Structure and Digestibility of Spray-Dried Corn Starch: Influence of Post-Treatments

Resistant starch (RS) has being attracted attention due to its health benefits. In this study, combination of spray drying and post-treatments is adopted to prepare post-treated spray-dried corn starch (PSDCS) with high content of RS. Effect of post-treatment conditions on structural and digestive properties of the PSDCS is investigated. Relative humidity can alter the ordered structures of the PSDCSs due to changes in equilibrium moisture content. When fixing relative humidity at 33%, improvements in short-range structure and long-range crystalline structure of the PSDCS obtained at alternant temperature of 4/30 °C (12 h/12 h) are better than those of the PSDCSs obtained at other temperatures. The highest content of RS (29.97%) is found in the PSDCS obtained at 4/30 °C, which is approximately 3.3 times of native corn starch and 5.6 times of spray-dried corn starch. These findings demonstrate feasibility of preparation of starch products with lower digestibility using spray drying combined with post-treatments and lay the groundwork for the production and application of products with high content of RS.