Losada-Barreiro Sonia, Paiva-Martins Fátima, Bravo-Díaz Carlos
Departamento de Química-Física, Facultad de Química, Universidade de Vigo, 36310 Vigo, Spain.
REQUIMTE-LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal.
Antioxidants (Basel). 2024 May 11;13(5):593. doi: 10.3390/antiox13050593.
In this work, we aim to find physical evidence demonstrating the crucial role that the effective concentration of antioxidants (AOs) present at the interfacial region of emulsions has in controlling the inhibition of the lipid oxidation reaction. We prepared a series of antioxidants of different hydrophobicities derived from chlorogenic and protocatechuic acids. We first monitored, in intact emulsions, the (sigmoidal) production of conjugated dienes and determined the corresponding induction times, . Independently, we determined the effective concentrations of the antioxidants in the same intact emulsions. Results show that both the length of the induction periods and the antioxidant interfacial concentrations parallel each other, with a maximum at the octyl-dodecyl derivatives. The ratio between the interfacial antioxidant concentrations and the induction periods remains constant for all AOs in the same series, so that the rates of initiation of lipid oxidation are the same regardless of the hydrophobicity of the antioxidant employed. The constancy in the rate of initiation provides strong experimental evidence for a direct relationship between interfacial concentrations and antioxidant efficiencies. Results suggest new possibilities to investigate lipid peroxidation under non-forced conditions and are of interest to formulators interested in preparing emulsions with antimicrobial properties.
在这项工作中，我们旨在找到物理证据，以证明乳液界面区域存在的抗氧化剂（AO）有效浓度在控制脂质氧化反应抑制方面所起的关键作用。我们制备了一系列源自绿原酸和原儿茶酸的不同疏水性抗氧化剂。我们首先在完整乳液中监测共轭二烯的（S形）生成，并确定相应的诱导时间。独立地，我们测定了相同完整乳液中抗氧化剂的有效浓度。结果表明，诱导期的长度和抗氧化剂的界面浓度相互平行，在辛基 - 十二烷基衍生物处达到最大值。同一系列中所有AO的界面抗氧化剂浓度与诱导期之间的比率保持恒定，因此无论所用抗氧化剂的疏水性如何，脂质氧化的引发速率都是相同的。引发速率的恒定性为界面浓度与抗氧化剂效率之间的直接关系提供了有力的实验证据。结果为在非强制条件下研究脂质过氧化提供了新的可能性，并且对于有兴趣制备具有抗菌特性乳液的配方设计师来说具有重要意义。
