Effect of the light intensity and packaging materials on the photooxidation and volatile compounds in milk

Photooxidation occurs in milk during storage, possibly leading to loss of nutritional values and unacceptable flavour. The photooxidation of extended shelf-life (ESL) milk was evaluated by monitoring the concentrations of riboflavin and dissolved oxygen and volatile compounds, and peroxide values, during storage at 8 degrees C for 30 d. The effects of different packaging strategies and light intensity on photooxidation rate were evaluated. Poly-ethylene terephthalate (PET) packaging pigmented with 8% (w/w) UV light-absorbing additive reduced the photooxidation in ESL milk at light intensities ranging from 1000 to 4000 lux during storage. PET with 2% (w/w) oxygen scavenger did not provide sufficient protection for the ESL milk to photooxidation during the storage under illumination of 3500-4000 lux. This study provides insights into achieving better strategies for packaging of ESL milk with improved quality and longer shelf-life.