Improved extrusion cooking technique (IECT) induces the formation of starch-lauric acid complexes: Evaluations of structure and properties

• IECT enhances production efficiency and reduces water use. • Lauric acid addition significantly impacts resistant starch of the complexes. • IECT enables LA molecules to more easily enter starch granules. Corn starch-lauric acid complex (CS-LA), classified as a resistant starch (RS), has been associated with potential physiological benefits. However, its conventional production methods remain inefficient and highly water-intensive. To address these limitations, this study investigated a novel strategy based on the improved extrusion cooking technique (IECT). The structure, physicochemical properties and digestibility of CS-LA prepared using IECT, conventional method and composite technique at various lauric acid concentrations were systematically compared. The results showed that CS-LA prepared by all three methods exhibited a typical V-type crystal structure and contained a significant proportion of resistant starch (RS). Notably, CS-LA produced via IECT demonstrated higher complex index (91.7 ± 0.1%) and RS content (30.99 ± 1.06%), along with lower viscosity compared to the other methods. As lauric acid (LA) concentration increased, the rapidly digestible starch (RDS) content decreased from 44.03 ± 0.84% to 32.23 ± 0.23%, while RS and slowly digestible starch contents increased significantly. The changes in CS-LA properties were closely associated with the extent of starch structure disruption, and the digestion followed a combination of parallel and sequential digestion patterns. Artificial neural network analysis further revealed that LA concentration had a pronounced influence on both RS and RDS contents of the CS-LA. These findings suggested that IECT processing promoted the incorporation of LA molecules into the starch granules, facilitating the formation of a more stable CS-LA after retrogradation. This work provides both a theoretical foundation and practical guidance for the industrial-scale production of CS-LA aimed at modulating starch digestibility.