Comparison of predicted and experimental DSC curves for vegetable oils

We compare experimental and predicted differential scanning calorimetry (DSC) curves for palm oil(PO), peanut oil (PeO) and grapeseed oil (GO). The predicted curves are computed from the solid–liquid equilibrium modelling and direct minimization of the Gibbs free energy. For PO, the lower the scan rate, the better the agreement. The temperature transitions of PeO and GO were predicted with an average deviation of −0.72°C and −1.29°C respectively, in relation to experimental data from literature. However, the predicted curves showed other peaks not reported experimentally, as computed DSC curves correspond to equilibrium hypothesis which is reached experimentally for an infinitely small scan rate. The results revealed that predicted transitions temperatures using equilibrium hypotheses can be useful in pre-experimental evaluation of vegetable oils formulations seeking for desired melting profiles

Computer-Aided Lipid Design: phase equilibrium modeling for product design

The aim of this work is use phase equilibrium modeling as an auxiliary tool for product design, especially for those whose desired final properties are directly related to solid fat content (SFC) and melting behaviour. Solid-liquid equilibrium (SLE) modeling has been implemented for triacylglycerols mixtures, the main components of vegetable oils, a renewable raw-material for a wide variety of products. Excess Gibbs energy models were used to model solid-phases while direct optimization of Gibbs free energy using Generalized Reduced Gradient was performed aiming to compute the number of molecules in each phases at the whole range of melting. As results, a computed phase diagram was compared with experimental data from literature as well as a DSC curve. The model was also used to simulate a four-component DSC curve as a predictive tool

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

Solid-liquid phase equilibrium modeling of triacylglycerols mixtures is essential for lipids design. Considering the α polymorphism and liquid phase as ideal, the Margules 2-suffix excess Gibbs energy model with predictive binary parameter correlations describes the non ideal β and β’ solid polymorphs. Solving by direct optimization of the Gibbs free energy enables 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-sn-glycerol (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-Long-Medium type structured lipids is evaluated, using caprylic acid as medium chain and long chain fatty acids (EPA-eicosapentaenoic acid, DHA-docosahexaenoic acid, γ-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. γ-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 Equilibria Modelling for triacylglycerols exhibiting multiple solid phases

Important end-use properties of vegetable oils based edible products are strong related to the equilibrium between a solid crystalline network and a liquid phase. This work presents the available literature development of solid-liquid equilibrium in triacylglycerol systems and highlights how it can be coupled with a Computer-Aided Mixture and Blend Design framework, for design new mixtures/blends with improved properties allowing a better use of renewable resources as vegetable oils. Stability tests were implemented as they are an essential step for powerful solid liquid equilibrium resolution and some results were presented for a four component triacylglycerol mixture in different temperatures and composition

Solid Fat Content of Vegetable Oils and Simulation of Interesterification Reaction: Predictions from Thermodynamic Approach

The Solid Fat Content (SFC) of vegetable oils is a fundamental property in fatty foods. Also, chemical interesterification (the exchange of fatty acids within and between triacylglycerols) has been used to enhance the melting profile of vegetable oils blends used in food industry. The present work uses a computational approach using Solid–Liquid Equilibrium (SLE) to predict SFC and simulate the chemical interesterification reaction (CI) for different formulations using palm oil (PO), sunflower oil (SFO) and palm kernel oil (PKO). More than 3696 SLE problems are solved, allowing the evaluation of how the fraction of each oil, the temperature and the CI reaction impacts the SFC. The calculated SFC values are compared with experimental data taken from literature. For systems composed of two or one single vegetable oil, the average absolute error (AAE) is 5.2% before CI and 4.2% after CI. For systems composed of three vegetable oils, the AAE is 6.3% before CI and 4.2% after CI. The predictions of SFC before and after CI reaction can aid the food makers to face the combinatorial problem imposed by the choice of the vegetable oil and its fraction in the blend. Future improvements in the pure component properties, thermodynamic model and distribution model of fatty acids in the triacylglycerols can increase the use of computational approaches allowing the experiments to be focused on the most promising formulations in terms of melting profil

Vegetable oil modeling applied for the formulation of structured lipids

Vegetable oils are complex mixtures composed mainly by triglycerides, which in turn are made of three fatty acids sterified on a glycerol backbone. They display both physical and nutritional properties that make them appealing for the food industry and the human consumption. Concerning nutrition and health issues, vegetable oils can bear polyunsaturated fatty acids (PUFA) in sn-2 position of the glycerol, and such triglycerides are reputed healthier than animal fat, cold water fish’s ones excepted. Food engineers seek vegetable oils formulations that have fatty acids with enhanced nutritional profile while keeping physical properties within the desired range. Besides, special fatty acids, like omega 3,6 and 9 are looked at in sn-2 position and can add value to food products based on vegetable oils. Concerning consumers’ desired attributes in fat-foods like hardness, texture, graininess and spreadability, they are strongly related to the distribution of the triglycerides between the solid and liquid phases (solid fat content). As physical and nutritional properties are both related to the oil composition and physical state, we model the solid – liquid equilibrium of vegetable oils by using up-to-date thermodynamic concepts and show how this can be used to evaluate in a pre-experimental step how composition impacts the melting profile. The model is predictive and uses triglycerides or fatty acid composition, the last one being easier to measure. Computing solid fat content curves and DSC curves, allows us to predict the outcome of vegetable oil mixtures, the impact of introducing omega fatty acids on oil, but also the result of chemical interesterification of a vegetable oil mixture

