Identification of Key Volatiles Differentiating Aromatic Rice Cultivars Using an Untargeted Metabolomics Approach.

Yu Jie,Qiaojuan Yan,Zhongjei Zhang,Tianyu Shi

doi:10.3390/metabo11080528

Abstract

Non-aromatic rice is often sold at the price of aromatic rice to increase profits, seriously impairing consumer experience and brand credibility. The assessment of rice varieties origins in terms of their aroma traits is of great interest to protect consumers from fraud. To address this issue, the study identified differentially abundant metabolites between non-aromatic rice varieties and each of the three most popular aromatic rice varieties in the market using an untargeted metabolomics approach. The 656 metabolites of five rice grain varieties were determined by headspace solid-phase extraction gas chromatography-mass spectrometry, and the multivariate analyses were used to identify differences in metabolites among rice varieties. The metabolites most differentially abundant between Daohuaxiang 2 and non-aromatic rice included 2-acetyl-1-pyrroline and acetoin; the metabolites most differentially abundant between Meixiangzhan 2 and non-aromatic rice included acetoin and 2-methyloctylbenzene,; and the metabolites most differentially abundant between Yexiangyoulisi and non-aromatic rice included bicyclo[4.4.0]dec,1-ene-2-isopropyl-5-methyl-9-methylene and 2-methylfuran. Overall, acetoin was the metabolite that was most differentially abundant between the aromatic and non-aromatic rice. This study provides direct evidence of the outstanding advantages of aromatic rice and acts a reference for future rice authentication processes in the marketplace.

Highlights

China, which is the largest producer and consumer of rice worldwide, covers a vast area that includes widely different geographical and climatic conditions
Three well-known aromatic rice varieties from different rice-producing areas in China were chosen as research objects
The volatile organic compounds (VOCs) metabolites of five rice grain varieties were identified and analyzed by HS-SPME-gas chromatography-mass spectrometry (GC-MS) based on an untargeted metabolomics approach, and Principal components analysis (PCA) analysis and a partial least squares discriminant analysis (PLS-DA) model were used to clearly distinguish the aromatic and non-aromatic rice cultivars

Summary

Introduction

China, which is the largest producer and consumer of rice worldwide, covers a vast area that includes widely different geographical and climatic conditions. These environmental differences have given rise to a rich variety of rice germplasms, including many rice varieties [1]. Aromatic rice (Oryza sativa L.) is a special rice species that can give off fragrance from their whole grain. It still has aroma after cooking and is rich in amino acids, proteins and other nutrients, so it is highly favored by consumers around the world [3]. The most famous varieties of aromatic rice in China are produced in the Guangdong, Guangxi, Zhejiang, Liaoning, and Heilongjiang provinces [5]

Objectives

Methods

Results

Conclusion