Abstract:

The polymorphic behavior of 1,3-distearoyl-2-oleoyl glycerol (SOS) was investigated in the presence of a selected food emulsifier, sorbitan monostearate. Five polymorphs, named $\alpha$, $\gamma$, pseudo-$\beta$', $\beta$2, and $\beta$1, were crystd. and identified by x-ray anal. and DSC. Each polymorph was treated with 2 selected protocols - the screen cycle and the aging cycle. Sorbitan monostearate, when present in the molten fat, retarded the $\alpha$ to $\gamma$ transition during both the screen cycle and the aging cycle. A retardation effect was not detected for the $\gamma$ to pseudo-$\beta$' transition (during the screen or the aging cycle). The emulsifier inserted into the fat behaved as a conventional impurity, causing significant redn. in the melting temps. of each polymorph. As a result, the fat tended to melt prior to its transition. The behavior of SOS in the presence of the sorbitan monostearate is therefore different from that of SSS (tristearin), and may explain, in part, the absence of the strong blooming transition to high melting polymorph that occurs when the fat is rich in SOS. This behavior can also shed some light on the behavior of cocoa butter in the presence of sorbitan esters. [on SciFinder(R)]