Thermal and crystalline properties of slowly digestible starch prepared from the starches physically modified by β‐cyclodextrins

Abstract

Slowly digestible starch (SDS) was prepared from rice starches physically modified by β‐cyclodextrin (β‐CD), maltosyl‐β‐CD, and hydroxypropyl‐β‐CD. Its thermal stability and crystalline properties were further explored, since such properties were important for SDS during heat processing. The results showed that the maximum percentage of remaining SDS was 78.2% for the starch physically modified by β‐CD and subjected to dry heating for 15 min, and 73.7% for the starch subjected to moisture heating for 15 min. The starches physically modified by β‐CD exhibited a higher peak melting temperature, conclusion temperature, and enthalpy change of melting than the control sample. The crystalline data indicated that the higher yield of SDS in the starch physically modified by β‐CD could be attributed to a greater difference of partial V‐type crystallites. More perfect crystallites and imperfect crystallites were formed, and designated as the major components of the SDS product. These findings suggest that the starch physically modified by β‐CD had higher thermal stability because of the formation of VII‐type crystallites, and was suitable for potential application during heat processing.