Characterisation of lipids in wheat grain as probed by microspectrofluorometry

摘要

The baking quality and storage stability of white flour are affected by its non-starch lipids content, and by the proportions of non-polar and polar lipids classes. At present, information on the lipids composition in the various parts of the wheat grain is scarce and their redistribution in the flour millstreams after milling is not well understood. Here we have implemented a novel method based on microspectrofluorometry to investigate lipids distribution in the wheat kernel. This technique has already been a proven tool to study primary fluorescence in wheat grain. For this study Nile Red was introduced as a fluorescent stain to map lipids in different compartments of a wheat transverse section. Microspectrofluorometry allows in situ characterisation of lipids material in transverse cut of wheat grain. Fluorescence spectra were recorded and decomposed into the principal spectral components which can in turn be approximated to the real lipid materials of the wheat. Using these models, spectral fluorescence imaging was performed allowing the spatial organisation of lipids in the wheat sections to be obtained.