Cold plasma treatment of brown rice: a review of microbial safety quality and underlying mechanisms

Abstract

Cold plasma has emerged as a promising non-thermal technology for improving the microbial safety, storage stability, cooking quality, and germination performance of brown rice. Previous studies have reported representative effects, including microbial reductions of more than 6 log and decreases in cooking time, hardness, and chewiness by 27.4%, 30.68%, and 40.23%, respectively. However, variations in discharge conditions, reactor configurations, gas composition, sample properties, and treatment endpoints have led to differences in reported outcomes. To address this issue, this review proposes a characterization-guided optimization strategy that links plasma discharge behavior, reactive-species profiles, and brown rice quality responses. Recent progress in cold plasma treatment of brown rice is summarized, with emphasis on microbial inactivation, enzyme inhibition, contaminant degradation, surface modification, water absorption, texture improvement, aroma regulation, and germination-related bioactive changes. Particular attention is given to how plasma characterization methods, including discharge morphology, electrical measurements, optical emission spectroscopy, absorption spectroscopy, and mass spectrometry, can be used to interpret treatment mechanisms and guide parameter optimization. Finally, future research should strengthen the connection between plasma measurements and rice-matrix responses to improve process reproducibility, scale-up uniformity, and safety assessment in plasma-assisted brown rice processing.