Oxidative stability of cream cheese stored in thermoformed trays as affected by packaging material, drawing depth and light

The oxidative stability of cream cheese stored in thermoformed trays made of amorphous polyethylene terephtalate (A-PET)/polyethylene (PE), polystyrene (PS)/Ethylene-vinylalcohol copolymer (EVOH)/PE and Polypropylene (PP)/PE with different depth (25, 50 and 70 mm) and colour (black, white and transparent) was studied by sensory evaluation and gas chromatographic analysis of volatile compounds. The polymer combination had an important effect on sensory scores of both sunlight and acidulous flavour in cream cheese stored in the dark for 2, 4 and 6 months. Cream cheese stored in trays made of A-PET/PE had higher acidulous flavour and lower content of hexanal and 2-nonanone. Only small differences were observed between PS/EVOH/PE and PP/PE despite the great diversity of oxygen transmission rates. The drawing depth of the packages had no significant effect on oxidative stability of cream cheese, irrespective of storage in the dark or under illumination. The colour of the examined packaging material had a pronounced effect on photoxidative changes in cream cheese.