Vitamin c degradation of rose hips during drying and effects of drying medium on vitamin C degradation

In this study, vitamin C degradation during drying of rose hips was investigated. The degradation of vitamin C was affected by time, temperature and content of moisture. Rate of vitamin C degradation during the drying of whole rose hips was satisfactorily described by a first-order kinetics, and the temperature dependency of the model was described by the Arrhenius relationship. The activation energy and the reaction rate constant were determined as a function of the moisture content. Drying experiments were also conducted on rose hips cut in pieces, and using air-CO2 mixtures. Cutting the rose hips before drying accelerated the drying process and increased the retention of vitamin C. The loss of vitamin C depended on the level of oxygen in the air-CO2 mixture used as a drying medium.