Thermophysical and physical properties of wheat starch modified with mixtures of dicarboxylic acids and acetanhydride
Starch is widely used in food industry as thickener, stabilizer, fat mimetic etc. However, native starch has limitations in food industry applications such as high tendency toward retrogradation, low thermal resistance and shear resistance. Therefore, starch is often modified in different ways to change and improve its performance. In this research starch was isolated from two wheat varieties and modified with mixtures of dicarboxylic acids (succinic, glutaric, adipic, azelic acid) and acetanhydride (acid:anhydrid ratio 1:30) in 4, 6 and 8 % (d.w.b.). Thermophysical, pasting properties, as well as swelling power and solubility, paste clarity and freeze-thaw stability were determined. The results showed decrease of gelatinisation temperature and retrogradation after 7 days of storage at 4 °C after all modifications. Pasting temperature decreased as well, while maximum viscosity, swelling power and solubility increased. Paste clarity of modified starches depended on both wheat variety and type of reagent mix and freeze-thaw stability decreased after all investigated modifications.