Combination Mechanism and Structural Properties of Complexes between Lipid and Small Granule Starch Isolated from Agriophyllum squarrosum (L.) Moq. Seeds

This study investigates the combination mechanism and structural properties of Agriophyllum squarrosum (A. squarrosum) starch (AS)-lipid complexes during pasting in the rapid viscosity analyzer compared with maize starch (MS)-lipid complexes. AS-dodecanoic acid (DA) and MS-DA samples with lipid contents of 0-125 mg, and starch-DA samples with different RVA pasting times (8-13 min) are prepared and characterized. Complexing index (CI) analyses show the peak of CI values occurred at 2.5 g starch with 62.5 mg DA for both mixtures, and there are two peaks of the complexes amount for AS-DA systems compared with one of which for MS-DA systems. The hardness of starch-lipid gels decreases significantly (p < 0.05) as the lipid content increases from 0 to 75 mg or as time went on in one RVA protocol. Enthalpy change, structural order, and resistant starch content during the gelation of the mixtures indicated starch-lipid complexes are mainly formed during the setback stage for two starches, and AS-DA complexes underwent a process of combination-disruption-recombination-disruption with ongoing cooling. These results reveal the formation process and structural properties of AS-DA complexes during the retrogradation process and provided a better understanding of rational utilization of A. squarrosum starch.