Metabolite profiling of foxtail millet varieties from Qingyang using GC–MS and LC–MS analysis

Foxtail millet has been cultivated in Gansu Province for centuries, with several dominant cultivars; however, the metabolic differences among these varieties remain unclear. Therefore, the volatile and non-volatile metabolites of five different millets cultivars were analyzed using GC-MS and LC-MS techniques. A total of 64 volatile compounds were detected by GC-MS, among which aldehydes were the main contributors to foxtail millet flavor. A total of 1512 metabolites were detected by LC-MS. Comparison of HMDB (Human Metabolome Database) showed that the proportion of lipids and lipid-like molecules among the metabolites of JG21, ZZ13, and JF107 was the highest, while those of HM and JG1 predominantly consisted of organic acids and their derivatives. Additionally, 16 differential metabolites of polyphenols were screened and the biosynthetic pathways of flavonoids such as apigenin, luteolin, and phloretin were identified through KEGG (Kyoto Encyclopedia of Genes and Genomes) annotation. This study can provide a reference for the processing and quality control of downstream products of foxtail millet.