Fruits of bilberries and raspberries were sublimatically dried, and, next, stored during a period of 270 days. After drying and during storing, the colour, water content, and water activity of samples were controlled. Considerable changes in the colour of raspberries were found; they were caused by dewatering (the fruit colour was brightened up) and by storage (the fruit colour was darkened). Those changes were evidence of chemical changes in the colour compounds. The process of drying the frozen bilberries and their long-lasting storing did not cause significant changes in their colour.
freeze-drying, bilberries, raspberries, storage, colour