Application of vacuum pulse and moderate electric field in osmodehydration of apple using concentrated juice.

Abstract

The moderate electric field (MEF) is an emerging technology in the food industry, which consists of an alternating electrical current through food; the main purpose is heating food with the inner energy generated. This technology combined with osmotic dehydration assisted with vacuum pulse accelerates the mass transfer, due to electroporation effect in the cell membrane of vegetable tissue. The aim was to study the effect of osmotic treatment with vacuum pulsed and moderate electric field using concentrated pomegranate juice as osmotic agent obtaining dehydrate apple slices (cv. Granny Smith). The apple samples were submerged in pomegranate juice of 60 °Brix at 50°C for 300 minutes. Osmotic dehydration with vacuum pulse (PVOD) and osmotic dehydration with vacuum pulse assisted by moderate electric field (PVOD /MEF) were applied. The kinetics of mass transfer showed a balance between the water loss and solid gain, the balance was reached at 90 minutes; which is consistent with prior studies. Apple slices with PVOD/MEF had the highest gain than the ones just with PVOD, due to 50 mbar pressure applied 5 minutes prior to MEF, wich its intensity was 2.6 V/cm. Results showed there was a significant gain of sol- 55