Abstract: In order to study the effect of low temperature plasma treatment on the flavor characteristics of raw and cooked brown rice, gas chromatography-ion mobility spectrometry (GC-IMS) was used to measure and analyze the characteristic flavor compounds of raw and cooked brown rice before and after low temperature plasma treatment. The differences in the fingerprints of volatile organic compounds in the samples were characterized by data visualization, and the plug-in Matching matrix in the LAV software was used to analyze the similarity among the samples. The results showed that the similarity of the volatile substances between low temperature plasma-treated brown rice (LTP-BR) and brown rice (BR) was 83.25%. The relative concentrations of alcohols, ketones and terpenes in raw BR such as 2,3-butanedione, acetone, eucalyptus monomer, eucalyptus dimer, n-hexanol monomer, n-hexanol dimer, diallyl disulfide, pinene and limonene increased and new compounds responsible for floral, pine-like and other refreshing odors were detected after LTP treatment. The similarity between cooked brown rice (C-BR) and cooked, low temperature plasma-treated brown rice (C-(LTP-BR)) was 89.5%, and the relative concentrations of aldehydes and terpenes in C-(LTP-BR) samples increased. Therefore, LTP treatment had a positive effect on the overall flavor of cooked brown rice, enriching the flavor without producing off-flavor substances. This study provides a theoretical basis and data support for applying low-temperature plasma to improve brown rice flavor.

Key words: low temperature plasma; brown rice; volatile flavor substances; ion mobility spectrometry