Chain length of fatty acid determines the reassembly behaviors of starch-lipid complexes following microwave heat-moisture treatment

Food postprocessing can induce the structural changes of starch-lipid complexes, however, how the chain length of fatty acids affects their reassembly behaviors during postprocessing has not been researched. Accordingly, starch-lipid complexes containing varying chain lengths of fatty acids were prepared and the changes in their structures and digestibility were investigated during microwave heat-moisture treatment. After treatment, the contents of complexed lipids, complex index, and single helix in the complexes increased, and the values were lower for complexes containing longer-chain fatty acids. Although more single helices formed for short-chain fatty acids (10 ≤ C ≤ 12), the short-range molecular order and relative crystallinity of the complexes decreased. However, the complexes containing long-chain fatty acids (14 ≤ C ≤ 18) showed the opposite changes. The relative crystallinity of treated samples increased (from 12.0 % to 20.1 %) with increasing chain length of the fatty acids. Moreover, the treated samples exhibited greater enzyme resistance.