Changes in wheat (Triticum aestivum L.) flour pasting characteristics as a result of storage and their underlying mechanisms

White wheat flour of a high and a low protein cultivar were stored at 25 °C for 84 days to study age-related changes in flour components and pasting properties. Both cultivars showed similar increases in free fatty acid contents and slight but significant decreases in extractable thiol contents. Rapid Visco Analyser peak, minimal and final viscosities as well as breakdown and setback readings of the high protein flour increased rather gradually along the storage period, while the low protein flour showed more pronounced increases of pasting profiles during the first 21 days of storage. Flour functionality is co-determined by changes in extractable thiol contents during flour storage pointing to their oxidation and the release of free fatty acids which results in additional formation of amylose-lipid complexes and additional substrate for lipoxygenase action which can lead to more extensive co-oxidation of gluten, thereby influencing rheological properties.