Solubility of Bioactive Substances in Ethyl Lactate + Water Mixtures: Ferulic Acid and Caffeine
David Villanueva-Bermejo1, *, Guillermo Reglero1, Roumiana P. Stateva2, Tiziana Fornari1
1 Instituto de Investigación en Ciencias de la Alimentación CIAL (CSIC-UAM). C/Nicolás Cabrera 9, Universidad Autónoma de Madrid, 28049 Madrid, Spain
2 Institute of Chemical Engineering, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
The solubility of ferulic acid in ethyl lactate + water mixtures was measured at ambient temperature and pressure, and reported for the first time in this work. It was demonstrated that the acid solubility in the respective mixed solvents was considerably higher than in either pure ethyl lactate or water. Similar behavior pattern was recently reported by the authors for the solubility of caffeine in ethyl lactate + water mixtures.
UNIQUAC and modified UNIFAC (Dortmund) were applied to represent the solubility of ferulic acid and caffeine in the mixed solvents and their capabilities to describe adequately the cosolvent effect observed was tested and compared. The results obtained demonstrated that the UNIQUAC model provided excellent correlation of the experimental data for both systems. The UNIFAC model, on the other hand, was applied in a completely predictive manner and produced very good results for ferulic acid solubility and just qualitative predictions for caffeine.
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