Multi-Scale Modelling And Coarse-Grained Analysis Of Triglycerides Dynamics

Polymorphic phase transitions in triglycerides and their mixtures studied by SAXS/WAXS techniques: In bulk and in emulsions

Triacylglycerols (TAGs) exhibit a monotropic polymorphism, forming three main polymorphic forms upon crystallization: α, β' and β. The distinct physicochemical properties of these polymorphs, such as melting temperature, subcell lattice structure, mass density, etc., significantly impact the appearance, texture, and long-term stability of a wide range products in the food and cosmetics industries. Additionally, TAGs are also of special interest in the field of controlled drug delivery and sustained release in pharmaceuticals, being a key material in the preparation of solid lipid nanoparticles. The present article outlines our current understanding of TAG phase behavior in both bulk and emulsified systems. While our primary focus are investigations involving monoacid TAGs and their mixtures, we also include illustrative examples with natural TAG oils, highlighting the knowledge transfer from simple to intricate systems. Special attention is given to recent discoveries via X-ray scattering techniques. The main factors influencing TAG polymorphism are discussed, revealing that a higher occurrence of structural defects in the TAG structure always accelerates the rate of the α → β polymorphic transformation. Diverse approaches can be employed based on the specific system: incorporating foreign molecules or solid particles into bulk TAGs, reducing drop size in dispersed systems, or using surfactants that remain fluid during TAG particle crystallization, ensuring the necessary molecular mobility for the polymorphic transformation. Furthermore, we showcase the role of TAG polymorphism on a recently discovered phenomenon: the creation of nanoparticles as small as 20 nm from initial coarse emulsions without any mechanical energy input. This analysis underscores how the broader understanding of the TAG polymorphism can be effectively applied to comprehend and control previously unexplored processes of notable practical importance.

COGITO: A Coarse-Grained Force Field for the Simulation of Macroscopic Properties of Triacylglycerides

The use of molecular dynamics simulations is becoming ever more widespread; however, the application of this to pure triacylglyceride (TAG) systems is not. In this study, we are presenting the development, and validation, of a new force field (FF), which we have called the COarse-Grained Interchangeable Triacylglyceride-Optimized FF. The FF has been developed using both a bottom-up and top-down approach for different parameters, with the non-bonded parameters being optimized using a Bayesian optimization method. While the FF was developed using monounsaturated TAGs, results show that it is also suitable for fully saturated TAGs. Description of molecules which were not used during the development of the FF is carried out simply by interchanging the bead in the molecule topologies. Results show that the FF can reproduce the macroscopic properties (density and lattice parameters) of pure TAGs as both crystals and melt with high accuracy, as well as reproduce the differences in enthalpies.

Molecular dynamics simulation for mechanism revelation of the safety and nutrition of lipids and derivatives in food: State of the art

Molecular dynamics (MD) simulation has proved to be a powerful tool in the study of proteins, nucleic acids, lipids, and carbohydrates et al. in fields of health, nutrition, and food science. In particular, MD simulation has been employed in the investigation of various lipid systems such as triglycerides, phospholipid membranes, etc. Due to the continuous updating of computing resources and the development of new MD simulation methods and force field parameters, the simulation's time and size scale of lipids system has increased by several orders of magnitude. However, MD simulation cannot be used for systems invovle chemical reactions. These greatly limit its further application in the field of lipid research. This paper reviews the progress and development of MD simulation, especially for the application of MD simulation in different lipid systems. In this paper, MD simulation and its general workflow was briefly introduced firstly. Subsequently, the application of MD simulation in various lipid systems was reviewed in-depth. Finally, the limitation and future prospects of MD simulation in lipid research were also discussed. This review provided new insights into the investigation of MD simulation, and a novel thought for lipid study. We believe that MD simulation will exhibit more and more great advantages in the investigation of lipids in the future due to the development of novlel methods.

A Moving Boundary Model for Isothermal Drying and Shrinkage of Chayote Discoid Samples: Comparison between the Fully Analytical and the Shortcut Numerical Approaches

A moving boundary model for food isothermal drying and shrinkage is applied to predict the time decay of water content and sample volume, as well as water diffusivity for chayote discoid slices in the temperature range 40–70°C. The core of the model is the shrinkage velocity v, assumed equal to the water concentration gradient times a shrinkage function α representing the constitutive equation of the food material under investigation. The aim is to provide a case study to analyze and quantify differences and accuracies of two different approaches for determining the shrinkage function α from typical experimental data of moisture content X/X0 vs. rescaled volume V/V0: a fully analytical approach and a shortcut numerical one.