Storage changes in lactose and protein of lactoperoxidase - H2O2 system treated milk preserved with formalin

Effect of formalin as sample preservative was studied on lactoperoxidase - hydrogen peroxide system activated milk. Lactoperoxidase system (LP25:15 an d LP70:30) was activated by adding 25 ppm and 70 ppm thiocyanate and 15 ppm and 30 ppm hydrogen peroxide in two different experiments. These samples w ere analyzed for lactose and protein. The lactose values were found to be 5 .01+/-0.02% and 5.02+/-0.02% in LP25:15 and LP70:30 activated milk samples, respectively. The protein values in these samples were 3.70+/-0.01% and 3. 79+/-0.03%. After addition of 0.4% formalin and storage upto 6 months, no s ignificant change (P<0.01) was observed in lactose and protein values. Even after the storage of 2, 4 and 6 months, these values remained unchanged.