Effect of operating conditions on structure and digestibility of spray-dried corn starch

Spray drying has been widely applied in food industry due to its efficiency and low cost. Exploring feasibility to prepare resistant starch (RS) via spray drying could open up new route to produce starch-based products with low glycemic index efficiently. In this study, effects of spray drying operating conditions on the structure and digestibility of recrystallized spray-dried corn starch (RSDCS) were explored. Apparent amylose content (AAC) and swelling power (SP) of the RSDCSs increased after the spray drying and recrystallization. Particle size of the RSDCSs decreased significantly with increase of compressed air flow and decrease of starch suspension concentration. Furthermore, the short-range order, long-range order, and content of RS in the RSDCSs decreased with increase of compressed air flow and starch suspension concentration. The Pearson's correlation analysis showed that digestive properties of the RSDCSs were mainly related to the short-range ordered structure and crystalline structure. Moreover, Mantel analysis revealed that operating conditions changed the digestibility of the RSDCSs through impacting crystalline structure, AAC and SP. The highest content of RS in the RSDCSs (23.08%) was increased near 2.6 times comparing to that of native corn starch (9.02%).