Influence of AO chain length, droplet size and oil to water ratio on the distribution and on the activity of gallates in fish oil-in-water emulsified systems: Emulsion and nanoemulsion comparison

Abstract

The distribution of a homologous series of polyphenol derivatives of increasing lipophilicity has been determined in fish oil-in-water emulsions and nanoemulsions by the pseudophase model. One of the hypotheses on which the pseudophase model is based, is that its application is independent of the size of emulsion droplets. In agreement with our hypothesis, results showed that the smaller droplet size found in nanoemulsions does not affect partition constants of gallic acid (GA) and its esters. The antioxidant efficiency of GA and gallates in the emulsified systems used, correlated positively with the concentration of antioxidant at the interfacial region. The increase in the oil/water ratio increased the overall oxidative stability of emulsions but decreased the antioxidant efficiency of the more lipophilic derivatives. This can be assigned to the fact that, increasing the oil phase volume, the interfacial concentration decreased for the more lipophilic antioxidants.

Interfacial Concentrations of Hydroxytyrosol Derivatives in Fish Oil-in-Water Emulsions and Nanoemulsions and Its Influence on Their Lipid Oxidation: Droplet Size Effects

“…Based on our previous results and on the application of the pseudophase kinetic model, which presumes that droplet size does not affect antioxidant distributions and hence antioxidant efficiencies, [15,[25][26][27] we hypothesize that the interfacial antioxidant concentrations are not affected by the droplet size. To prove, or discard, our hypothesis, we undertook a thorough investigation by employing fish oil-in-water emulsions and nanoemulsions with the same chemical composition but different droplet sizes (ranging from~166 nm to~4600 nm).…”

“…As in previous works, the droplet size, ζ-potential (the electrical potential at the slipping interface), and polydispersity (as measured by the polydispersity index, defined as the mass average over the number average particle radius) of fresh HEn 4:6 O/W emulsions and 1:9 O/W emulsions and nanoemulsions were determined by employing a dynamic light scattering (DLS) Zetasizer (NanoZS laser diffractometer Malvern Instruments Ltd., Worcestershire, UK) at T = 25 • C [15].…”

“…By applying the pseudophase kinetic model, we previously determined the effective concentration of AOs in the interfacial region of intact emulsified systems, thus demonstrating that there is a direct relationship between the interfacial concentrations and their antioxidant efficiencies [12,14,15]. The pseudophase kinetic model assumes that antioxidants partition thermodynamically between the different regions of emulsions and are in dynamic equilibrium [15]. Thus, their effective concentration in each region depends on the solvent properties of each region but not on the size of By applying the pseudophase kinetic model, we previously determined the effective concentration of AOs in the interfacial region of intact emulsified systems, thus demonstrating that there is a direct relationship between the interfacial concentrations and their antioxidant efficiencies [12,14,15].…”

“…The pseudophase kinetic model assumes that antioxidants partition thermodynamically between the different regions of emulsions and are in dynamic equilibrium [15]. Thus, their effective concentration in each region depends on the solvent properties of each region but not on the size of By applying the pseudophase kinetic model, we previously determined the effective concentration of AOs in the interfacial region of intact emulsified systems, thus demonstrating that there is a direct relationship between the interfacial concentrations and their antioxidant efficiencies [12,14,15]. The pseudophase kinetic model assumes that antioxidants partition thermodynamically between the different regions of emulsions and are in dynamic equilibrium [15].…”

Improving the Stability of Lycopene from Chemical Degradation in Model Beverage Emulsions: Impact of Hydrophilic Group Size of Emulsifier and Antioxidant Polarity

“…According to the previous study [21], among the free radical scavengers, oil soluble antioxidants (α-tocopherol) were more effective in increasing the lycopene stability in emulsions than were surface-active antioxidants (propyl gallate). However, as described above, since antioxidants having suitable hydrophilic-lipophilic balance values can be more concentrated at the interfacial region of emulsions as the main site of lipid oxidation and the degradation of lipophilic functional compounds, amphiphilic antioxidants are more effective than strongly hydrophobic and hydrophilic antioxidants in the prevention and/or inhibition of lipid oxidation and the degradation of lipophilic functional compounds [47,48]. Also, since the radical scavenging activity of TBHQ was lower than that of lauryl gallate, it was expected that lauryl gallate showed a better ability to inhibiting lycopene degradation than TBHQ.…”