Bioactive component behavior of cryoconcentrated beet juice after enrichment of osmodehydrated apple slices assisted...

Beet is a vegetable that has an important content of sugars, antioxidants and minerals, which are essential components for the vitality of the human body. Cryoconcentrated beet juice is an interesting osmotic agent for enriching plant tissue. The main aim of this research was to study the impregnation and retention of the bioactive compounds of cryoconcentrated beet juice in apple slices using osmotic dehydration (OD) with and without pulse vacuum (PV) application and ohmic heating (OH). Apple slices (4 × 3 × 0.5 cm) were impregnated with cryoconcentrated beet juice (50°Brix) at 30, 40 or 50 °C for 180 min with a 5 min pulsed vacuum application at the beginning of the process and an electric field of 1.33 V/cm. The water content, soluble solids, phenolic content, antioxidant capacity, betacyanins, betaxanthins and betalains content were analyzed. Samples treated with OD/OH and PVOD/OH at 50 °C for 120 min achieved the greatest loss of water and the greatest impregnation of bioactive compounds from the cryoconcentrated beet juice. The OD/OH and PVOD/OH treatments helped to retain the bioactive components and increase antioxidant capacity at all temperatures. PVOD/OH at 50 °C yielded apple slices with the highest total phenolic content during processing, and the highest concentration of betacyanins and betalains was obtained in samples treated with OD/OH at 50 °C. The results show that cryoconcentration, PV application and OH technologies are the excellent alternatives for the impregnation and retention of natural bioactive components for obtaining fortified foods.