INSTITUTO DE TECNOLOGIA EN POLIMEROS Y NANOTECNOLOGIA
Unidad Ejecutora - UE
In situ synchrotron radiation X-ray scattering study on the effect of a stearic sucrose ester on polymorphic behavior of a new sunflower oil variety
JAIME A RINCON CARDONA; LINA MARCELA AGUDELO LAVERDE; SILVANA MARTINI; ROBERTO J CANDAL; MARIA LIDIA HERRERA
FOOD RESEARCH INTERNATIONAL
ELSEVIER SCIENCE BV
Lugar: Amsterdam; Año: 2014 vol. 64 p. 9 - 17
The effect of the stearic sucrose ester (SE) S-170 on crystallization behavior and polymorphism of two stearins obtained from a new variety of high stearic high oleic sunflower oil was studied by pulsed nuclear magnetic resonance (p-NMR), small (SAXS) and wide (WAXS) angle X-ray scattering using synchrotron light and differential scanning calorimetry (DSC). p-NMR studies showed that there is always a crystallization temperature below which the effect is acceleration of crystallization and above which the effect is delay of nucleation and growth. The effect of SE S-170 strongly depended on supercooling. It was efficient as a seed for high supercooling (low crystallization temperatures) but this efficiency diminished at low supercooling (temperatures close to the melting point) when a few crystals were formed. SAXS and WAXS results demonstrated that depending on crystallization temperature SE S-170 promoted crystallization of and forms with more polymorphic similarity and inhibited occurrence of ? forms specially the ?2 polymorph. In some conditions SE S-170 favored crystallization of ?1 polymorph. DSC experiments showed that SE S-170 significantly diminished total melting enthalpies when the effect was delayed of crystallization. For other conditions no significant differences were found in melting temperatures or total melting enthalpies. When stearins were stored at 25°C, crystallization in the 2 form was promoted. Depending on crystallization temperature polymorphic forms ?1 and 2 may be obtained as the main polymorphic forms. This is very relevant from the technological point of view. Depending on the application, SE S-170 may help obtaining the required polymorphic form: ?1 form for spreads and 2 polymorph for chocolate production.