Modeling and simulation of melting curves and chemical interesterification of binary blends of vegetable oils

A Solid Liquid Equilibrium model coupled with analgorithm for direct minimization of the Gibbs free energy function was used to compute the melting profiles for binary blends of vegetable oils. The effect of interest erification on the Solid Fat Content (SFC) is simulated by using a completely random distribution of fatty acids on the glycerol structures. The methodology was applied to different blends of 6 vegetable oils: canola oil, fully hydrogen ated palm oils tear in, palm oils tear in, cotton seed oil, milk fat and corn oil. The predicted results were compared with experimental data from literature and the average absolute error in SFC was 3.33 (physical mixture without interesterification) and 4.13% (after interesterification). Additionally, two qualitative aspects also observed inexperimental works could be computationally detected: the existence of temperatures in which the blends have the same SFC before and after reaction and the fact that randomized blends tend to melt at lower temperatures than their corresponding mixtures. The results reinforced the potential use of computer-based tools to explore new formulations aiming to match a desired melting range, reducing the experimental efforts in product design where vegetable oils are used and the thermal profile has a fundamental role

Weblab France-Brésil en génie des procédés

A Weblab is an experiment remotely operated via internet. A Weblab between the Chemical Engineering Department of the University of São Paulo Polytechnic School (EPUSP) and the Process Engineering Department of the Ecole Nationale Supérieurs d’Ingénieurs en Arts Chimiques et Technologiques (ENSIACET) is developed. The experiment consists of a tank level control. The main objective is to propose and test tunings for the system control loop. For this purpose, the students must work in synergy and propose models for the system in order to find the tuning parameters. Weblab is a showcase for new technologies and original experiences because it allows to perform a control action from anywhere in a supervision environment which is spreading out in the industry. The objectives and interests are mainly pedagogical as the Weblab favours the variety and diversity of intercultural experiences a student could experience during his undergraduate studies. Because of this, the Weblab perfectly integrates in an engineer curriculum that is open to international exchanges. Un WebLab est une installation commandée à distance via internet. Nous développons une expérience de Weblab entre le département de Génie Chimique de l’Ecole Polytechnique de l’Université de São Paulo (EPUSP) et le département Génie des Procédés et Informatique de l’Ecole Nationale Supérieurs d’Ingénieurs en Arts Chimiques et Technologiques (ENSIACET). L’expérience consiste en la régulation de niveau dans un bac. L’objectif de l’expérience est de proposer et de valider des réglages pour la boucle de commande du système. Pour cela, les étudiants de l’EPUSP et de l’ENSIACET doivent travailler en synergie et proposer des modélisations et un réglage du contrôleur. Le Weblab constitue une vitrine de technologies innovantes et d’expériences originales, car il permet, depuis n’importe où, d’effectuer une commande à distance dans un environnement de supervision qui est de plus en plus adopté dans l’industrie. Les objectifs et intérêts du WebLab se situent plutôt au niveau pédagogique car il peut être un facteur multiplicatif du nombre d’expériences interculturelles pouvant être vécues par un étudiant tout au long de son cursus. Pour ces raisons le Weblab s’intègre parfaitement dans une formation d’ingénieurs qui se doit d’être ouverte à l’international

Dynamics of reactive distillation for the production of ethyl acetate: experiments at a pilot plant and modelling

In order to understand the complex behaviour of the reactive distillation process and to be able to provide an accurate design of a reactive column, detailed analyses on both continuous and transient regime become necessary. The objective is the definition of a reliable simulation model, based on experimental data obtained from a real pilot-scale plant device for the heterogeneously catalysed esterification of acetic acid and ethanol to form ethyl acetate and water. The choice of the parameters for the continuous equilibrium model was discussed and the simulation results provided good agreement with experimental data, revealing an interesting sensitivity of the catalyst activity to the feed composition. Once column configuration and operational parameters were validated, dynamic experiments were realized so as to interpret the sensitivity of different disturbances. Feed flow rates, reflux ratio and heat duty were perturbed and the consequent open loop transient responses were identified. The assessment of hydrodynamic parameters and the validation of the transient data allow the definition of a reliable dynamic model that represents tendencies and behaviours of the process well. The resulting model is to be applied into a more complex controllability methodolog