Use of redox potential modification by gas improves microbial quality, color retention, and ascorbic acid stability of pasteurized orange juice

The aim of this paper was to study the effect of both redox potential (Eh) and pasteurization of orange juice on stability of color and ascorbic acid, and growth recovery of microorganisms during storage at 15 degreesC for 7 weeks. Three conditions of Eh, +360 mV (ungassed), +240 mV (gassed with N-2) and - 180 mV (gassed with N-2-H-2) were applied to orange juice. Both thermal destruction and recovery of sublethally heat-injured cells of Lactobacillus plantartun and Saccharonlyces cerevisiae were investigated. While oxidizing conditions were the most effective for thermal destruction of L. plantarum and S. cerevisiae, reducing conditions decreased recovery of heated cells of S. cercvisiae. In addition, gassing the juice with N-2 or N-H, increased color retention and ascorbic acid stability. The present study demonstrated that juice must be reduced just after the heat treatment in order, firstly, to maximize microbial destruction during pasteurization, and secondly, to prevent the development of microorganisms and stabilize color and ascorbic acid during storage. (C) 2003 Elsevier Science B.V. All rights reserved.