Complexation behavior and physicochemical properties of maize starch-linolenic acid complexes prepared using corn...

In this study, starch-linolenic acid complexes were prepared using the extrusion method with corn starches of varying amylose contents and α-linolenic acid (ALA) as raw materials. The effects of different amylose and ALA contents on the complexation state and physicochemical properties of the starch-linolenic acid complexes were investigated. The results indicated that the complex formed by normal maize starch and 9 % ALA (EMS-9%ALA) had the highest complexation index, reaching 90.03 %. X-ray diffraction results analysis revealed that both high-amylose maize starch (G70) and normal maize starch (MS) could form V-type crystalline structures with ALA among the three types of starches. Scanning electron microscopy and ¹³C solid-state nuclear magnetic resonance spectroscopy analyses demonstrated that, compared to MS and waxy maize starch (WMS), the structure of G70 could not be completely disrupted during the low-temperature extrusion process, which hindered the formation of amylose-ALA complexes. In contrast, MS was more likely to form amylose-ALA complexes and provided better protection for ALA. Furthermore, the in vitro release experiment results indicated that the EMS-9%ALA complex had certain slow-release properties and a relatively high release rate of 85.52 %. These findings suggest that extrusion more readily altered the helical structure of normal maize starch, facilitating the entry of ALA into the helical cavity. Therefore, normal maize starch is the optimal choice for preparing such complexes by the extrusion method.