The influence of different drying methods on the molecular structure and digestive resistance of type 3 resistant starch (RS3)

The extent to which the starch chains and water molecules in resistant starch (RS) are affected by different drying methods is not well defined. This research aims to reveal the effects of water distribution on molecular structure and digestibility of RS with hot air drying, spray drying and vacuum freeze drying. The findings indicated the amylose content (19.53 %), moisture content (7.52 %), proportion of bound water (82.0 %), crystallinity (22.50 %) and RS content (17.72 %) of hot air drying were the highest. The amylose content and moisture content of spray drying were basically the same as those of vacuum freeze drying. Spray drying exhibited a lower proportion of bound water than vacuum freeze drying but showed greater crystallinity than vacuum freeze drying. Ultimately, a double-helix model of starch supported by water molecules was established, and a water molecule substitution method was proposed to enhance the RS.