Oxidation-reduction potential in the milk from mothers of preterm infants

Abstract

Background and Aims Health benefits of mother’s milk depend on the level of the total antioxidant capacity (TAC). In mother’s milk, the TAC should refer to the sum of activities derived from active enzymatic antioxidant systems (e.g. superoxide dismutase, catalase, glutathione peroxidase etc.), nonenzymatic antioxidants, such as vitamins C and E, and the presence of other bioactive factors (e.g. lactoferrin, uric acid etc.). Measuring oxidation-reduction potential (ORP) using RedoxSYS Analyzer may be an alternative to classic methods of measuring TAC. We compared the results of OPR and ascorbic acid content in milk from mothers of preterm infants. Method Milk was obtained from ten mothers of preterm infants (gestational age 28-36 weeks; birth weight 900-2,470 g). Milk samples were obtained within the first 4 days after delivery (colostrum), from day 4 to two weeks (transient), and 6 weeks and later (mature milk). Static oxidation−reduction potential (ORP) of milk from mothers of preterm infants was measured using RedoxSYS Analyzer (Luoxis Diagnostics, Englewood, CO). Ascorbic acid content was measured in milk samples and results were expressed as mg/l. Procedure suggested by the manufacturer was used (Reflect quant® ascorbic acid test for reflectometerRQflex®, Merck KGaA, Germany, 2006). Results There are similarities in the results of OPR and vitamin C concentration in colostrum, transient and mature milk from mothers of preterm infants. Conclusion Vitamin C concentration influenced the value of OPR most.