Efficient production of moist heat-treated starch

A process for producing heat-moisture treated starch by treating starch in a pressure vessel resistant to both internal and external pressure and equipped with a vacuum line and pressure-steam line. The process comprises treating the starch in the pressure vessel under reduced pressure of 200 Torr or less in a first step, and then introducing steam into the pressure vessel in a second step, thereby performing heat treatment on the starch. The treating of the starch under reduced pressure tends to remove entrained air in spaces between particles of starch.