Effect of the gelatinization level of normal maize starch under extrusion on ferulic acid–starch complex formation

The interactions between starch and ferulic acid can impact the properties of starchy foods. They form an inclusion complex in the shape of amylose helices, facilitated by the hydrophobic effect. The formation of this complex depends on the process conditions during food-production. Two extrusion conditions at different temperatures (50 and 70 °C) were used to evaluate the formation of a starch-ferulic acid complex. The thermal properties of the complex were analyzed using differential scanning calorimetry, revealing that disorganizing the complex required more energy compared to control starch without ferulic acid. The high gelatinization level allowed the incorporation of ferulic acid into the amylose helix due to leached amylose during extrusion. X-ray and in vitro starch digestibility results demonstrated substantial changes, particularly in starch-ferulic acid under the conditions of high gelatinization level. These findings suggest the formation of type V inclusion complexes involving amylose-ferulic acid and their impact on digestibility properties based on the starch gelatinization level.