US EPA

8576757 

Journal Article 

Intrinsic spectrofluorometry applied to soft wheat (Triticum aestivum) flour and gluten to study lipid-protein interactions 

Genot, C; Montenay-Garestier, T; Drapron, R 

1984 

1 

LWT - Food Science and Technology
ISSN: 0023-6438
EISSN: 1096-1127 

17 

3 

129-133 

English 

Comparison of absorption and intrinsic fluorescence of aromatic residues of proteins from soluble fractions of soft wheat flour and gluten provided information on the interactions of lipids and proteins in these complex systems. Two different types of fractions have been studied and compared. Those mainly containing proteins were obtained by solubilization in 0.05 N acetic acid. Others mainly containing lipids were prepared by solubilization in n-hexane. Few differences in emission of acetic acid-soluble fraction compared with these of control flour appeared when the flour was defatted by n-hexane whereas large modifications of emission were observed after gluten was prepared with defatted or non defatted flour. This demonstrates modifications in aromatic amino acid residues environment and protein-protein and lipid-protein interactions during gluten formation and the role of free flour lipids in gluten structure. Lipid containing fractions still contained a small amount of proteins presumed to be mainly purothionin and exhibited a weak emission as compared with that emitted by acetic acid-soluble proteins. Their fluorescence characteristics suggested the presence of a few tryptophan residues belonging to contaminant proteins probably located at protein surface and buried in the hydrophobic environment. Furthermore, a compound absorbing near 320 nm was found in both extracts but mainly in the lipidic fractions. Excitation and emission spectra were recorded but this compound is still unidentified. © 1984.