EFFECT OF SORBITAN TRISTEARATE ON THE THERMAL AND STRUCTURAL-PROPERTIES OF MONOACID TRIGLYCERIDES - INFLUENCE OF A CIS OR TRANS DOUBLE-BOND

The influence of sorbitan tristearate (STS) on the thermal and structu ral properties of monoacid triglycerides, tristearin (SSS), trielaidin (EEE) and triolein (OOO), has been studied by differential scanning c alorimetry and powder X-ray diffraction at variable temperature. Resul ts coming from the polymorphic study show that, following a dynamic pr ocess, the effect of 5% in weight of STS on the crystalline transition s depends on the thermal behaviour of the triglycerides and more preci sely on the alpha --> beta' transformation way, i.e. solid state or me lt-mediated. The intersolubility between the triglycerides and STS has been determined from ''temperature versus composition'' binary phase diagrams. In each case, the interaction is of eutectic type. STS is pa rtially miscible into the considered triglyceridic lattices; a maximal solubility is reached into SSS, whereas OOO incorporates only small a mounts of the emulsifier.