Preparation and functional characteristics of starch-lipid complexes with different oleic acid-rich glycerolipids

Starch–lipid complexes with functional properties have gained extensive attention; however, little attention has been paid to how oleic acid-based lipid types and thermomechanical treatment affect the functional characteristics of starch. This study investigated the effects of five oleic acid-based lipids (oleic acid, monoolein, diolein, triolein, and rapeseed oil) and thermomechanical treatment on the structural and physicochemical properties of wheat starch. The crystal patterns and complexing indices showed that thermomechanical treatment promoted the formation of oleic acid, monoolein, and diolein V -type starch–lipid complexes with an intact granular structure, whereas triolein and rapeseed oil formed complexes with starch. Moreover, oleic acid, monoolein, and diolein significantly altered starch gelatinisation, retrogradation behaviour, more resistant starch formed in their complexes and thus decreased its digestibility. Rheological analyses indicated that the formation of lipid complexes increased the viscoelastic modulus of starch. Our results deepen understanding of the key role of oleic acid-rich lipids in starch-based foods.