Structure-Related Gelling of Pectins and Linking with Other Natural Compounds: A Review

Abstract

Pectins are polysaccharides present commonly in dicotyledonous and non-grass monocotyledonous plants. Depending on the source, pectins may vary in molecular size, degrees of acetylation and methylation and contents of galacturonic acid and neutral sugar residues. Therefore, pectins demonstrate versatile gelling properties and are capable of forming complexes with other natural compounds, and as a result, they are useful for designing food products. This review focuses on the structure-related mechanisms of pectin gelling and linking with other natural compounds such as cellulose, hemicellulose, ferulic acid, proteins, starch, and chitosan. For each system, optimal conditions for obtaining useful functionality for food design are described. This review strongly recommends that pectins, as a natural biocomponent, should be the focus for both the food industry and the bioeconomy since pectins are abundant in fruits and may also be extracted from cell walls in a similar way to cellulose and hemicellulose. However, due to the complexity of the pectin family and the dynamic structural changes during plant organ development, a more intensive study of their structure-related properties is necessary. Fractioning using different solvents at well-defined development stages and an in-depth study of the molecular structure and properties within each fraction and stage, is one possible way to proceed with the investigation.

Cross-Linking of Wheat Bran Arabinoxylan by Fungal Laccases Yields Firm Gels

“…Nonetheless, as shown in Table 2, it did not have a significant impact on the viscoelastic properties of AX gels. Overall, addition of pectin resulted in hydrogen bonds and hydrophobic interactions in the gel, instead of increasing covalently cross-linked bonds [43]. To sum up, the investigated mediators were not successful in improving the rheological properties of cross-linked AX gel.…”

Cross-Linking of Fibrex Gel by Fungal Laccase: Gel Rheological and Structural Characteristics

“…Although citrus pectin is known as a common thickening and gelling agent to link with various compounds to form a gel [31], it did not significantly affect the rheological properties of fibrex gels ( Table 1). It appeared that the addition of pectin resulted in hydrogen bonds and hydrophobic interactions in the gel, instead of increasing covalently cross-linked bonds [8].…”

“…Feruloyl substitutions can be cross-linked through oxidative coupling reaction ( Figure 1) [6,7]. Recently, 8-5 and 8-O-4 were noted as the main ferulate dehydrodimers in covalently cross-linked structures in gelled sugar beet pectin [8]. Various oxidative agents were applied for the cross-linking of sugar beet pectin gels, including hydrogen peroxide, manganese peroxidases and laccases [9].…”

Tailoring Gelation Mechanisms for Advanced Hydrogel Applications

“…[24] Alternatively, trivalent cations (e.g., Al 3+ , Fe 3+ ) can interact with three carboxylate groups to form a more compact network, generating metal-alginate hydrogels with improved mechanical properties. [25] Other biopolymers capable of forming ionically crosslinked hydrogels include chitosan, [26] pectin, [27] cellulose, [28] and sodium polygalacturonate. [29] Hydrogels can also be generated via coacervation, the liquidliquid phase separation of oppositely charged polymers in an aqueous medium, a process that is predominantly driven by electrostatic interactions.…”