Iodine absorption properties and its effect on the crystallinity of developing wheat starch granules

Wheat starches at different stages of maturities were evaluated for their iodine absorption properties by measuring the ratio of absorption to reflection spectra (K/S) and crystalline structure by using wide angle X-ray scattering (WAXS). The surface of starch granules was also visualized by using atomic force microscopy (AFM). The K/S spectral data demonstrated different levels of mobility of starch polymers at different stages of maturity and the mobility of longer chain polymers with increasing moisture contents. Iodine did not change the characteristic A-type crystalline pattern. However, the extent of effect of iodine on starch crystallinity was affected by maturity and moisture content of starches. AFM images of iodine exposed starches supported the interaction of iodine molecules with starch polymers. Differences in surface features were observed for different maturities.