Abstract— Fresh and dried by convection and lyophilisation bilberries (Vaccinium myrtillus L.) were examined for content of water, vitamin C, vitamin E, total anthocyanins, total polyphenols and level of antioxidant activity against the DPPH radical. Both products were analyzed immediately after drying and after 4, 8 and 12 months of storage at 2 ± 1 ºC and 20 ± 2 ºC. Fresh fruit had a dry matter content of 14.74%, 100 g of which contained 208 mg vitamin C; 36.4 mg vitamin E; 2064 mg anthocyanins; and 5000 mg polyphenols, with antioxidant activity of 1750 µM Trolox eq/1 g dry matter. After 12 months’ storage, retention rates in products dried by convection and sublimation were respectively: vitamin C 38–47% and 49–53%; vitamin E 73–77% and 76–82%; anthocyanins 47–54% and 55–59%; polyphenols 68–74% and 72–74%; and antioxidant activity 63–70% and 73–77%, the lower value referring to storage at room temperature and the higher to chilled storage. There were no effect of storage temperature on rehydration of both products. Storage led to a significant increase in the proportion of red and yellow colors in both types of dried product compared to the raw material and product after drying.
Keywords— antioxidants, bilberry, convection drying, freeze-drying, storage, quality.
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