TY - JOUR TI - Phosphorescent properties of riboflavin and its potential applications in food quality and food safety DO - https://doi.org/doi:10.7282/T3TF00J6 PY - 2016 AB - This project characterized the triplet properties of riboflavin and demonstrated that riboflavin, a widespread vitamin in foods, has the potential to be used as a phosphorescent sensor for food quality and as a photosensitizer for food safety. Phosphorescence spectroscopy has been used as a sensitive tool to study molecular motions in supercooled liquid and glass. Since molecular level movements play a critical role in determining macroscopic quality attributes of amorphous foods, phosphorescence measurement thus can serve as an optical analytical tool that leads to a better understanding of macroscopic quality attributes from a molecular perspective. In this study, phosphorescence from riboflavin and its sensitivity to molecular motions was first characterized in 3:1 glycerol/water mixture (v/v) over the temperature range from 77K to 200K and in amorphous sucrose matrix from 243K to 373K. The results suggested that riboflavin phosphorescence is sensitive to the secondary relaxation processes below the glass transition temperature. Riboflavin phosphorescence was then utilized to study the effects of molecular size and the addition of plasticizer in six malto-oligomers, three dextrans of different molecular weights, and four dextran films with different glycerol content. The results suggested that the molecular mobility increased with the increase in molecular size and that low added glycerol content (<10%) reduced mobility while high glycerol content (>22%) increased mobility. Phosphorescence also provides direct information on excited triplet state properties of a molecule, including its interaction with oxygen. Triplet molecules collide with oxygen and form singlet oxygen, a reactive species that is detrimental to living cells and microorganisms. Riboflavin has shown efficacy for virus inactivation for blood disinfection and has the potential to photo-inactivate pathogens as an environmental-friendly photosensitizer. To better understand the mechanism between triplet riboflavin and oxygen, in this study, oxygen quenching rate of riboflavin was characterized in three amorphous carbohydrate films: 6k Da dextran, 5% glycerol-dextran, and methylcellulose. Additionally, the singlet oxygen generation efficacy of riboflavin was studied under various irradiation wavelengths. KW - Food Science KW - Vitamin B2 KW - Food--Safety measures LA - eng ER -