Effect of different physical treatments on antioxidant activity of jenny milk

The shelf life of food can be extended by employing several physical treatments. Among them, pasteurization and condensation are widely adopted for prolonging the shelf-life of milk by reducing the microbial load. However, these treatmens could affect the antioxidant activity of the product. The aim of the present study was to investigate the effect of pasteurization and condensation on the Total Antioxidant Capacity (TAC) of raw and pasteurised jenny milk. Using 2,2’-azinobis (3-ethylbenzthiazoline-6-acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. TAC was also measured after condensation at 40 and at 20% of the initial volume. ABTS assay was found to be more accurate and reproducible than DPPH. Pasteurisation reduced significantly (P<0.05) the total antioxidant capacity from 84.15to 82.09% (ABTS test). The TAC decreased with the increase of condensation in raw and pasteurised milk. Overall, the TAC was reduced by only 3 and 4%, in pasteurised and in raw milk, respectively (ABTS test). Therefore, both pasteurization and condensation are recommended as physical treatments to prolong the shelf-life of jenny milk