Application of cold plasma for rice bran preservation: Effects on stability and quality

The storage of rice bran is challenging for traditional methods, making it crucial to explore new technologies. This study used dielectric barrier discharge (DBD) plasma with air and argon as working gases to treat rice bran under various voltage and time conditions. The effects on rice bran stability and quality were evaluated by analyzing changes in color difference, acid value (AV), peroxide value (POV), fatty acids, volatile components, and antioxidant capacity. Results showed that neither air nor argon plasma significantly affected rice bran color but both enhanced its antioxidant capacity. Higher voltage and longer treatment time improved antioxidant capacity while reducing γ-oryzanol and α-tocopherol levels. Air and argon plasmas significantly affected the volatile components of rice bran; aldehyde-like substances increased with air plasma while acids increased with argon plasma treatment. The rate of increase in AV during storage decreased significantly after treatment with air or argon plasma. Plasma treatment substantially increased the POV initially but decreased over storage duration. Air plasma exhibited better preservation effects compared to argon plasma. Principal component analysis (PCA) indicated that air plasma at 55 kV for 8 min demonstrated optimal characteristics for rice bran storage. Although cold plasma has demonstrated potential in rice bran storage, the issues on oxidation of polyunsaturated fatty acid and potential loss of active ingredients should be solved in the future.