Structure, physicochemical properties and in vitro digestibility of starch in corn flour with different milling processes

The effects of dry milling (DM), semi-dry milling (SDM), wet milling (WM), nixtamalization wet milling (NWM) and ultrasonic-assisted nixtamalization wet milling (UNWM) on the structure, physicochemical properties and in vitro digestibility of starch in corn flour were investigated. NWM and UNWM samples had the lowest damaged starch content and average particle size, as well as the highest thermal stability, short-range ordered structure and relative crystallinity, which exhibited excellent pasting, rheology and gel texture properties. NWM and UNWM samples showed a lower rapidly digestible starch (RDS) and a higher slowly digestible starch (SDS) and resistant starch (RS), conferring higher dietary fiber activity on corn starch. In addition, UNWM had higher milling efficiency than NWM, which facilitated industrial processing. Therefore, ultrasonic-assisted nixtamalization could enhance the quality of corn flour by improving structure, physicochemical properties and anti-digestibility of corn starch, and also achieved efficient production of corn flour.