1H NMR-Based Chemometrics to Gain Insights Into the Bran of Radiation-Induced Colored Wheat Mutant

Abstract

Recently, wheat has attracted attention as a functional food, rather than a simple dietary energy source. Accordingly, whole-grain intake increases with an understanding of bioactive phytochemicals in bran. The development of colored wheat has drawn more attention to the value of bran owing to its nutritional quality, as well as the antioxidant properties of the colorant. The present 1H NMR-based chemometric study evaluated the compositional improvement of radiation-induced mutants in purple wheat by focusing on the predominant metabolites with high polarity. A total of 33 metabolites, including three choline derivatives, three sugar alcohols, four sugars, 13 amino acids, eight organic acids, and two nucleosides, were identified throughout the 1H NMR spectra, and quantification data were obtained for the identified metabolites via peak shape-based quantification. Principal component and hierarchical cluster analyses were conducted for performing multivariate analyses. The colored original wheat was found to exhibit improvements compared to yellow wheat in terms of the contents of primary metabolites, thus highlighting the importance of conducting investigations of polar metabolites. The chemometrics studies further revealed mutant lines with a compositional enhancement for metabolites, including lysine, proline, acetate, and glycerol.

Combining NMR and MS to Describe Pyrrole-2-Carbaldehydes in Wheat Bran of Radiation

“…The previous investigation revealed that the non-irradiated colored wheat PWB is an improved variety in terms of higher contents of the primary metabolites compared with those of other varieties. 22 Consistent with the previous observation, the present non-targeted PCA analysis placed PWB at the edges of the negative side of PC1. Moreover, the bins numbered higher than 60 (bins 60−232, "≥ bin60" for δ H 0.50− 7.64 ppm), which were attributed to the primary metabolites identified in the previous study, were placed on the same side (Figure S1, Supporting Information).…”

“…The 40 wheat bran samples were previously evaluated by targeted 1 H NMR-based analysis focusing on 33 defined metabolites. 22 In ), while no corresponding observation was in the original purple wheat bran (PWB) (Figure 1). This finding motivated further statistical analysis; thus, a spectral binning process was conducted.…”

“…Bran samples adopted in our study have been previously described. 22 Briefly, the voucher seed specimens were deposited at the Radiation Breeding Research Center, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute. A yellow wheat YW1 and a colored cultivar (purple wheat; PW) were developed from the cross "Woori-mil (Korea RDA accession no.…”

“…1 H NMR data of 40 bran extracts were obtained in our previous study. 22 Data processing for the nontargeted 1 H NMR-based metabolomics study is detailed below with a brief description of the NMR experiments.…”

“…21 In response to the research trend, the present study deals with bran fraction of colored grains and evaluates radiation breeding wheat lines. Following on from our previous targeted metabolomics study, 22 in this study, non-targeted methodology is adopted as a strategy to explore previously untargeted metabolites.…”