Molecular chemistry of plant protein structure at a cellular level by synchrotron-based FTIR spectroscopy: Comparison of yellow (Brassica rapa) and Brown (Brassica napus) canola seed tissues

The objective of this study was to use synchrotron light sourced FTIR microspectroscopy as a novel approach to characterize protein molecular structure of plant tissue: compared yellow and brown Brassica canola seed within cellular dimensions. Differences in the molecular chemistry and the structural-chemical characteristics were identified between two type of plant tissues. The yellow canola seeds contained a relatively lower (P < 0.05) percentage of model-fitted α-helices (33 vs. 37), a higher (P < 0.05) relative percentage of model-fitted β-sheets (27 vs. 21) and a lower (P < 0.05) ratio of α-helices to β-sheets (1.3 vs. 1.9) than the brown seeds. These results may indicate that the protein value of the yellow canola seeds as food or feed was different from that of the brown canola seeds. The cluster analysis and principal component analysis did not show clear differences between the yellow and brown canola seed tissues in terms of protein amide I structures, indicating they are related to each other. Both yellow and brown canola seeds contain the same proteins but in different ratios.