EmulsiﬁersfromNaturalResources: TheRoleof LecithininEmulsionFormationfromMolecular Dynamics Dinais Alvarez1, Deisy Giraldo2, Cristian Blanco2, Marianny Combariza2 and Aldo Combariza1 1Grupo Investigación Modelamiento Molecular y Simulación Computacional in silico, Departamento Biología y Química, Universidad de Sucre; 2Grupo Investigación Fisicoquímica Teórica y Experimental GIFTEX, Escuela de Química, Universidad Industrial de Santander, Colombia Motivation Molecular Dynamics simulations can be applied to the study of physico-chemical parameters as interfacial tension of emulsions, e. g., a water-in-oil interface.[1] • Amphiphilic compounds as lecithins, are used as emulsi- ﬁers • Lecithins are a mix of Phospholipids (PLs), Triacylglicery- des (TAGs), and others compounds a. Phosphatidylcholine (POPC) as the commonness in lecithins., b. Di-oleoyl-linoleoyl-glycerol OOL as TAG. Computational Approximation From ensembles (Eqn. 1) < V >= ZZ V (pN, rN)ρ(pN, rN)dpNdrN (1) Using forceﬁelds: Charmm 36 FF to model intramolecular inter- actions (Eqn. 5). V ( ˆR) = X bonds Kb(b −b0)2 + X angles Kθ(θ −θ0)2 (2) + X dihedrals X j Kϕj(1 + cos(njϕ −δj)) (3) + X non−bonded−pairs−ij εij[( Rmin,ij rij )12 −( Rmin,ij rij )6] (4) + X non−bonded−pairs−ij qiqj εDrij (5) Surface tension can be measured applying the Kirkwood-Buff ex- pression (Eqn. 6) γKB = L 2 ⟨P⊥−P∥⟩ (6) All minimization and production runs were carried up using the INKARI High Performance Computational Scientiﬁc Cluster lo- cated at the Universidad Nacional de San Agustín (UNSA), Are- quipa, Perú, which features a Silicon Graphics U-Racked Cluster with Head Node SGI 2x AMD-Opteron processors, twelve-core, 2.4 GHz, 64 GB of RAM memory DDR3 1600 MHz 4 Discs of 2TB SATA 7200 RPM, 12 Server Nodes (9x SGI), each Node server with 2 AMD Opteron twelve-core processors, 2.4GHz, 64 GB of RAM memory DDR3 1600 MHz 3 SATA 2TB Disks 7200 RPM. All simulations were set-up using the GROMACS V. 2019 Molecular Dynamics code. System Deﬁnition and Details Based on an emulsion model with 80:20 volume proportion (80 mL TAG and 20 mL water) we calculated the number of molecules. Compound %Vol Vol (mL) Molar mass (g/mol) # Moles Molecules Ratio Total TAG 80 80 885.000 8.28E-02 4.98E+22 1 100 a Water 20 20 18.0150 1.11E+00 6.67E+23 13.4 1337 Compound % Mass Mass (g) Molar mass (g/mol) # Moles Molecules Ratio Total PPL 20 20 760 2.63E-02 1.58E+22 3.18E-01 34 The Volume Guesser extension from Packmol ofﬁcial webpage was used to estimate the volume of the system considering a volume per molecule as a proportion of its molar mass. Compound Molecules Density (g / mL) Molar Mass (g / mol) System Volume (Å3) Box Sides (Å) Water 1340 0.999 18.015 40117.12 34.26 OOL 100 0.9156 885 160508.02 54.35 PPLb 34 0.917 760 44040.6 35.31 The estimated volume of each PPL, TAG and WATER interface in the Z dimension is shown. According to this proportions, Packmol software was used to construct and pack all interfaces. Phase/Compound Vol. Å3 Box of side Å Size on X Size on Y Size on Z. Water 40117.12 34.26 47 47 26 OOL 160508.02 54.35 47 47 67 PPL 44040.63 35.31 47 47 28 aDensity of TAG was obtained from experimental density value of sunﬂower oil. bDensity for PPL was obtained from experimental density of soybean oil Framework Simulations and Dynamics Cell with parameters: A, B and C = 6.04350, 5.94580, 15.97680, respectively and a cubic box with al- pha=beta=gamma=90, resulting in a box of 574,10 Å. Water phase with 1337 molecules 34 molecules of POPC with polar heads oriented towards the water OOL interface of 100 molecules interacting with the POPC tails POPC interface with 34 molecules Another water interface of 1337 molecules First step: Energy Minimization • Steepest descendent optimization for 50000 steps • Electrostatic interactions were established by the Particle Mesh Ewald PME algorithm with a cut-off of 1.2 and a Van der Waals cut-off distance of 1.2. • Periodic boundary conditions PBC were applied in all direction