THERMAL-DENATURATION AND DEGRADATION OF SCHIZOPHYLLAN

Size exclusion chromatography and low-angle laser light scattering have been used for studying the evolution of schizophyllan polysaccharide during a thermal treatment (t > 100-degrees-C) in aerated solution. Thermal denaturation of the native triple helices into single chains is initiated above 135-degrees-C and is complete in 10 min at 160-degrees-C. Both conformations can coexist in the 130-140-degrees-C temperature range. In the presence of oxygen, both forms of the biopolymer undergo severe thermal degradation. The rate of degradation was found to be independent of chain length and conformation. An activation energy of 104 kJ mol-1 was determined. The reaction was base-catalyzed. Analysis of chromatographic patterns indicate that the degradation probably occurs through an 'all-or-none' process.