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Biosensors are becoming increasingly important in the food industry for application in safety and quality control among routinely used techniques such as microbiology, chromatography, or specific enzymatic methods. Biosensors offer advantages as alternatives to conventional methods because of their inherent specificity, simplicity, and rapid response. This article presents a short review of vitamin and pseudovitamin analysis techniques using biosensor technology as applied in the food industries, with particular attention to immobilization techniques of biorecognition elements, transducers, an overview of vitamin biosensors, and some future trends.

An assay for quantification of riboflavin (Rf) in milk-based products has been developed using the principle of surface plasmon resonance with on-chip measurement. The quantification was done indirectly by measuring excess of Rf binding protein (RBP) that remains free after complexation with Rf molecules originally present in the sample solution. The chip was modified with covalently immobilized Rf in order to bind the RBP in excess. A chemical modification was performed to introduce a reactive ester group at the N-3 position of the natural Rf to bind amino groups present on the chip surface. Calibration solutions were prepared by mixing a range of Rf standard solutions with an optimized concentration of RBP. The Rf content in the milk-based products was then measured by comparison of the response against the calibration. Results obtained were very close to those from an official HPLC-fluorescence procedure. The limit of quantification was determined to 234 microg/L and the limit of detection to 70 microg/L by an injection volume of 160 microL.