Antioxidant capacity of human milk: effect of thermal conditions for the pasteurization

Aim: Pasteurization is the thermal treatment usually applied in milk banks to eliminate the risk of transmission of infectious agents. The aim of this study was to investigate the effect of heat processing upon the antioxidant properties of human milk. Methods: Milk samples collected from 31 healthy women were subjected to two different pasteurization techniques: Holder pasteurization (63°C for 30 min) and high pasteurization (75°C for 15 sec) and oxidative stress markers (glutathione, glutathione peroxidase activity, malondialdehyde and total antioxidant capacity) were determined in comparison to fresh milk. Results: Malondialdehyde concentration was the same in all samples, while there was a decrease in glutathione concentration and total antioxidant capacity in milk samples subjected to thermal processing versus fresh milk samples. However, the drop in these parameters was seen to be significantly greater when applying Holder pasteurization. Both thermal treatments induced considerable and similar loss of glutathione peroxidase activity. Conclusion: Thermal processing of human milk implies a decrease in its antioxidant properties but, when necessary, high pasteurization should be the election method in terms of milk oxidative status.