Effects of oat lipid-starch complexation on starch structure, freeze-thaw stability and pasting characteristics under Ultra-high pressure treatment

Ultra-high pressure (UHP) is an emerging green non-thermal technology that can modify macromolecules like starch, altering its structure and properties. Using oat starch as the raw material and adding 0-15 % oat lipids, starch-lipid complexes were prepared by treatment at 0-500 MPa. This study investigated how UHP-induced complexation between oat lipids and starch affects the microstructure and physicochemical properties of oat starch. The results showed that at 400-500 MPa, lipids promote the formation of starch granules into network-like aggregates or large clusters, reducing relative crystallinity and short-range molecular order. The crystal structure type transitions from type A to type V, while increasing the double helix structure of starch molecules. These structural changes significantly influenced the gel texture properties of starch, enhancing its thermal stability and freeze-thaw stability. Furthermore, the formation of oat starch-lipid complexes via hydrogen bonding under UHP treatment delayed the gelatinization of oat starch and inhibited its retrogradation.