8/2/2019 Crystallization Poster Rong1
1/1
Rong Liu
Supervisor: Dr. Gianfranco Mazzanti
Program: Food ScienceDegree :Master of Science
Edible oils and fats usually consist of a complexmixture of
triacylglycerols (TAGs), and the meltingrange is one of the main
factors which determinethe properties of fat. The melting range and
solidliquid phase behavior of fats are important in foodproducts
containing fats. TAGs has polymorphismin the solid phase. There are
three mainpolymorphs: ,,. In principle, the amount andcomposition
of a solid phase in fat can bedetermined by the thermodynamic
equilibrium(Wesdorp, 1990, p.486). Despite, many researcheffects to
predict the melting range and solidphase composition of fats from
the overall fat
composition, our ability to predict them is stillminimal. The
objective of this research is todescribe both phase equilibrium and
the solidcomposition of fats in a multiphase system. In thisstudy,
the Michelsen method is used to test thephase stability, and then
using the directsubstitution method to iterate
polymorphcrystallization procedures, and the Gibbs freeenergy
minimization using Murrays method isused for and polymorphs;
DSCmeasurements will be made to confirm thecalculation
results..
Abstract
Approach Methodology
Materialpreparation
the trilaurin (LLL) andtrimyristin (MMM)multiple system
the initialestimates andstability tests
The Michelsen method
Iteratingprocedures
Substitution method for polymorph
The Gibbs free energyminimization (Murraysmethod) for and
polymorphs.
Results confirm DSC measurement
Wesdorp, L.H. (1990) Liquid-multiplesolid phase equilibria in
fats:theory and experiment .A.G.Marangoni (ed.), Fat
crystalnetworks (pp.481-522). New York:Marcel Dekker.
Narine , S. S. and Marangoni, A.G.(1999). Fractal nature of
fatcrystal networks. Physical ReviewE,
59,1908-1920.doi:10.1103/PhysRevE.59.1908
Sato, K. (2001). Sato Crystallizationbehaviour of fats and
lipids- areview. Chemical engineeringscience, 56,
2255-2265.doi.org/10.1016/S0009-2509(00)00458-9
Introduction
The objective of this research is to describephase equilibrium
behaviour between a liquidphase and a number of solid solutions of
fats ina multiphase system. Determine the numberand amount of
coexisting phase and thecomposition of each phase.
Objective
(Wesdorp, 1990, p.508)
(Wesdorp, 1990, p.521)
1. The initial estimates and stability tests
MolarfreeGibbsenergyofmixing
Gibbs free energy of mixing as a function of composition
F is an unstable mixture and will demix A and B. Thetangent to
the curve at G lies at no point above the curve, soG represents a
stable mixture.
The curve of composition vs. Gibbs free energy, make suretangent
of all points are above the curve.
2. The direct substitution method for polymorph.
Calculate the P-1 phase fractions, and then to obtain thenew
compositions.
3. The Gibbs free energy minimization (Murrays method)for and
polymorphs.
Find the minimum of Gibbs free energy of and polymorphs.
4. DSC measurement
The experimental line for the triluarin andtrimyristin system
will be almost the sameas the calculated curve, showed as theabove
picture.
Expected Results
Reference
