Journal of the American Oil Chemists’ Society

, Volume 67, Issue 11, pp 879–882 | Cite as

A study of the kinetics of nucleation in a palm oil melt

  • W. L. Ng
Technical

Abstract

Nucleation from a supercooled melt of palm oil was studied by optical microscopy and differential scanning calorimetry (DSC). Despite being a multicomponent system, palm oil exhibits a rather simple cooling thermogram with its high- and low-T exotherms exclusively related to the “hard” and “soft” components of the oil. As the “hard” components are being removed, the position of the high-T peak shifts down toward the low-T peak with diminishing peak intensity, while the position of the latter remains virtually unchanged.

At 288°K, nucleation in a palm oil melt is instantaneous. Its induction time-temperature curve shows an abrupt discontinuity at 297°K, which demarcates the occurrence of one polymorph from another. Nucleation data fit very well into the Fisher-Turnbull equation. Its larger activation free energy of nucleation is accompanied by lowering of the melting point and an increase in the crystal/melt interfacial free energy as compared to palm stearin. The slow rate of nucleation in palm oil is attributed to intermolecular interaction between its “hard” and “soft” components.

key words

Nucleation kinetics palm oil melt 

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References

  1. 1.
    Taylor, A.M..Oleagineux 31:73 (1976).Google Scholar
  2. 2.
    Russell, J.B.:J. Am. Oil Chem. Soc. 52:505 (1975).Google Scholar
  3. 3.
    Persmark, U., K.A. Melin and P.O. Stahl,Rev. Ital. Del. Soc. Gra. LIII:301, (1976).Google Scholar
  4. 4.
    Kawamura, K.,J. Am. Oil Chem. Soc. 56:753 (1979).Google Scholar
  5. 5.
    Kawamura, K.,Ibid., 57:48 (1980).Google Scholar
  6. 6.
    van Putte, K.P.A.M., and B.H. Bakker,Ibid. 64:1138 (1987).Google Scholar
  7. 7.
    Ng, W.L.,Ibid., 66:1103 (1989).Google Scholar
  8. 8.
    Small, D.M., inHandbook of Lipid Research: The Physical Chemistry of Lipids, vol. 4, Plenum Press, New York, 1986, p. 347.Google Scholar
  9. 9.
    Brice, J.C., inSelected topics in solid State Physics: The Growth of Crystals from Liquids, Vol. XII, North-Holland, Amsterdam, London, 1973, p. 94.Google Scholar
  10. 10.
    Woodruff, D.P., inThe Solid-Liquid Interface, Cambridge University Press, London, 1973, p. 22.Google Scholar
  11. 11.
    Mullin, J.W., and H.M. Ang,Dis. Faraday Soc. 61:141 (1976).CrossRefGoogle Scholar
  12. 12.
    Strickland-Constable, R.F., inKinetics and Mechanism of Crystallization, Academic Press, London, 1968, p. 95.Google Scholar

Copyright information

© AOCS Press 1990

Authors and Affiliations

  • W. L. Ng
    • 1
  1. 1.Department of ChemistryUniversity of Malaya, Pantai ValleyKuala LumpurMalaysia

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