Title:
"Application of spectroscopic methods in the studies of gluten structure"

November 26, A-1-08. Speaker: dr hab. Agnieszka Nawrocka (Institute of Agrophysics Polish Academy of Science, Lublin).

Announcement

Spectroscopic methods are widely used in the studies of proteins structure. Among these methods, infrared and Raman spectroscopies are used the most often. Both methods are complimentary to each other and provide information about secondary structure (amide I and III bands), conformation of disulphide bridges (490 – 550 cm^-1), environment of two amino acids – tyrosine (I(850)/I(830)) and tryptophan (I(760)), and water populations (3000 – 4000 cm^-1). In some cases, fluorescence spectroscopy is also applied to determine changes in proteins structure by e.g. analysis of fluorescence emission spectra of aromatic amino acids – phenylalanine, tyrosine and tryptophan.

Gluten is a continuous, viscoelastic network formed within dough during the dough mixing process. Gluten is composed of two major proteins – gliadins and glutenins. Glutenin polymers are made up of high and low molecular weight subunits that are attached to each other via disulphide bonds, whereas gliadins interact with the glutenin polymers via hydrogen bonding and non-covalent hydrophobic interactions. Structure of gluten proteins directly affect quality of the bread dough as well as bread. From the technological point of view, gliadins impart viscosity to dough, whereas glutenins provide strength and elasticity for dough. Addition of some supplements e.g. dietary fibre preparations, polyphenols extracts or pomaces from oil productions to the bread changes its sensory quality and hence disturb structure of the gluten network.

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