Global hydrodynamic analysis of the molecular flexibility of galactomannans

• Published in: Carbohydrate polymers 2008-05, Vol.72 (2), p.356-360
• Main Authors: Morris, Gordon A., Patel, Trushar R., Picout, David R., Ross-Murphy, Simon B., Ortega, Alvaro, Garcia de la Torre, Jose, Harding, Stephen E.
• Format: Article
• Language: English
• Subjects: algorithms; Applied sciences; biopolymers; chemical structure; computer analysis; equations; Exact sciences and technology; Galactomannan; galactomannans; Guar; guar gum; LBG; locust bean gum; Mass per unit length; Natural polymers; Persistence length; Physicochemistry of polymers; rheological properties; rheology; sedimentation coefficient; Semi-flexible coil; Starch and polysaccharides; viscosity; Worm-like chain
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2007.08.017

In the past, intrinsic viscosity and sedimentation velocity analyses have been used separately to assess the conformation and flexibility of guar and locust bean gum galactomannans based on worm-like chain and semi-flexible coil models. Publication of a new global method combining data sets of both intrinsic viscosity and sedimentation coefficient with molecular weight, and minimising a target (error) function now permits a more robust analysis. Using this approach, values for the persistence length of (10 ± 2) nm for guar and (7 ± 1) nm for locust bean gum are returned if the mass per unit length M L is floated as a variable. Using a fixed mass per unit length based on the known compositional data of each galactomannan yields a similar value for L p in both cases, (8 ± 1) nm for guar and (9 ± 1) nm for locust bean gum, with combined set of data yielding (9 ± 1) nm: within experimental error the flexibilities of both galactomannans are very similar.