@@HomeΙίι@@_ΆΪΙίι
Chocolate consists of solid particles such as cocoa, sugar,
and milk solids that are dispersed in a continuous fat phase.
So, the physical properties of chocolate are mainly influenced by
the crystallographic properties of the fat phase. The fat
usually used in chocolate is cocoa butter, which involves three
symmetric triacyglycerols (TAGs), 1,3-dipalmitoyl-2-oleoylglyce-
rol (POP), 1,3-distearoyl-2-oleoylglycerol (SOS), and 2-oleoyl-
stearoylpalmitoylglycerol (POS). Melt crystallization of inde-
pendent polymorphs of above three TAGs was studied precisely
with pure samples and obtained three common results, a) rates
of crystallization were always higher in less stable polymorphs,
b)rates of crystallization was higher in melt-mediated crystalli-
zation, and c) the occurrence of polymorphs was differ by crystal-
lization mode used. The crystallization properties of ternary
systems of POP, POS and SOS were also examined and discussed
how to get the desired property by changing the concentration
ratio of these three TAGs.
Another attempt had done to change the physical properties
of chocolate by using newly developed TAG, OSO (1,3-dioleoyl-2-
stearoylglycerol). OSO was prepared by interesterification of
SSS (tristearoylglycerol) and OOO (trioleoylglycerol) by enzyme
and purified by preparative HPLC. The phase behaviors of the
mixtures of SOS and OSO were studied and the formation of a
molecular compound was confirmed at the mixture of equal weight
ratio. This compound was revealed to have a double chain length
structure in stable polymorph, in which stearoyl and oleoyl -
chains were segregated each other. Compound formation was also
occurred by mixing OSO and cocoa butter, which showed very plas-
tic and flexible properties than cocoa butter itself, yet melting
point was almost the same as cocoa butter. This phenomenon was
observed in OSO containing chocolate, and the possible mechanism
of softening effect was discussed based on the relationship of
double chain length lamellar structures to lamellar slipping
movement induced by the incorporation of liquid oil at the lamel-
lar interface.
Key words;triacylglycerol, crystallization, cocoa butter,
chocolate,compound