STUDY ON KINETICS OF FLUORESCENCE FORMATION IN WHOLE MILK POWDERS DURING OXIDATION

Whole soymilk powders were storaged at 37,50,60 and 70 ℃.The fluorescence of oxidized whole soymilk powders showed an excitation maximum at 355 nm and an emission maximum at 440 nm.The fluorescent compounds were soluble in the organic phase of chloroform-methanol(2∶1,V/V),and the intensity increased in proportion to both storage time and temperature.Fluorescence kinetics showed a zero-order increase,and the rate followed Arrhenius relationship with activation energies in the range of 50-70 kJ/mol.Experimental kinetic equations were derived to predict the fluorescence intensity in whole soymilk powders due to oxidation at different times and temperatures.