Toward the Recognition of Structure-Function Relationships in Galactomannans

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• 作者：Piet J. H. Daas ; Katja Grolle ; Ton van Vliet ; Henk A. Schols ; and Harmen H. J. de Jongh
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2002
• 出版时间：July 17, 2002
• 年：2002
• 卷：50
• 期：15
• 页码：4282 - 4289
• 全文大小：98K
• 年卷期：v.50,no.15(July 17, 2002)
• ISSN：1520-5118

文摘

In this paper the determination of the physical/rheological characteristics is described for a series ofcommercial galactomannans of which the structural details have been reported previously. Bothsolubility of the galactomannans and rheological properties of galactomannan solutions andgalactomannan/xanthan mixtures were determined. Using a statistical analysis approach an attemptwas undertaken to recognize correlations between structural and rheological data. The best correlationfound was between the abundance of galactose substituents at a regular distance (type ofgalactomannan) and the storage modulus (G') of mixed galactomannan/xanthan gels, underscoringthe hypothesis that branching hinders the formation of a network with xanthan gum. Also, the G' forthe group of locust bean gums correlated with the degree of blockiness, that is, the size and occurrenceof nonsubstituted regions on the mannose backbone. In addition, galactomannans displayed anapparent decrease in gelling ability with increasing average molecular weight. That G' also relates tothe type of galactomannan can therefore partly be attributed to differences in average molecularweight for the various galactomannan types. However, within the series of locust bean gums tested,also an increase of G' with molecular weight was observed. This can be explained by the decreasingnumber of loose ends of the polymers and the concomitant increasing efficiency in network participationwith increasing molecular weight.Keywords: Guar; locust bean; tara; galactomannans; gums; polymers; structure-function relationship