Analysis of secondary metabolites induced by yellowing process for understanding rice yellowing mechanism

The current study applied wide-targeted metabolomics based approach using LC-ESI-MS/MS to characterize the secondary metabolic difference between yellowed and normal rice. The results indicated that the biosynthesis of secondary metabolites including flavonoids, flavonols and phenolic acids was significantly enhanced during the rice yellowing process, which appears to be highly managed by phenylpropanoid metabolism and flavonoid biosynthetic pathways. Furthermore, rice yellowing led to an increased color parameter b* value, and a number of increased secondary metabolites in the yellowed rice such as homoeriodictyol, naringenin chalcone, 4,2′,4′,6′-tetrahydroxychalcone contributed to the yellow color. These may have application as potential biomarkers for characterizing rice yellowing.