4. Freeze-Thawing Behavior of Biopolymer Gels(Papers presented at the 32nd Annual Meeting)

Abstract

Freeze-thawing behavior of biopolymer gels, different from sols or aqueous solutions, was studied by using differential scanning calorimetry (DSC). Water compartmentalized by the networks of gelatin gels or starch gels remained unfrozen when rapidly cooled, and crystallized during subsequent warming if the size of compartment was appropriately small. Methylcellulose-water system, rapidly cooled from the sol state, showed only a broad endothermic peak due to ice melting during subsequent warming. Thawing behavior of this polymer system rapidly cooled from the gel state precedently was different, and a sharp endothermic peak was observed beside the broad one. The sharp peak may be due to water excluded from the vicinity of the polymer matrices when junction zones are formed in the gelling process.