Effect of modified atmosphere packaging and storage conditions on photooxidation of sliced Havarti cheese

The impact of different modified atmosphere packaging and storage conditions on photooxidation of sliced Havarti cheese during 168 It storage has been evaluated by color measurements (CIE L*,a*,b*), secondary oxidation product formation by solid-phase microextraction GC/MS, and open-end fluorescence spectrometry. For cheeses exposed to light and packaged with 0.6% residual oxygen, photooxidation, quantified by formation of 1-pentanol and I-hexanol, increased significantly during storage compared to cheeses packaged with only 0.01% residual oxygen (obtained by applying oxygen absorbers). Under the same conditions, increasing the headspace (approximately 1:1.5 and 1.5:1 product-to-headspace ratios) also led to increased light-induced oxidation. No effects of temperature (3 degreesC and 10 degreesC), light source (yellow light as opposed to standard fluorescent light) or light intensity (600 1x and 1200 1x) on photooxidation were noted. However, fluorescence and color measurements suggested a protective effect of yellow light, since riboflavin degradation and color fading were less pronounced in samples stored in yellow light than in standard fluorescent light. However, for real-life display conditions, photo-induced quality deterioration may be controlled only by the residual oxygen content, which should be lowered to less than 0.6%.