Resistant Starch Formation from Corn Starch by Combining Acid Hydrolysis with Extrusion Cooking and Hydrothermal Storage

Acid hydrolysis process (AHPS) combined with hydrothermal storage process (HSPS) and extrusion cooking process (ECPS) are performed to obtain resistant starch (RS) from corn starch (CS). CS is subjected to AHPS citric, phosphoric acids, and HCl and thermal processes: 1) ECPS at 100 °C, 18% moisture content, and 220 rpm; 2) HSPS at 120 °C for 1 h, then storing at low temperature (4 °C) for 24 h. Evaluations in the different treatments are: RS, water absorption index (WAI) and solubility index (WSI); rheological, thermal, and microstructural properties. Treatment HAL results in the highest yield of RS (13.19 g/100 g), which increases WAI and WSI, low viscosity, gel hardness, ΔH and microstructural analysis showing agglomerated structures (30 µm) of diameter. On the other hand, HAC and HAP generated values of RS (8.47–9.19 g/100 g), respectively. Results show that pre-treatment by AHPS combined with HSPS is an alternative for obtaining RS, which exhibits suitable physical properties and is applicable to different dietary matrixes, at a 20-fold increased yield.