Thermodynamics of partitioning of allyl isothiocyanate in oil/air, oil/water, and octanol/water systems

The thermodynamics of partitioning of allyl isothiocyanate (AITC) in oil/air, oil/water, and octanol/water systems were investigated using the van’t Hoff approach with olive and canola oils as model food oils. The partition coefficients were determined by phase ratio variation method at temperatures between 4 and 50 °C. AITC showed much stronger partitioning into oil or octanol phase than into air or water phase because of its strong hydrophobic nature. As temperature increased, the oil/air, oil/water, and octanol/water partition equilibria were shifted toward air, oil, and octanol phases, respectively. These partitioning behaviors are attributed that the air-to-oil transfer of AITC is an entropically unfavorable, enthalpy-driven spontaneous process, whereas both water-to-oil and water-to-octanol transfers are energetically unfavorable, entropy-driven spontaneous processes. Canola oil was found to be more effective as a solvent for AITC than olive oil in oil/air system but less effective in oil/water system.