Evaluation of preliminary causes for vitamin D series degradation via DSC and HPLC analyses

Scientific evidence suggests that 25-(OH) vitamin D serum levels should be above 75 nmol L−1, which is the level required for the beneficial effects of vitamin D on long-latency diseases. Supplementing vitamin D in a daily diet is advantageous for the health of elderly individuals. The focus of this study was on the causes of vitamin D2 and D3 degradation, such as vitamin D2 being left in the open for days. The differences in the analysis results for fresh vitamin D and vitamin D stored in air for several days were compared. Comparisons were also made of the differences in vitamins D2 and D3 and their origins, i.e., oxidation, thermal decomposition, and photolysis, using high-performance liquid chromatography analyses and differential scanning calorimetry tests. We also developed a novel approach to examine the effect of heat on vitamin D, including the heat reactivity properties of vitamins D2 and D3, such as the kinetics of endothermic and exothermic reactions, the natural logarithm of the pre-exponential factor (lnk 0), reaction order (n), activation energy (E a), enthalpy of melting (∆H), heat of decomposition (∆H d), isothermal conditions for the time to maximum rate, total energy release, and time until 10% conversion limited. Overall, the parameters, the reactivity properties, and the degradation results can be applied to determine the optimal conditions for vitamins D2 and D3 during cooking, storage, heat treatment, and food processing that will be beneficial to human health.