Effect of ohmic heating and vacuum impregnation on the quality and microbial stability of osmotically dehydrated strawberries (cv. Camarosa)

The combined effect of osmotic dehydration/ohmic heating (OD-OH) and vacuum impregnation/ohmic heating (VI-OH) on physicochemical and quality parameters of strawberry (a(w), color, firmness and microstructure), as well as on microbial stability of storage samples at 5 and 10 degrees C, was analyzed. Treatments were carried out with a 65% (w/w) sucrose solution at 30 degrees C, and ohmic heating at 9.2.13, and 17 V/cm electric field strengths, corresponding to applied voltages of 70, 100, and 130 V. Dehydrated samples showed that water loss was greater in OD-OH treatments at 17 V/cm. The greatest solute gain, least firmness loss and least color loss were obtained in the VI-OH treatment at 13 V/cm. The shelf-life of strawberries treated with VI-OH at 13 V/cm and stored at 5 degrees C was extended from 12 d (control samples) to 25 d. Furthermore, the VI-OH treatment at 13 V/cm was the best processing condition for dehydrating strawberries. (C) 2011 Elsevier Ltd. All rights reserved.