Ordered structure of starch inclusion complex with C10 aroma molecules

Abstract

The ordered structure of inclusion complexes (ICs) between high amylose starch and nine C10 aroma molecules were investigated using experimental approaches (diffractive, spectroscopic and thermal techniques) and theoretical molecular dynamics (MD) simulation. The starch-linear alkyl aroma ICs had a V6I crystalline structure and possessed a higher proportion of single-helix, as well as larger enthalpy changes. Starch-cycloalkyl aroma ICs showed a V7 crystalline structure, with greater crystallinity and a higher dissociation temperature. Starch-lactone aroma ICs were a mix of V6I and V7 crystalline structures whose inhomogeneous polymorphism caused a less-crystalline structure and lower thermal stability. The starch-naphthol IC showed a V8 crystalline structure, with lower transition temperatures. The MD simulation also confirmed the conformational changes of ICs. Intramolecular hydrogen bonds appeared to be the main interactions maintaining the helical structure of amylose, and hydrophobic interactions may be the main factor stabilizing the inclusion of aroma molecules in the hydrophobic inner channel.