Time, Temperature, and Concentration Dependence of Ricinelaidic Acid–Canola Oil Organogelation

Abstract

Canola oil (CO) gels were formed using ricinelaidic acid (REA), a hydroxylated fatty acid, and the time, temperature, and concentration dependence of the resulting gel structure was studied using small-deformation rheology, light microscopy, and powder X-ray diffraction (XRD). Between 5 °C and 30 °C, REA concentration had a significant influence on gel elasticity (P < 0.05), whereas temperature had a relatively lesser influence on gel rheology. Differences were observed in the scaling exponent of G′_LVR with concentration above 20 °C, which were also correlated with significant differences in gelation time at 20 °C. However, the 5% gels at 5 °C, 20 °C, and 35 °C displayed similar microstructures and behaved like weak gels stabilized by junction zones. Most of the gels studied (i.e., the 2%, 3%, 4%, and 5% gels at 15 °C, 20 °C, and 25 °C) consisted of long, thin, fibrous REA strands, although at 25 °C, the 2% gel was characterized by more transient and circular entities. During 28 days’ storage, there were no apparent changes detected in gel microstructure by microscopy or XRD, despite increases in the gel’s opacity.