title: GC study of the effect of specific heat treatment on water sorption by wheat and soy flour.
abstract: The water sorption isotherms of wheat and soy flour were constructed at 30 degrees C using the computerized inverse gas chromatographic technique. Wheat flour showed a higher sorptive capacity than soy flour. This was attributed to the higher sorptive capacity of starch, the main constituent of wheat flour as compared to that of protein, the main constituent of soy flour. Subsequently the flour samples were heat-treated at 150 degrees C for 3, 6, 12, and 24 h in the dry state. Sorption data showed a reduced water uptake both for wheat and soy flour for all heating periods ranging between 7.1 and 21.7% for wheat flour and between 7.9 and 31.6% for soy flour. The higher reduction in water uptake of the soy flour was correlated with the stronger effect of heat treatment on proteins than that on carbohydrates. Sorption data were fitted to the (Brunauer, Emmett, Teller) isotherm model and the heat of hydration of the flours was calculated.
authors.affiliation: Department of Chemistry, University of Ioannina, Greece.
authors.forename: K A
authors.initials: KA
authors.lastname: Riganakos
authors.forename: M G
authors.initials: MG
authors.lastname: Kontominas
mesh_terms: D002849:Chromatography, Gas / Q000295:instrumentation / Q000379:methods; D003296:Cooking; D005433:Flour; D006358:Hot Temperature; D013025:Glycine max; D014908:Triticum; D014867:Water
chemical_list: D014867:Water