Self‐Assembly of Saturated and Unsaturated Phosphatidylcholine in Mineral and Vegetable Oils

• Published in: Journal of the American Oil Chemists' Society 2019-03, Vol.96 (3), p.273-289
• Main Authors: Martínez‐Ávila, Mariana, De la Peña‐Gil, Anaid, Álvarez‐Mitre, Flor M., Charó‐Alonso, Miriam A., Toro‐Vazquez, Jorge F.
• Format: Article
• Language: English
• Subjects: Liquid structure; Organogels; Phosphatidylcholine; Self‐assembly
• ISSN: 0003-021X; 1558-9331
• DOI: 10.1002/aocs.12188

We studied the molecular self‐assembly of commercial and pure‐saturated and pure‐unsaturated phosphatidylcholine (PtdCho) in vegetable (VO) and mineral (MO) oils. The PtdCho self‐assembly was monitored through rheology, differential scanning calorimtery (DSC), and polarized light microscopy. The results showed that in the presence of just the constituent water, the PtdCho self‐assembly occurred through the formation of a “liquid structure” stabilized by electrostatic interactions. The DSC measurements did not evidence the development of the “liquid structure.” However, the phase shift angle (δ) measured by rheology closely followed the PtdCho self‐assembly in both oils. The kinetics of the PtdCho self‐assembly and the crystal habit developed depended on the PtdCho solubility in the oil, the PtdCho purity, and the extent of unsaturation. Thus, the saturated PtdCho crystallized in the VO developing an organization of intertwined crystals that resulted in organogels with a true‐gel behavior (G′ of 12.2 × 105 to 16 × 105 Pa). In the MO, the saturated PtdCho crystallized in smaller microstructures developing organogels with higher G′, particularly with the commercial PtdCho (i.e., G′ of 32 × 105 Pa). With the unsaturated PtdCho, the presence of cis unsaturations favored the formation of inverted micelles in the VO and MO organogels. Thus, in contrast to the saturated PtdCho organogels, the unsaturated PtdCho organogels had lower G′ (30 × 102 to 45 × 102 Pa) with a gel‐like behavior.