Effects of fluorescent light on nutrition components of food

―Riboflavin contents of milk and cheese―

Abstract

For the purpose of considering the loss of the nutritional ingredient under the influence of light, the riboflavin content was analyzed in commercial milk and cheese.The riboflavin contents of the commercial milk being added to a paper container and a glass bottle were measured. The amount of riboflavin contents of the milk in the glass bottle was no less than a 23 to 56% loss as compared to that in the paper container. The illumination that was exposed to milk from a fluorescent light at the store was from 1000 to a maximum of 4210 lx.Subsequently, the rates of riboflavin loss from the milk and cheese were measured during irradiation by a fluorescent light of various illuminations and irradiation times. The rates of riboflavin loss were so high when the illumination was high and irradiation time was long, which were 25.6% by 4000 lx, and 13.8% by 2000 lx for only a 2-hour irradiation. When the illumination in a typical home was assumed, the rates of loss were 7% for a 2-hour irradiation, 35% for 10 hours by 1000 lx, and 3% for 2 hours, 15% for 10 hours by 300 lx.The riboflavin contents of cheese were more easily af fected by light compared to the milk. It rapidly decreased to 53% by the short irradiation time of 40 minutes by 4200 lx, and the loss rate was 65% in 100 minutes. On the other hand, by 1000 lx, it rapidly decreased to 50% after a 2-hour irradiation, and the loss rate was 65% in 7 hours.The illumination from a fluorescent light at the store of natural cheese was from 1000 lx to a maximum of 5500 lx. When the irradiated riboflavin contents of the outside and inside of the cheese were measured, the outside riboflavin rate of loss was 27.5 to 57.8% as compared to the inside.