Analysis of volatile organic compounds in ten types of tribute Rice based on headspace-gas chromatography-ion mobility spectrometry technology

Tribute rice, recognized for its unique quality and aroma, served as an imperial staple in ancient China. Many varieties of tribute rice are still preserved after hundreds of years. What makes them premium rice and why did they gain royal preference? What are their unique flavor characteristics? Little research has explored these aspects so far. This study highlights why tribute rice is favored by royalty and provides scientific insights into its distinct aromas. Through HS-GC-IMS analysis of ten representative tribute rice varieties, 74 volatile organic compounds were detected, including 69 characterized compounds: 21 aldehydes, 20 alcohols, 8 esters, 7 ketones, 4 heterocyclic compounds, 3 terpenoids, 2 acids, and 9 unclassified substances. Aldehydes and alcohols dominated the volatile profile, collectively accounting for over 50 % of the total relative content. These identified volatile components in ten tribute rice obtained by GC-IMS could be well distinguished by principal components. Meanwhile, orthogonal partial least squares-discriminant analysis (OPLS-DA) identified 15 key discriminatory volatiles. Notably, 2-acetyl-1-pyrroline (2-AP), known for its popcorn-like aroma, was detected across all samples-likely a trait that contributed to its selection as a royal offering. These findings advance our understanding of volatile compound variations in tribute rice across geographic origins, providing a scientific basis for origin authentication and quality enhancement.