title: The effect of degradation on κ-carrageenan/locust bean gum/konjac glucomannan gels at acidic pH.
abstract: The feasibility of textural and rheological modification of gels containing κ-carrageenan (KC) and locust bean gum (LBG) by addition of konjac glucomannan (KGM) was investigated. Special attention was paid to the effect of polysaccharide degradation during heating at acidic pH. The general effect of polysaccharide degradation was to decrease the Young's modulus, while the fracture strain in extension was scarcely affected unless the degradation was very severe. Differential scanning calorimetry showed that the melting peak corresponding to dissociation of KC-KGM bonds decreased faster than the melting peak of KC-only bonds with increasing degree of polysaccharide degradation. The implication is that as degradation proceeds, fewer KGM molecules can interact with KC to form elastic bonds, and the excess of KGM which reinforces the existing elastic network and increases the fracture strain actually increases. For this reason, the fracture strain remains nearly unchanged with increasing degradation levels. A decrease in fracture strain is thus observed only at very severe degradations, where KC no longer forms a self-supporting gel by itself.
authors.affiliation: Department of Physics, Zhengzhou University of Light Industry, Zhengzhou, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Yang
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wang
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Nakajima
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Nishinari
authors.forename: Tom
authors.initials: T
authors.lastname: Brenner
mesh_terms: D002351:Carrageenan / Q000737:chemistry*; D055119:Elastic Modulus; D005685:Galactans / Q000737:chemistry*; D005782:Gels; D006863:Hydrogen-Ion Concentration; D008351:Mannans / Q000737:chemistry*; D053149:Plant Gums / Q000737:chemistry*; D012212:Rheology; D013696:Temperature
chemical_list: D005685:Galactans; D005782:Gels; D008351:Mannans; D053149:Plant Gums; C022901:(1-6)-alpha-glucomannan; D002351:Carrageenan; C017471:locust bean gum
keywords: Konjac glucomannan; Locust bean gum; Mixed gels; Polysaccharide degradation; κ-Carrageenan