Formation of debranched wheat starch-fatty acid inclusion complexes using saturated fatty acids with different chain length

Abstract

It is well known that inclusion complexes between starch and lipid can inhibit enzymatic degradation as well as retrogradation of starch. In this study, debranched wheat starch (DWS)–fatty acid (FA) complexes were prepared using four saturated FAs with different chain lengths: lauric acid (LA), myristic acid (MA), palmitic acid (PA), and stearic acid (SA). The WS was hydrolyzed by pullulanase to produce linear starch molecules. The complexed FA in WS and DWS was determined by Soxhelt extraction after acid hydrolysis. The highest FA content was obtained from the DWS-SA complex. The water holding capacities of the complexes decreased after debranching WS and complexation with FAs, because of the structural change and the increased hydrophobicity of the WS molecules. In DSC analysis, endothermic enthalpy revealed the content of helical structure. The DWS-SA complex had the highest content of helical structure and the peak for type II crystalline structure. Moreover, the V-type XRD pattern was more distinctly observed when the complexes were formed with long-chain FAs (PA and SA) compared to short-chain FAs (LA and MA). These results suggest that the capability of DWS to form a lipid complex varies depending on the FA chain length.