Physicochemical Properties and Digestibility of Heat Moisture-Treated Potato Starches for Different Treatment Conditions

Potato starch was subjected to heat moisture treatment (HMT) in which the temperature and moisture content were varied. Two different levels of moisture content (30 and 35%) and temperature (100 and 120 degrees C) were selected. The crystallinity of the starches decreased after HMT, as confirmed by both X-ray diffraction (XRD) and Fourier Transform Infra-Red (FT-IR) analysis, and the XRD pattern of native starch changed from B-type to A+B type after HMT. Swelling, solubility, clarity and freeze-thaw stability of the HMT starches were less than native starch and were found to be dependent on both temperature and moisture content. Pasting viscosities of the modified starches were significantly lower than native starch and were found to be more for the starches treated at 120 degrees C than the starches at 100 degrees C. The pasting temperature increased after modification. The firmness of the modified starch pastes increased whereas the consistency decreased. The formation of resistant starch increased after HMT.