Characterization of volatile organic compounds in selenium-enriched brown rice tea of different colors using E-nose, HS-GC-IMS and HS-SPME-GC-MS

The volatile characteristics of brown rice tea (BRT) prepared from selenium-enriched rice varieties of diverse colors—black, red, and white—were investigated. A multifaceted analytical approach encompassing electronic nose, headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), headspace solid-phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC-MS), and electronic tongue was employed to comprehensively characterize aroma and taste profiles. It was revealed by the analysis that aldehydes, alcohols, pyrazines, and furans constituted the dominant volatile aroma compounds across all three BRT colors. Additionally, bitterness and saltiness were identified as the primary taste attributes. The levels of potentially irritating sulfides and heterocyclic volatile contaminants (including furans) were demonstrably reduced by selenium enrichment by 32 %–75 % and 8 %–55 %, respectively. The volatile flavor components identified by HS-GC-IMS and HS-SPME-GC-MS were effectively differentiated using principal component analysis (PCA) and cluster analysis. Twenty-one aroma compounds with an ROAV exceeding 1, and nine substances with an ROAV greater than 50, were pinpointed through ROAV analysis. Moreover, nineteen labeled volatile organic compounds (VOCs), including 3,5-diethyl-2-methylpyridazine, 2-pentylfuran, hexanal, and 1-butanal, were successfully screened using partial least squares discriminant analysis (PLS-DA). This comprehensive study offers insights into the flavor and taste profiles of selenium-enriched colored brown rice teas, supporting their development and optimization.