Light-induced oxidation in sliced Havarti cheese packaged in modified atmosphere

Sliced Havarti cheese, stored at 5 degrees C for up to 21 days in retail packages with an atmosphere of 25% CO2 and 75% N-2 with an initial 0.4% O-2, exposed to light (1000 1x) or protected against light, showed an increase in redness, no significant change in lightness and a tendency of decrease in yellowness measured as the u*, L* and b* tristimulus colour parameters, respectively. Light exposure decreased the riboflavin content significantly. The tendency of formation of free radicals in the cheese, determined in freeze-dried samples by ESR spectroscopy as an early event in lipid oxidation, decreased during the initial stages of storage to reach a minimum after four days, most rapidly in cheeses exposed to light. Whereas the lack of ability to resist lipid oxidation could not be detected in the peroxide value, sensory evaluation of odour and taste gave a clear indication of the role of light in promoting oxidation. Principal component analysis moreover showed a high correlation of the individual sensory characteristics. (C) 2000 Elsevier Science Ltd. All rights reserved.