Dough mixing is a crucial stage in the production of bread, particularly in modern large scale processes that utilise high speed mixers to develop the dough. Mixing involves combining the flour, yeast, salt and other ingredients with water to form a single cohesive dough mass. As the mass is mixed, complex chemical and rheological changes occur that result in the formation of a thin gluten film that surrounds the starch granules. This film is derived from protein and lipid components in the flour and involves the interaction of proteins through disulfide bonds, association by secondary hydrogen and hydrophobic bonds, and the formation of lipid-protein complexes.1 The formation of this film enables the dough to retain gas and contributes texture and volume to the finished product. However, the precise physical and chemical mechanisms of these protein-lipid-starch interactions remain unclear. The ability to observe these changes at a microscopic level may provide more information on the exact nature and effect of these changes. A variety of techniques have been applied to the study of dough microstructure including light microscopy, electron microscopy and more recently, confocal scanning laser microscopy. Traditional microscopic techniques may not present precise information because of a need to 'freeze' or 'fix' materials with an associated risk of subsequently viewing artefacts. Laser scanning confocal microscopy (LSCM) is a non-invasive technique, which allows materials to be visualised in three dimensions in a natural dynamic state. Recently LSCM has been applied to the study of bread dough structure,3"4| 5 but at present the application of this technique to bread doughs is still evolving. The approach taken in this study was to investigate the relationship between dough components and dough development during mixing through LSCM using a dual staining that allowed the comparison of structural changes in the dough as it was mixed on a high speed mixer.
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