Effect of hydrothermal treatment and drying temperature on the pasting properties of whole grain cereal flours

Sammanfattning

Whole cereal grains are increasingly promoted as sustainable and healthy food ingredients, and hydrothermal treatment can be used to improve mineral bioavailability through phytate degradation. Such treatment may however also influence starch functionality. The aim of the study was to investigate how hydrothermal treatment and different drying temperatures affect the rheological properties of whole grain wheat, rye, and barley flour. Rheological measurements, microscopy, and particle size distribution analyses were performed on untreated and hydrothermally treated cereal samples dried at different temperatures, which were supplied by the company Good Grains. The barley samples generally exhibited rheological behaviour most consistent with starch annealing, including increased pasting onset together with reduced peak, final and breakdown viscosity, while the wheat and rye samples instead showed more mixed responses. Differences in particle size distribution and possible partial pre-gelatinization may also have contributed to the observed rheological behaviour. Overall, the results suggest that hydrothermal treatment may influence starch functionality in whole grain cereal flours in ways partly consistent with starch annealing, particularly in barley, which may have potential applications in food products where improved thermal and shear stability are desirable.