Multi-Scale Structures, Functional Properties, and Applications of Starch Modified by Dry Heat Treatment

Dry heat treatment (DHT) is considered a green technology to modify starch structure and functionality since it does not generate effluents and avoids the use of chemical compounds, however, there is still no comprehensive understanding of the effects and mechanisms on the multi-scale structure and their relationship with functionality. This paper reviewed and analyzed the effects of DHT on multi-scale starch structures and functional properties, compared the performance of continuous and repeated DHT, discussed a mechanism of starch dry heating, and summarized the applications of dry-heated starches. DHT evaporates water, accelerates the movement of starch molecules, and breaks hydrogen bonds, which changes the multi-scale structure. In turn, structural modifications promoted by DHT affect the hydration properties, thermal stability, slowly digestible/resistant starch formation, and glycemic index. The multi-scale structure and functional changes after DHT are strongly affected by the starch botanical source and process conditions. This review contributes to understanding the starch DHT modification and establishes a theoretical basis for advancing DHT applications in the starch industry.