Exothermic events on heating of semi-dilute konjac glucomannan-water systems

• Published in: Carbohydrate polymers Vol. 61; no. 3; pp. 368 - 373
• Main Authors: Karim, A.A., Chang, Y.P., Norziah, M.H., Ariffin, F., Nadiha, M.Z., Seow, C.C.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 29.08.2005; Elsevier Science
• Subjects: annealing; Applied sciences; aqueous solutions; enthalpy; Exact sciences and technology; Exothermic transitions; gelation; glucomannans; heat stability; heat treatment; Konjac glucomannan; konjac mannan; Natural polymers; phase transition; Physicochemistry of polymers; Starch and polysaccharides; Thermal analysis; thermodynamics; Konjac glucomannan; Exothermic transitions; Thermal analysis; Semidilute solution; Storage time; Thermal transition; Konjac; Order disorder transformation; Experimental study; Thermal history; Concentration effect; Oside polymer; Aqueous solution; Glucomannan
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2005.06.001

Differential scanning calorimetric experiments were designed and conducted to investigate the occurrence of two intriguing exothermic events, hitherto never reported before, on programmed heating of semi-dilute (≤1.0%, w/w) aqueous konjac glucomannan (KGM) solutions to temperatures above 70 °C. These exothermic transitions, with peak temperatures of 74–80 °C and 115–132 °C, respectively, were attributed to disorder-order transitions of different kinds. The results of storage and annealing experiments suggest that these transitions were time-dependent. The ordered structures formed on heating were heat-stable, at least up to 180 °C.