Release of antioxidants from poly(lactide-co-glycolide) films into dry milk products and food simulating liquids

Poly(lactide-co-glycolide) (PLGA) (50:50) films loaded with antioxidants, such as 2%α-tocopherol, or a combination of 1% butylated hydroxytoluene (BHT) and 1% butylated hydroxyanisole (BHA), were used in an antioxidant release study in water and oil at 4 and 25 °C, and to evaluate the stability of dry whole milk and dry buttermilk in the presence and absence of light. BHT was the only antioxidant that was released through diffusion and hydrolytic degradation of the polymer, when stored in water at room temperature for 8 weeks. As expected, polymer degradation did not take place when antioxidant-loaded films were stored in oil, whole milk powder (3.01% moisture) and buttermilk powder (4.60% moisture). However, α-tocopherol, BHA and BHT were released through diffusion from 0 to 21.9, 0 to 60.0 and 0 to 192.0-mg kg^-1 milk fat, respectively, in whole milk powder after 4 weeks of storage at 25 °C. Pentanal, and not heptanal or hexanal, was significantly decreased when buttermilk powders were packaged in contact with BHA/BHT-loaded PLGA films.