Controlling Oxidation in Cheese

TJELE, DenmarkLight-induced oxidation is a frequently occurring problem in cheese products because it is often stored in transparent packages. This results in flavor defects in regular and lowfat cheeses and rejected products, so elucidating the causes and solutions would prove valuable to the dairy industry.

The storage conditions cheese is subjected to affects its oxidative stability. Both modified atmosphere and light exposure influence the formation of undesirable oxidation products and off flavors.

To examine the cause of photo-oxidation in cheese, Danish researchers at Aarhus University teamed up with scientists from Arla Foods to investigate the effect of fat content and availability of oxygen on light-induced oxidation in cheese. Theorizing that high fat content would increase lipid oxidation products during light exposure, while low fat content might increase the oxidation of proteins, they looked at two different model cheeses with 5.4% and 18% fat, packed in air and in vacuum.

They found that at lipid and protein oxidation in complex matrices such as cheese is a complicated process. Protein oxidation correlated to the fat content of the cheeses, and interaction between the lipid radicals and proteins seemed to influence the generation of dityrosine. The amount of protein oxidation compounds (dityrosine and dimethyl disulphide (DMDS)) and lipid oxidation products (lipid hydroperoxides, pentanal, hexanal and heptanal) were significantly reduced in vacuum-packed cheeses compared to those cheeses packed in air.