of pectins correlates with a demonstrated role for WAKs in both the pathogen response and cell expansion during plant development.

Pectins as Breadmaking Additives: Effect on Dough Rheology and Bread Quality

The effect of two types of pectins with different degrees of esterification on dough and bread characteristics was analysed. A high methoxyl pectin (HMP) and a low methoxyl pectin (LMP) were assayed in dough without or with salt (2%) at levels ranging from 0.25% to 2.0%. Farinographic water absorption increased when pectins were incorporated in dough with salt, whereas this effect was not observed in dough without salt. Pectin addition diminished the stability of dough in all cases. Texture profile analysis showed that pectins softened the dough, particularly when salt was added. Cohesiveness was also higher in doughs with salt at the maximum level of hydrocolloid addition. In dough with salt, HMP decreased the elastic and viscous moduli, while the values for tan (δ) were increased with respect to control. SEM micrographs showed that dough with pectin has a filamentous structure. In the breadmaking process, dough with HMP showed a better performance, leading to higher specific volumes and softer crumbs both in fresh and stored bread.

Molecular differences of low methoxy pectins induced by pectin methyl esterase I: Effects on texture, release and perception of aroma in gel systems

Six types of low methoxy pectins (two commercial and four modified pectins treated with pectin methyl esterase from Valencia orange) with different degrees of esterification (DE), molecular weights (MW), and degrees of amidation were prepared. Pectin gels containing five aroma compounds were produced and their texture properties, release of aromas, and sensory flavour intensities were investigated. Regarding the gels made with lower MW pectins (<2.1 × 10 5), only headspace concentration of isoamyl acetate was increased, according to the de-esterification of the pectins. In the pectin gels of higher MW (>3.7 × 10 5), however, significantly higher concentrations of aromas in the headspace were shown in the gel with DE value of 6 than the gel with DE value of 40. Perceived flavour intensity was highest in the pectin gel with higher DE (∼40) and lower MW. The sensory texture analysis indicated that the pectin methyl esterase-modified pectin gels had increased hardness, coarseness of mass, springiness, and chewiness. The perceived flavour intensities of the gels showed strong negative correlations with firmness.

On the water-sorption properties of pectin

In this work we investigate the water-sorption isotherms of three types of pectins (from apple, citrus and sunflower) at 25 °C, 35 °C and 45 °C through the classical gravimetric method. The experimental data are treated with BET and GAB model equations for finding the monolayer moisture content X w , a , BET and Guggenheim constants. The investigated pectins were characterized by their X-ray and infrared spectra and an attempt was made to correlate between their water-sorption properties and their molecular structure and crystal organization.