Effect of Fluorescent Light on Repartition of Riboflavin in Homogenized Milk

This study was designed to determine the effect of fluorescent light on riboflavin in homogenized milk and in the resulting fat, casein, and acid whey isolated therefrom. The major proportion (82%) of riboflavin in homogenized milk was associated with the acid whey fraction, about 15% with the casein phase and about 3% with the fat phase. Riboflavin loss due to light exposure (2150 lx for 48 h at 7 C) was greatest in the whey fraction. Further separation of the whey proteins by gel filtration on Sephadex G-75 superfine indicated that the riboflavin associated with the high molecular weight fraction decreased following exposure. In the whey fraction, 95% of the riboflavin was in the free form and not associated with the major whey proteins. The free riboflavin was most labile to light exposure.