Surface-Active Properties of Lipophilic Antioxidants Tyrosol and Hydroxytyrosol Fatty Acid Esters: A Potential Explanation for the Nonlinear Hypothesis of the Antioxidant Activity in Oil-in-Water Emulsions
| Autor: | Ricardo Lucas, Melanie Curcuroze, Olivia S. Maldonado, Juan C. Morales, Francisco Comelles, Jose Luis Parra, David Alcantara |
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| Rok vydání: | 2010 |
| Předmět: |
Antioxidant
Surface Properties Surfactants medicine.medical_treatment Antioxidants Oil in water Surface-Active Agents chemistry.chemical_compound Pulmonary surfactant Tyrosol medicine Organic chemistry Hydroxytyrosol chemistry.chemical_classification Lipophilic Chemistry Rational design Fatty acid Esters General Chemistry Phenylethyl Alcohol Chain length Emulsions General Agricultural and Biological Sciences Oils Surface activity |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 1520-5118 0021-8561 |
| DOI: | 10.1021/jf1009928 |
| Popis: | 6 páginas, 6 figuras, 1 tabla. Our group has recently observed a nonlinear tendency in antioxidant capacity of different hydroxytyrosol fatty acid esters in fish oil-in-water emulsions, where a maximum of antioxidant efficiency appeared for hydroxytyrosol octanoate. These results appear to disagree with the antioxidant polar paradox. Because the physical location of the antioxidants in an oil−water interface has been postulated as an important factor in explaining this behavior, we have prepared a series of tyrosol and hydroxytyrosol fatty acid esters with different chain length and studied their surface-active properties in water, because these physicochemical parameters could be directly related to the preferential placement at the interface. We have found that tyrosol and hydroxytyrosol fatty acid esters are relevant surfactants when the right hydrophilic−lipophilic balance (HLB) is attained and, in some cases, as efficient as emulsifiers commonly used in industry, such as Brij 30 or Tween 20. Moreover, a nonlinear dependency of surfactant effectiveness is observed with the increase in chain length of the lipophilic antioxidants. This tendency seems to fit quite well with the reported antioxidant activity in emulsions, and the best antioxidant of the series (hydroxytyrosol octanoate) is also a very effective surfactant. This potential explanation of the nonlinear hypothesis will help in the rational design of antioxidants used in oil-in-water emulsions. This work was supported by the Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC) with an Intramural Frontier Project (200680F0132) and a JAE-Doc Contract (to R.L.). |
| Databáze: | OpenAIRE |
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