Abstract
Riboflavin is known to be readily destroyed by sunlight, but only recently attention has been called to the photolysis of riboflavin in milk. In order to examine effective wave length for the photolysis, liquid milk in petri-dishes covered with various light filters was exposed to white fluorescent light for 180 min and riboflavin before and after the irradiation-was fluorimetrically assayed. Riboflavin in the milk in control petri-dishes (without any filters) was lost by ca. 60 percent after the irradiation. When. blue (400-560nm), brown (mainly above 500nm) and red (above 550nm) filters were used, riboflavin losses in the same period of irradiation were about 20, 30 and 10 percent, respectively. A slight decrease in riboflavin content occurred in petri-dishes placed in the dark for 180 min. These results indicate that red-colored bottle will be the most recommendable container for protecting liquid milk from photolysis of its riboflavin.
