Amylose complexation with diacylglycerols involves multiple intermolecular interaction mechanisms

Molecular complexation mediated by amylose can delay the oxidation of diacylglycerol (DAG) but the mechanism remains unclear, and little attention has been paid to starch–DAG complexes (SDCs). Herein, SDCs with different chain lengths (12−18 carbons) were prepared via co-precipitation and the underlying complexation mechanism was comprehensively explored. The results revealed nano-scale (∼150−500 nm) features and fewer weakly bound DAGs of SDCs with increasing chain length, attributed to complicated interchain and/or intrachain crosslinking with complexing indices ranging from 73% to 91%. X-ray diffraction, differential scanning calorimetry and thermogravimetry analysis unveiled the involvement of tight and weak intermolecular interaction mechanisms between starch and DAGs, and the former exhibited higher short-range structure order, confirmed by Fourier transform infrared spectroscopy and Raman spectroscopy. Molecular dynamics simulation showed that amylose tended to form V6-type helices around dimyristoyl- and distearoyl-glycerol with average helical cavity sizes of 9.4 and 11.3 Å, respectively, predominantly driven by hydrophobic interactions. SDCs significantly enhanced the oxidative stability of DAGs and delayed the in vitro starch digestion rate. The findings provide a paradigm for the intensive processing of DAGs to improve their oxidative stability and health-promoting efficacy.