Distributions of phenolic acid antioxidants between the interfacial and aqueous regions of corn oil emulsions—a commentary

Abstract

Being capable of optimizing the usage of antioxidants is a challenge for any industry concerned with formulating food and non‐food products because it will affect its competitiveness and the product's attractiveness in response to consumer demand. This is also a challenge for scientists who remain puzzled by the unpredictable oxidative behavior of real, complex food, and non‐food matrices. Laurence Romsted and Carlos Bravo‐Diaz have developed some years ago a pseudophase kinetic model to determine the partitioning of chain‐breaking antioxidants in micellar systems and emulsions stabilized by surfactants. In this article, with Sonia Lasada‐Barreiro they used the pseudophase model to determine the partitioning of two phenolic antioxidants (gallic acid and caffeic acid) in a model oil‐in‐water emulsion with increasing surfactant concentrations and at different pH values. This commentary underlines the importance of the pseudo‐phase model and the present work to achieve a better use of antioxidants. It is also suggested that the enigma of antioxidant efficiency in complex systems is far from completely solved.

Antioxidant Behavior of Olive Phenolics in Oil-in-Water Emulsions

“…Even though existing methods for evaluating antioxidant partitioning in intact emulsions that refer to the pseudophase model are available, in this work the partitioning was conducted in the continuous phase after emulsion separation, also considering the fact that both the radical initiator AAPH and Fremy’s radical for EPR measurements were water-soluble. This approach, though providing partial information, has been frequently adopted in the literature and can contribute to the interpretation of antioxidant behavior. ,− Moreover, the pseudophase model, despite being widely used in surfactant-stabilized model emulsions, needs to be further validated in more complex systems such as protein-stabilized emulsions . The partitioning of the olive phenolic antioxidants in the continuous phase as affected by emulsion formulation is reported in Figure .…”

“…11,38−40 Moreover, the pseudophase model, despite being widely used in surfactant-stabilized model emulsions, needs to be further validated in more complex systems such as proteinstabilized emulsions. 41 The partitioning of the olive phenolic antioxidants in the continuous phase as affected by emulsion formulation is reported in Figure 2. Among the compounds, tyrosol showed the greatest partitioning in the aqueous phase of the MD0 emulsions, while oleuropein and hydroxytyrosol partitioned poorly with similar percentages (23−27%).…”

Lipid formulations, structuring, and crystallization

“…The paper of Bravo‐Díaz et al addresses the effects of pH and emulsifier concentration on the distributions of phenolic acid antioxidants between the interfacial and aqueous regions of corn oil emulsions. The paper has motivated a commentary from C. Genot .…”