Properties of amidated pectins. I. Preparation and characterization of amidated pectins and amidated pectic acids

doi:10.1016/S0268-005X(86)80014-5

Food Hydrocolloids

Volume 1, Issue 2, November 1986, Pages 121-127

https://doi.org/10.1016/S0268-005X(86)80014-5 Get rights and content

Abstract

The preparation of high molecular weight pectic acids with varying degrees of amidation (15–61%) is described. The samples are characterized by analytical parameters, viscosity and behaviour on gel permeation and ion-exchange chromatography columns. Results show that the monomer composition is not changed and that aggregation may occur in aqueous solution of highly amidated pectic acids.

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Cited by (23)

Amidation of arabinoglucuronoxylans to modulate their flow behavior
2024, Carbohydrate Polymers
Arabinoglucuronoxylans obtained from the exudate of Cercidium praecox (Brea gum) were subjected to an amidation reaction to modulate their flow behavior to obtain a product with similar behavior to gum Arabic. The amidation reaction of the uronic acids present in this exudate was studied using the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) system with the aim of maximizing product yield and minimizing by-product. An analysis of the significant factors involved in the reaction was carried out and a response surface methodology was conducted to optimize the stoichiometry of the reagents used. It was possible to obtain models for predicting the degree of amidation (DA) of arabinoglucuronoxylans and the formation of by-products. The formation of a secondary product derived from the amino acid β-alanine which has not been reported previously in the reaction with polysaccharides, was described. The flow behavior of an amidated product (DA = 52 %) was determined, showing a pseudoplastic behavior and a decreased Newtonian viscosity (η₀ = 36.2 Pa s) at the lowest shear rate range with respect to native product solution (η₀ = 115 Pa s). Amidated arabinoglucuronoxylans had a flow behavior more similar to that of gum Arabic.
In-situ crosslinked hydrogel based on amidated pectin/oxidized chitosan as potential wound dressing for skin repairing
2021, Carbohydrate Polymers
Citation Excerpt :
AP was synthesized according to the previous study with slight modifications (Reitsma, Thibault, & Pilnik, 1986). In brief, 10 g of pectin was dispersed in a mixture based on 40 mL of 17 M aqueous ammonia and 60 mL of pre-cooled isopropanol solution (Reitsma et al., 1986). The suspension was vigorously stirred in a flask for 24 hrs.
Hydrogel can provide a favorable moisture environment for skin wound healing. In this study, a novel in-situ crosslinked injectable hydrogel was prepared using the water-soluble amidated pectin (AP) and oxidized chitosan (OC) through Schiff-base reaction without any chemical crosslinker. The influence of AP content on the properties of the hydrogel was systemically investigated. It showed that gelation time, pore structure, swelling capability and degradability of the hydrogel can be tuned by varying the content of amine and aldehyde groups from AP and OC. All the porous hydrogels with various AP contents (65%, 70%, and 80%) presented desirable gelation time, swelling property, high hemocompatibility and biocompatibility. Particularly, AP-OC-65 hydrogel presented superior swelling capability and better hemo- and bio-compatibility, owing to more residual amine sites in the hydrogel. Therefore, the injectable AP-OC-65 hydrogel has a greater potential for application to wound dressing or skin substitute.
Pectin as a rheology modifier: Origin, structure, commercial production and rheology
2017, Carbohydrate Polymers
Citation Excerpt :
In this heterogeneous system, the methyl-esterified GalA residues undergo saponification at a slower rate than with sodium hydroxide in water at the same pH. As the time of reaction increases, the DM decreases, DAm increases and the GalA content remains constant (Renard & Thibault, 1996). The neutral sugar composition and number of side chains remain constant (Reitsma, Thibault, & Pilnik, 1986). The molecular weight of ALMPs do not change drastically relative to the initial HMP used, suggesting that the reaction does not lead to drastic de-polymerization under these conditions (Anger & Dongowski, 1988).
Pectins are a diverse family of biopolymers with an anionic polysaccharide backbone of α-1,4-linked d-galacturonic acids in common. They have been widely used as emulsifiers, gelling agents, glazing agents, stabilizers, and/or thickeners in food, pharmaceutical, personal care and polymer products. Commercial pectin is classified as high methoxy pectin (HMP) with a degree of methylation (DM) >50% and low methoxy pectin (LMP) with a DM <50%. Amidated low methoxy pectins (ALMP) can be obtained through aminolysis of HMP. Gelation of HMP occurs by cross-linking through hydrogen bonds and hydrophobic forces between the methyl groups, assisted by a high co-solute concentration and low pH. In contrast, gelation of LMP occurs by the formation of ionic linkages via calcium bridges between two carboxyl groups from two different chains in close proximity, known as the ‘egg-box’ model. Pectin gels exhibit Newtonian behaviour at low shear rates and shear-thinning behaviour when the shear rate is increased. An overview of pectin from its origin to its physicochemical properties is presented in this review.
Preparation and characterization of in situ ionic cross-linked pectin films: Unique biodegradable polymers
2014, Carbohydrate Polymers
Citation Excerpt :
