Vacuum impregnation and air drying temperature effect on individual anthocyanins and antiradical capacity of blueberry juice included into an apple matrix

Blueberries are an important source of bioactive compounds that can be consumed as fresh or processed fruit. The aim of this work was to study the addition of blueberry juice into apple discs by vacuum impregnation and further stabilization of the impregnated apple by air-drying and freeze-drying in order to produce a low-humidity fruit-like natural snack. The effect of processing operations was studied in terms of functional properties. Results indicated that it was possible to add blueberry juice into the structure of fresh apple slices without a negative effect on bioactive compounds. While air-drying operation implied a significant loss of the initial anthocyanin content, the final product stabilization by freeze-drying did not cause any loss of individual anthocyanin content. Results of the different analyses showed the best final product was obtained by freeze-drying or air-drying stabilization at 40 °C.