The toxic aldehyde, 4-hydroxy-2-trans-nonenal (HNE) formation in natural and imitation mozzarella cheeses: Heat treatment effects

The formation of 4-hydroxy-2-trans-nonenal (HNE), a toxic aldehyde formation, was investigated in heat treated imitation Mozzarella cheeses which are made with vegetable oils and in natural Mozzarella cheeses which contain dairy fats. The cheeses were heat treated at 204 °C for 30 and 60 min, and at 232 °C for 15 and 30 min. The HNE formations were much higher in imitation cheeses than in natural cheeses due to both heat treatments. Average HNE concentrations in imitation cheeses, after 30 min of heat treatment at 204 °C, were 110.3 ng HNE/g cheese and it increased to 877.1 ng HNE/g cheese when the temperature was raised to 232 °C. In natural cheeses, the average HNE concentration was much lower only 13.4 ng HNE/g cheese after 204 °C heat treatment for 30 min and it increased only to 182.8 ng HNE/g cheese using 232 °C. Since imitation cheeses are made with vegetable oils which contain much higher levels of linoleic acid, a precursor for HNE, than dairy fat, it is not surprising that heat-induced lipid peroxidation results in increased HNE formation in imitations cheeses compared to dairy fat containing cheeses, which are low in linoleic acid.