Resistant Starch Type 5 Formation by High Amylopectin Starch–Lipid Interaction

Abstract

The formation of resistant starch type 5 (RS5), primarily associated with amylose–lipid complexes, is typically attributed to starches with high-amylose content due to their affinity for lipid interactions. Recently, studies have also investigated the potential of amylopectin-rich starches to form amylopectin–lipid complexes (ALCs), expanding RS5 sources. This study explores the capacity of waxy corn starch (WS), which is rich in amylopectin, to develop ALCs with oleic acid (10% w/w) under different thermal and mechanical conditions. Specifically, WS was treated at temperatures of 80 °C, 85 °C, and boiling, with stirring times of 0 and 45 min. Results demonstrated significant ALC formation, reaching a peak complexation index (CI) of 59% under boiling conditions with 45 min of stirring. Differential scanning calorimetry (DSC) identified a notable endothermic transition at 110 °C, indicating strong ALC interactions. FTIR spectra further evidenced starch–lipid interactions through bands at 2970 cm−1 and 2888 cm−1. X-ray diffraction (XRD) analysis confirmed the presence of orthorhombic nanocrystals in native WS, with ALC samples exhibiting a V-type diffraction pattern, supporting effective complexation. This study advances knowledge on starch–lipid interactions, suggesting ALCs as a promising RS5 form with potential food industry applications due to its structural resilience and associated health benefits.

Keywords

• amylopectin–lipid complex
• orthorhombic
• oleic acid
• waxy starch
• gelatinization