Influence of chokeberry juice concentrate used as osmotic solution on the quality of differently dried apples during storage

Braeburn variety was subjected to the process of osmotic dehydration in sucrose solution with addition of chokeberry juice concentrate. After drying by two different methods (convective- and freeze-drying), apples were stored in three different temperatures (25, 35 and 45 °C) for a period of 12 months. The aim of the study was to determine selected physical and chemical changes after storage time in each group and to show benefits of the pre-treatment use. Mass changes, water content, water activity and total colour difference Δ E , as well as anthocyanins and polyphenols content in stored dried apples were marked. It was considered that different storage conditions were statistically significant and influenced on level of changes. Storage in medium temperature (35 °C) proved to be the best efficient in terms of the lowermost values of water activity, small mass changes, as well as the smallest colour changes. Addition of chokeberry juice concentrate resulted in a significant increase of polyphenol content in dried apples. Although they were stored for a long time at different conditions, polyphenol compounds were still substantial amounts in the apple samples.