Impact of redox potential electrochemical modification and storage conditions on the oxidation reaction prevention in dairy emulsion

Oxidation reactions in milk conclude to negative consequences such as lipid oxidation, undesirable flavors, degradation of vitamins, and changes in microbial flora of milk. The objective of the study was to investigate the effect of electroreduction and storage conditions on an oil/water emulsion made of canola oil and reconstituted skim milk. The electroreduction treatments were carried out at two different anode/cathode voltage differences (0 and 4 V) on a 2% stable oil/water emulsion made of canola oil and skim milk. After each electroreduction treatment, samples of electroreduced emulsion were placed in conditions of storage in regards to headspace (0%, 10%, and 50%), temperature (4°C and 22°C) and in the dark for 14 days. The results showed that the electroreduction treatment significantly reduced the redox potential of the emulsion samples to negative values (from +85 to -412 mV) and was also able to decrease their dissolved oxygen (DO) concentration (from 3.8 to 2.5 mg.L -1). The storage conditions of headspace and temperature have had an important impact on the oxidation-reduction potential (ORP) value and the DO value. This study is the first to our knowledge to show that in storage conditions where the gaseous exchanges and especially the oxygen are limited, it is possible to maintain during 14 days a negative ORP in electroreduced oil-water emulsion. © INRA and Springer Science+Business Media B.V. 2011.