DENATURATION OF LACTATE-DEHYDROGENASE DURING SPRAY-DRYING OF BOVINE PLASMA

Denaturation kinetics of lactate dehydrogenase (LDH) during spray-dryi ng and heating of bovine plasma showed the free energy of denaturation was constant about 100 kJ/mol. Protein denaturation was investigated by polyacrylamide gel electrophoresis and solubility. At low outlet dr ying temperatures LDH denaturation was low and powders were completely soluble. At high outlet temperatures LDH denaturation was high and as sociated with powder insolubility. Electrophoretic patterns of dried s amples showed differences from raw plasma at high outlet temperatures, perhaps due to production of soluble aggregates. However, LDH was not a general index of heat denaturation in spray-drying.