Physicochemical and structural properties of A- and B-starch isolated from normal and waxy wheat: Effects of lipids removal

摘要

Normal and waxy wheat and their A- and B-type starch granules were defatted by using soxhlet extraction method. The effects of defatting treatment on morphology, structure, and physicochemical properties on starches were investigated. The defatting result in more pores on the granule surface of normal and waxy A-type starch, while no obvious change of the B-type granules could be observed. The defatting treatment did not change the X-ray diffraction pattern of all starch granules, while the crystallinity degree of the starch samples decreased. The above structural changes on defatting decreased the light transmittance and increased swelling power of all starch samples. Meanwhile, defatting treatment changed the peak, trough, final, and setback and breakdown viscosity, gelatinization transition temperatures, and the gelatinization enthalpy of all starch samples. However, the extent of changes to starch properties on defatting was different among different samples due to differences in their amylose content and amylopectin chain mobility. Results of the present study indicate that the surface lipids on the starch granule surface have obvious effects on the physicochemical and structural properties of wheat A- and B-starch. (C) 2016 Elsevier Ltd. All rights reserved.