HPLC analysis of dehulled red, black and non-colored indica and japonica rice subspecies revealed
significant differences in the contents of the anthocyanins cyanidin-3-glucoside and peonidin-3-
glucoside. The rice materials were subjected to a comparative capillary gas chromatography-based
metabolite profiling approach. The employed extraction and fractionation protocol enables the analysis
of a broad spectrum of lipophilic and hydrophilic low molecular weight constituents from different
chemical classes. The method covers not only primary metabolites (e.g. sugars, fatty acids) but also
nutritionally relevant constituents (e.g. a-tocopherol, g-aminobutyric acid). Statistical assessment of the
data via principal component analysis and agglomerative hierarchical clustering revealed a distinct
grouping of the different colored rice subspecies on the basis of their metabolite profiles. Compared to
non-colored and red rice, black rice exhibited, in particular, higher levels of fatty acid methyl esters, free
fatty acids, organic acids and amino acids.