Pectins always contain some associated neutral sugars, typically, l-rhamnose, l-arabinose, d-galactose, d-xylose and d-glucose. These sugars are often linked to the hydroxyl groups on the number 2 and 3 carbons of the main chain (Aspinall, Craig, & Whyte, 1968; Colquhoun, De Ruiter, Schols, & Vorgan, 1990; Darvill, McNeil, Albersheim, & Delmer, 1980; Reitsma, Thibault, & Pilnik, 1986). It is noteworthy that the polygalacturonic acid is partly esterified with methyl groups while the free acid groups maybe partly or fully neutralized with sodium, potassium, or ammonium ions.
The study aimed to investigate the swelling and degradation of calcium pectinate (CaP) films that were cross-linked by the innovative approach of adding aqueous calcium chloride (CaCl₂) to pre-formed pectin films in situ. The films, cast from low methoxy pectin, were dried and cross-linked by immersion in a selected CaCl₂ solution for a selected period. It was found that CaCl₂ concentration, immersion time, and temperature affected the films’ dissolution and swelling behaviors in simulated intestinal fluid. With lower CaCl₂ concentration, more time was needed to form a proper film. Heat accelerated the cross-linking reaction, probably by elevating the cross-linked solution flux into the matrix. Depending upon cross-linking conditions, similar calcium contents in the CaP films resulted in different swelling and degradation behaviors. The degree of pectin esterification (DE) affected the films’ degradation rate. The role of pectin molecular weight and DE on the films’ mechanical properties was determined by stress/strain analysis.
Cross-linking of amidated low-methoxylated pectin with calcium during extrusion/spheronisation: Effect on particle size and shape
2005, Chemical Engineering Science
Citation Excerpt :
Looking closer into the solubility of amidated LM pectins, an apparent contradiction is seen in that the pectin with the highest proportion of methoxyl groups, namely the DA 14 (DM 36%) appears to be the most soluble (Table 2) and therefore least suited for preparation of spherical particles without addition of calcium ions. A low solubility of highly amidated pectin samples in water has been reported earlier (Reitsma et al., 1986), and the phenomenon was ascribed to aggregation. Carbohydrates, especially those containing large numbers of hydroxyl groups, are often thought of as being hydrophilic but it is known that they show more hydrophobic characteristics if they have a large number of internal hydrogen bonds.
Granulation and pelletisation by wet extrusion/spheronisation is a well-known technique for particle design in the pharmaceutical industry. The objective of this study was to evaluate the use of amidated low-methoxylated (LM) pectin as an excipient for pelletisation by extrusion/spheronisation. The influence of degree of amidation of pectin (14%, 18% and 24%) and concentration of added calcium ions (0%, 5%, 12% w/w) on the shape and size of pectin pellets was investigated. The chosen approach was to aim at cross-linking during processing which could be obtained by adding calcium ions to the amidated pectin in the powder mixture and perform granulation/extrusion with water. Addition of calcium ions was expected to reduce the solubility and swelling of pectin during processing, and, consequently, the roundness of the pectin pellets should be improved. Both the degree of amidation and the concentration of added calcium ions as well as the interaction between the two were identified as significant factors in preparation of spherical pellets. The results suggest that the egg-box model alone cannot describe the cross-linking between amidated LM pectin and calcium ions, and it is proposed that the amid group itself plays an important role in the system.
Influence of sodium citrate and potassium-sodium tartrate on gelation of low-methoxyl amidated pectin
2003, Journal of Food Engineering
The influence of sodium citrate and potassium–sodium tartrate on Ca²⁺ induced low-methoxyl amidated pectin gelation has been investigated. Dispersions with pectin concentration 1%, soluble solids (sucrose) 30% and pH 4 have been prepared. The measurements have been performed with a HAAKE VT 550 viscotester. The range of Ca²⁺ concentrations at which “good” gels can be formed is very narrow in cases when gels have been prepared without salt or when NaCl has been used. This range is expanded and shifted to larger Ca²⁺ concentration in the presence of sodium citrate and potassium–sodium tartrate. These salts “weaken” the gels (module of elasticity G and rupture stress τ₀ decrease with increasing salt’s concentration) and make them more elastic (rupture strain γ₀ increases). The effect of the above-mentioned salts on gel restoring after mechanical destruction (shearing) or melting has been investigated. Both salts make regelling significantly difficult in the case when the gels have been mechanically destroyed. Gels become thermoreversible (they can be melted) and their restoration after melting depends on the salt’s concentration.

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Properties of amidated pectins. I. Preparation and characterization of amidated pectins and amidated pectic acids

Abstract

Anal. Biochem.

Acid amides of pectinic acid and process for their preparation

Method for producing pectins having high resistance to breakage and high capacity for gelling in the presence of calcium

Slow-set pectin and process for preparing same

Intermediate amide pectins

Food Technol.

Food Technol

Die Nahrung

J. Food Sci.

The chemical and rheological properties of low-ester pectin gels