Comparison of two alternatives of combined drying to processing of blueberries (O´Neal): evaluation of the final quality

A.RODRIGUEZ; M.J.ZARO; M.L. LEMOINE; R.H. MASCHERONI

DRYING TECHNOLOGY

TAYLOR & FRANCIS INC

Lugar: Londres; Año: 2016 vol. 34 p. 974 - 985

0737-3937

In this work, we examined and compared two combined alternatives for the16 drying of blueberries. Pretreatments of osmotic dehydration (60°Brix sucrose solution,17 at 40°C for 6h) and hot air drying (60°C, 2.5 m/s for 90 min) were performed to reach the18 same water content. Pretreated blueberries (O´Neal) were then dried by microwave at19 different power levels (562.5W, 622.5W and 750W). The combined drying processes20 were also compared with hot air drying alone (control). The effects of the processes21 over blueberries were studied in terms of decrease in water content, drying rate,22 mechanical properties (firmness and stiffness), optical properties (L*, a* and hue23 angle (h)), antioxidant capacity and rehydration capacity. The hot air-microwave24 drying decreased the process time and presented a high drying rate compared with the25 osmotic dehydration-microwave processesandthe control drying. In terms of quality, theantioxidant and rehydration capacities were the most affected. The results 26 showed that the27 best drying method to obtain the desired final product was the hot air-microwave28 drying (750W).