Structural characteristics and glucose response in mice of potato starch modified by hydrothermal treatments

The structural properties and digestibility of slowly digestible hydrothermally treated potato starch (SDS) were investigated. The potato starch with 20, 30 or 40% moisture content was heated at 100 °C for 30 min, and then kept at 30 °C or 70 °C for 12 h. The sample with 30% moisture content, heated and kept at 30 °C, produced the highest SDS content (37.5%). The modified products were analysed with scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry (DSC). The cross-section showed a large hollow area and X-ray patterns were altered from B- to a mixture of B- and A-type. DSC of the heated samples demonstrated a broader gelatinisation temperature range compared with the heated-and-stored samples. In vivo glucose responses with mice correlated with the in vitro starch digestibility experiments. This study showed that structural changes during hydrothermal treatment of potato starch significantly affected digestibility and blood glucose levels in mice.