《Binary Phase Behavior of 1》.pdf
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J Amer Oil Chem Soc (2007) 84:219–227
DOI 10.1007/s11746-006-1034-0
ORIGINAL PAPER
Binary Phase Behavior of 1,3-Dipalmitoyl-2-oleoyl-sn-glycerol
and 1,2-Dioleoyl-3-palmitoyl-rac-glycerol
L. Zhang Æ S. Ueno Æ S. Miura Æ K. Sato
Received: 9 August 2006 / Accepted: 15 December 2006 / Published online: 23 January 2007
AOCS 2007
Abstract 1,3-Dipalmitoyl-2-oleoyl-sn-glycerol (POP) formed. A time-resolved synchrotron radiation X-ray
and 1,2-dioleoyl-3-palmitoyl-rac-glycerol (OOP) are diffraction study undertaken during the cooling and
two major molecular species that account for roughly heating processes indicated that the a and b¢ forms of
half of the total triacylglycerols in palm oil. The the POP and OOP fractions crystallized and melted in
binary phase behavior of a POP/OOP mixture plays separate manners, and that crystallization of the b¢
an important role in the crystallization of palm oil. form and the polymorphic transformation from a to b¢
We conducted thermodynamic and kinetic studies of of POP and OOP are promoted in the presence of
OOP and its mixtures with POP using differential another component. The absence of molecular com-
scanning calorimetry and X-ray diffraction with a pound crystals in the binary mixtures of POP/OOP is
conventional generator and synchrotron radiation. We explained by taking into account the molecular
found that OOP has two polymorphs, a as a meta- interactions of acyl chain packing, glycerol confor-
stable form and b¢ as the most stable form, and that mation, and methyl end stacking, among which glyc-
the two forms are stacked in a triple-chain-length erol conformation appeared to be most influential.
structure. The POP/OOP mixtures exhib
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