Departamento Química Física, Facultad Química, Universidad de Vigo, 36200 Vigo, Spain.
J Agric Food Chem. 2013 Jul 3;61(26):6533-43. doi: 10.1021/jf400981x. Epub 2013 Jun 18.
Antioxidant (AO) efficiencies are reported to go through maxima with increasing chain length (hydrophobicity) in emulsions. The so-called "cutoff" after the maxima, indicating a decrease in efficiency, remains unexplained. This paper shows, for gallic acid (GA) and propyl, octyl, and lauryl gallates (PG, OG, and LG, respectively), that at any given volume fraction of emulsifier, the concentrations of antioxidants in the interfacial region of stripped corn oil emulsions and their efficiency order follow PG > GA > OG > LG. These results provide clear evidence that an AO's efficiency correlates with its fraction in the interfacial region. AO distributions were obtained in intact emulsions by using the pseudophase kinetic model to interpret changes in observed rate constants of the AOs with a chemical probe, and their efficiencies were measured by employing the Schaal oven test. The model provides a natural explanation for the maxima with increasing AO hydrophobicity.
抗氧化剂（AO）效率据报道在乳液中随链长（疏水性）的增加而呈现最大值。最大值之后的所谓“截止”，表明效率降低，但原因仍未得到解释。本文以没食子酸（GA）和丙基、辛基和月桂基没食子酸酯（PG、OG 和 LG）为例，表明在任何给定的乳化剂体积分数下，抗氧化剂在脱去油玉米乳液的界面区域的浓度及其效率顺序为 PG>GA>OG>LG。这些结果清楚地表明，抗氧化剂的效率与其在界面区域的分数相关。通过使用假相动力学模型来解释化学探针观察到的抗氧化剂速率常数的变化，在完整的乳液中获得了抗氧化剂的分布，并且通过使用 Schaal 烘箱测试来测量它们的效率。该模型为 AO 疏水性增加的最大值提供了自然的解释。
