Riboflavin Photochemical Degradation in Pasta Measured by High Performance Liquid Chromatography

A technique utilizing high performance liquid chromatography (HPLC) was developed to determine the kinetics of riboflavin losses in enriched macaroni as a function of temperature, water activity and light. Riboflavin and lumichrome were extracted from macaroni and assayed by reverse-phase HPLC with fluorescence detection. Riboflavin degradation and lumichrome production in macaroni occurred in two phases, a rapid initial phase followed by a slower phase. Photodegradation of riboflavin appears to follow first-order reaction kinetics. Under the experimental conditions used, more than 50% of the riboflavin content of macaroni was lost within one day. Light intensity was the rate determining factor for riboflavin loss and lumichrome production. The riboflavin level decreased with increased temperature in the second phase of breakdown.