Comparison of two alternatives of combined drying to processing of blueberries (O`Neal): Evaluation of the final quality.

RODRIGUEZ, A; ZARO, M.J.; LEMOINE, ML; MASCHERONI, R

DRYING TECHNOLOGY

TAYLOR & FRANCIS INC

Año: 2015

0737-3937

In this work, we examined and compared two combined alternatives for thedrying of blueberries. Pretreatments of osmotic dehydration (60°Brix sucrose solution,at 40°C for 6h) and hot air drying (60°C, 2.5 m/s for 90 min) were performed to reach the same water content. Pretreated blueberries (O´Neal) were then dried by microwave at different power levels (562.5W, 622.5W and 750W). The combined drying processeswere also compared with hot air drying alone (control). The effects of the processes over blueberries were studied in terms of decrease in water content, drying rate, mechanical properties (firmness and stiffness), optical properties (L*, a* and hue angle (h)), antioxidant capacity and rehydration capacity. The hot air-microwave drying decreased the process time and presented a high drying rate compared with the osmotic dehydration-microwave processesandthe control drying. In terms of quality, the antioxidant and rehydration capacities were the most affected. The results showed that the best drying method to obtain the desired final product was the hot air-microwave drying (750W).