DETERMINATION BY HPLC OF CHANGES IN RIBOFLAVIN LEVELS IN MILK AND NONDAIRY IMITATION MILK DURING REFRIGERATED STORAGE

Riboflavin, a water-soluble light-sensitive vitamin, was determined in milks and nondairy imitation milks, by HPLC with ultraviolet-visible detection. The riboflavin content ranged from 1.16 to 1.31 mug ml-1 in cows' milk, and from 1.33 to 1.44 mug ml-1 in nondairy imitation milks. When the opened containers were stored in a refrigerator at 8-degrees-C, in the dark, the loss of riboflavin in cows' milk samples ranged from 16.0 to 23.4%, and nondairy imitation milk samples ranged from 12.5 to 16.5% of the initial values.