Phase Equilibrium and Optimization Tools: Application for Enhanced Structured Lipids for Foods

Abstract

Solid-liquid phase equilibrium modeling of triacylglycerol mixtures is essential for lipids design. Considering the a polymorphism and liquid phase as ideal, the Margules 2-suffix excess Gibbs energy model with predictive binary parameter correlations describes the non ideal b and b 0 solid polymorphs. Solving by direct optimization of the Gibbs free energy enables one to predict from a bulk mixture composition the phases composition at a given temperature and thus the SFC curve, the melting profile and the Differential Scanning Calorimetry (DSC) curve that are related to end-user lipid properties. Phase diagram, SFC and DSC curve experimental data are qualitatively and quantitatively well predicted for the binary mixture 1,3-dipalmitoyl-2-oleoyl-sn-glycerol (POP) and 1,2,3-tripalmitoyl-sn-glycerol (PPP), the ternary mixture 1,3-dimyristoyl-2-palmitoyl-snglycerol (MPM), 1,2-distearoyl-3-oleoyl-sn-glycerol (SSO) and 1,2,3-trioleoyl-sn-glycerol (OOO), for palm oil and cocoa butter. Then, addition to palm oil of Medium-LongMedium type structured lipids is evaluated, using caprylic acid as medium chain and long chain fatty acids (EPAeicosapentaenoic acid, DHA-docosahexaenoic acid, c-linolenic-octadecatrienoic acid and AA-arachidonic acid), as sn-2 substitutes. EPA, DHA and AA increase the melting range on both the fusion and crystallization side. c-linolenic shifts the melting range upwards. This predictive tool is useful for the pre-screening of lipids matching desired properties set a priori.

Solid-liquid equilibrium of triolein with fatty alcohols

“…Some data on solid-liquid transitions of fatty mixtures, phase diagrams and pure component properties using this technique, including TAGs, fatty acids, esters and alcohols, can be found in the literature (Wesdorp, 1990;Costa et al, 2007Costa et al, , 2009Costa et al, , 2010aCosta et al, , 2010bCosta et al, , 2011Carareto et al, 2011). The phase transition behavior can be modeled by solving a system of equations based on the conditions of thermodynamic equilibrium (Wesdorp, 1990;Dos Santos et al, 2011). Several approaches for this…”

Trends and demands in the solid–liquid equilibrium of lipidic mixtures

“…This process is a classical alternative for the replacement of the hydrogenation procedure which promotes the formation of saturated or trans-unsaturated fatty compounds 55 related as precursors of cardiovascular diseases 10 ; c) Development of structured lipids for the improvement of the nutritional or physicochemical characteristics of the product. This process involves chemical or enzymatic pathways and is aimed at the modification of the triacylglycerols' fatty acid profile 38 ; d) 60 Control of crystallization phenomena in lubricants or oils for frying processes, in which solid particles or even compounds that could promote crystallization are undesirable or in butters, creams and analogous products, in which the crystalline structure is responsible for the desired texture 5, 6, 27, 48 65 Other special cases take into account the production of new materials for the applications in food, pharmaceutical, materials or energy industries. Mixtures of fatty acids and fatty alcohols, for example, had been evaluated for the formulation of organogels 90,91 and phase change materials [92][93][94] .…”

“…Despite the fact that solid solutions are more common than usually admitted, most authors have adopted the modeling 55 approach based on the solid phase immiscibility. In the works that take into account a more comprehensive approach and consider the formation of such solid solutions 4,38,96 two main focuses can be identified. From the academic focus, the solidliquid equilibrium theory is formulated for complete description 60 of the solid-liquid phase diagram of a system of interest, this means for calculating the liquidus and the solidus lines.…”

“…By changing 80 the fatty acid composition of triacylglycerols it is possible to improve specific properties 38 . High amounts of saturated or trans-unsaturated fatty acids can, for instance, bring negative effects concerning the nutritional claim of the product and, additionally, can increase its melting point.…”

“…Comprising multiple solid phases at the same temperature and pressure condition, literature very frequently fails to correctly describing the phase behavior of these mixtures 35 and this becomes worst as more complex behaviors are observed. What makes the SLE of fatty mixtures so particular is their inherent ability to polymorphism phenomena 4,7,37,38 . It means that the long-hydrocarbon chains of the fatty compounds and consequently their crystal lattice can be configured into numerous 40 micro-and macromolecular arrangements, directly related to the thermal treatment to which the mixture is submitted.…”