Effects of Calcium, pH, and Blockiness on Kinetic Rheological Behavior and Microstructure of HM Pectin Gels
Artikel i vetenskaplig tidskrift, 2005

The kinetic behavior during gel formation and the microstructure of 0.75% high methoxyl (HM) pectin gels in 60% sucrose have been investigated by oscillatory measurements and transmission electron microscopy for three comparable citrus pectin samples differing in their degree of blockiness (DB). Ca2+ addition at pH 3.0 resulted in faster gel formation and a lower storage modulus after 3 h for gels of the blockwise pectin A. For gels of the randomly esterified pectin B, the Ca2+ addition resulted in faster gel formation and a higher storage modulus at pH 3.0. At pH 3.5, both pectins A and B were reinforced by the addition of Ca2+. In the absence of Ca2+, the shortest gelation time was obtained for the sample with the highest DB. Microstructural characterization of the gel network, 4 and 20 h after gel preparation, showed no visible changes on a nanometer scale. The microstructure of pectins A and B without Ca2+ was similar, whereas the presence of Ca2+ in pectin A resulted in an inhomogeneous structure.


Caroline E E Löfgren

Chalmers, Kemi- och bioteknik, Livsvetenskaper

Stephanie Guillotin

Hanne Evenbratt

Chalmers, Kemi- och bioteknik, Farmaceutisk teknologi

Henk Schols

Anne-Marie Hermansson

Chalmers, Kemi- och bioteknik, Livsvetenskaper


1525-7797 (ISSN) 1526-4602 (eISSN)

Vol. 6 2 646-652





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