Chemical and physicochemical properties of semi-dried organic strawberries enriched with bilberry juice-based solution

Vacuum impregnation combined with other techniques such as air drying allows obtaining not only a low-moisture product but also to enrich it with beneficial bioactive compounds. The aim of this work was to evaluate the efficacy of combined process that involves vacuum impregnation and air drying to obtain an enriched strawberry snack. The strawberry samples were vacuum impregnated with bilberry juice-based solution at three different sucrose concentrations: 10, 30 and 50 °Brix. Afterwards, the samples were subjected to air-drying treatment at 40 °C for 24 h and the obtained final products were analysed for texture, colour, total polyphenol content (TPC), antioxidant activity and sensory analysis. Moreover, the volumetric impregnation level was evaluated, and the drying kinetics were studied. The impregnated and dried samples showed higher values of TPC and antioxidant activity than those of control ones, due to the high antioxidant power of the bioactive compounds present in bilberry juice. The sample that showed the highest value of total polyphenol content and antioxidant activity was the one impregnated with bilberry juice at 30 °Brix. The impregnated and dried samples presented lower firmness and crispness in comparison to the control; however, all analysed samples were above the acceptability threshold by sensory analysis.