Starches having A- and B-type X-ray diffraction patterns (A- and B-type starches) were modified by heating at 120 °C for 2 h (HT), vacuum drying at room temperature for 20 h (VD) and steeping at 50 °C for 20 h (ST). The properties of starches were compared using differential scanning calorimetry (DSC) and dynamic viscoelasticity behavior during heat processing (G' behavior). As observed by DSC, HT rarely changed the gelatinization properties for A-type starches, but decreased the gelatinization temperatures and enthalpies (ΔH) for B-type starches. A shift of the X-ray diffractograms from B-type to A-type patterns was not detected after HT. Similar changes in gelatinization properties were observed for B-type starches after VD. ST increased the gelatinization temperatures and also narrowed the gelatinization temperature range irrespective of crystal type. Both HT and VD decreased the peak temperature (Tp) in G' behavior and increased the peak G' value for B-type starches. ST increased Tp and also decreased the peak G' value irrespective of starch crystal type. G' values after reaching Tp — which indicate the viscoelasticity of the swollen starch granules without breakdown — showed significant increases only for B-type starches after HT.
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Sekine et al. (2000) studied this question.