Molecular dynamics of vegetable oil extraction and degumming: Analysis of micelles and phospholipid bilayers in different solvents

Understanding the molecular-level mechanisms of vegetable oil extraction and degumming remains limited. This study aimed to investigate these processes using molecular dynamics (MD), with a focus on the challenges associated with replacing n-hexane with ethanol. MD simulations with a coarse-grained force field (Martini 3) were conducted to examine the behavior of phospholipid mono/bilayers with and without triacylglycerol in various solvents, including water, absolute and aqueous ethanol (with 0%-10% water content by weight), and n-hexane. Trilinolein and phospholipids with 16-18 carbon tails and 0-2 unsaturations were considered. The degree of unsaturation and tail size of phospholipids did not significantly affect bilayer formation in water. However, they influenced bilayer organization, as measured by the order parameter, bilayer thickness, and area. The phospholipid bilayer, composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), exhibited a well-defined structure in water, partial disruption in ethanol, and complete disruption in n-hexane. The presence of triacylglycerol had no effect on phospholipid monolayers in water but increased lipid disorder in ethanol. Minor amounts of water in ethanol did not significantly alter the behavior of the lipid layers. MD simulations, combined with artificial intelligence, identified and quantified the formation of micelles during the degumming process, both in conjunction with n-hexane extraction and independently as a function of water concentration. The volume and number of micelles were strongly influenced by the water content. Molecular dynamics in food engineering is relatively limited and scarce because of the complex nature of the systems. However, this study successfully demonstrates its applicability in this context.