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.

摘要 乳发生氧化反应会对乳的质量会产生负面影响,如脂质氧化、不愉快风味物质的产生、维生素损失以及微生物菌群的改变。本文研究了电解还原和贮藏条件对以菜籽油/还原脱脂奶形成的水包油 (O/W) 型乳浊液的影响。电解还原反应是在以2%菜籽油/脱脂粉形成的水包油型乳浊液中通过不同阳极/阴极电压差 (0伏和4伏)来完成的。电解还原处理完后的乳浊液样品放在含有不同顶部空气体积 (0,10和50%) 的包装容器中,在一定的温度(4和20 °C) 和避光条件下保藏14天。实验结果表明:电解还原处理能够将乳浊液的氧化还原电位显著地降低到负值(从+85降低到-412 mV),同时还能降低样品中溶解氧的浓度(从3.8降低到2.5 mg.mL⁻¹)。包装顶部的体积和贮藏的温度能够显著降低氧化还原电位 (ORP) 值和溶解氧 (DO)。本研究证明了在此贮藏条件下气体交换特别是氧气交换被限制,在14天内贮藏过程中有可能使电解还原的水包油型乳浊液维持在负氧化还原电位的情况下。