Riboflavin vitamin storage

There is no evidence of any significant storage of riboflavin in addition to the limited absorption, any surplus intake is excreted rapidly thus, once metabolic requirements have been met, urinary excretion of riboflavin and its metabolites reflects intake until intestinal absorption is saturated. In depleted animals, the maximum growth response is achieved with intakes that give about 75% saturation of tissues, and the intake to achieve tissue saturation is that at which there is quantitative urinary excretion of the vitamin. 

Multivitamin preparations containing thiamine, riboflavin, pyridoxine, calcium pantothenate, nicotinamide, folic acid, and vitamin B12 also showed no loss in activity after irradiation and four years storage at 25°C. Such substances as aspirin for intravenous injection have been sterilized and also intravenous drip solutions, where less change in lactate and citrate solutions were produced than by autoclaving. 

Leaching is also the cause for riboflavin loss from tofu. Using HPLC analysis, a 20% loss of vitamin from tofu was found after 3 to 7 days of storage at 4°C (62). The quantitative assessment of flavins in cow milk and the effect of pasteurization on these compounds were studied by Roughead and McCormick (26) using the phenol extraction technique and reversed-phase HPLC (Table 4 Fig. 7). Riboflavin (61%), FAD (26%), and 10-(2 -hydroxyethyl)flavin (11%) were the predominant flavin compounds in all milk samples smdied. The distribution of flavins in raw and pasteurized milk reveals little difference, with the exception of a decrease in the FAD content with pasteurization. 

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