Gelation alginate-pectin

Alginate-pectin gelation will be presented as an example for which the formation of junction zones has been proposed to involve two chemically different but geometrically complementary polymer molecules. Pectin is the structural polysaccharide in plants equivalent to alginate in brown seaweed. The term pectin covers a wide range of... 

Pectins are generally classed according to their ester content as high methoxyl pectins (>50% of the carboxyl groups esterified) or low methoxyl pectins (<50% of carboxyl groups esterified) (pectic acid, methyl ester [9049-34-1]). Low methoxyl pectins, like algins, require calcium for gelation. 

Toft, K., Grasdalen, H., and Smidsrod, O. (1986). Synergistic gelation of alginates and pectins. In Chemistry and Function of Pectins, ACS Symposium Series 310, pp. 117-132. Am. Chem. Soc., Washington, DC. 

Substantial research efforts have been made to relate molecular properties to the structures of the junction zones and provide mechanisms for gel formation. Thus we have models for the formation and alignment of double helices for kappa-carrageenan, formation of triple helices for gelatin and egg box models for calcium induced gelation of alginate and pectin to mention a few examples (Morris 1986 Djabourov... 

Rao, M. A. and Cooley, H. J. 1995. Rates of structure development during gelation and softening of high-methoxyl pectin-sodium alginate-fructose mixtures. Food Hydrocolloids 9 229-235. 

Braccini 1, Perez S (2001) Molecular basis of Ca 2-l-induced gelation in alginates and pectins the egg-box model revisited. Biomacromolecules 2 1089-1096... 

Polyelectrolyte, Carbox5methylcellulose, Pectin, Carrageenan, Alginate, Cationic starch, Galactomannan, Lignosulphonate, Ion exchange. Conformational transition. Physical gelation. Electrostatic complex, Chitosan... 

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