Study of structural changes of gluten proteins during bread dough mixing by Raman spectroscopy.

The aim of the present study was to evaluate Raman spectroscopy in determining changes that occur in the structure of gluten proteins induced during bread dough mixing. Raman spectra were measured directly within the dough. Three particular phases of mixing were studied: under-mixing, optimum mixing and over-mixing. A thiol blocking reagent, Tris(2-carboxyethyl)phosphine (TCEP) was then used to reduce disulphide bonds within proteins to confirm the important role of disulphide bridges in gluten network formation. For the control dough, the most important changes occurred during the optimum mixing phase when an increase in intermolecular disulphide bonds, anti-parallel ß-sheet and α-helix structures was observed, combined with the hydrophobic burial of tryptophan and tyrosine residues. The addition of TCEP appeared to effectively reduce the formation of intermolecular disulphide bonds, anti-parallel ß-sheet and α-helix structures and lead to a more disordered secondary protein structure.

Effect of long-term storage conditions on wheat flour and bread baking properties.

This paper presents a study on the effect of storage conditions on wheat flour quality for 30 months. Such study may be of interest for research projects conducted over long periods. Wheat flours were stored in two types of packaging (permeable paper bags and watertight containers) and at two temperatures (ambient temperature and a cold storage room). Selected qualities parameters were evaluated regularly such as chemical stability, consistency, extensibility, resistance, water absorption, Solvent Retention Capacity and Gluten Index Performance. In addition, Near-Infrared Spectroscopy was used to monitor the flour's evolution and models were employed to predict certain parameters. The results showed that storage at ambient temperature led to significant modifications of flour parameters and baking performances, whereas storage at low temperature preserved the initial quality of the flour. A practical recommendation is to favour storage at low temperature in a sealed container to prevent interaction with oxygen and moisture uptake.