Comparative Electrochemical Determination of Total Antioxidant Activity in Infant Formula with Breast Milk

Abstract

The aim of this study is to investigate the significance of breast milk and infant formula in the prevention of oxidative stress, by electrochemical determination of the total antioxidant potential, demonstrating the relationship between the antioxidant capacity of milk and postnatal age. Human breast milk, commercial UHT milk, and infant formulas supplemented with prebiotics were used. Samples were diluted in phosphate buffer solution, and the total antioxidant activity was potentiometrically measured by the iodine/iodide redox couple with the Pt Fisher electrode as a working electrode and saturated calomel as a reference electrode. Cyclic voltammograms and differential pulse voltammograms were recorded with the glassy carbon electrode as the working electrode, an accessory platinum electrode, and an Ag/AgCl reference electrode. The potentiometric measurement indicates that human breast milk has the highest redox potential, while the commercial UHT milk has very low potential. Infant formulas also have high potential. The main advantage of electrochemical methods used to assess the total antioxidant activity of milk was that they directly monitored the electron-donating ability of the compounds and could be used for the quantitative analysis of the total antioxidants of different types of milk.