Comparative studies on the generation of acrolein as well as of aroma-active compounds during deep-frying with different edible vegetable fats and oils

It is well-known that high temperature cooking of food can lead to the generation of several decomposition compounds, which may either provide desirable qualities, like taste and flavor, or undesirable properties showing adverse effects on human health. Therefore, the present study investigated the influence of different oils on the generation of desirable aroma-active compounds and the undesirable food-borne toxicant acrolein during frying. For this purpose, six edible fats and oils varying in their fatty acid composition were used for deep-frying of thin potato slices. After the frying process, first, the key aroma compounds of the chips were quantified by means of stable isotope dilution assays. Secondly, acrolein was quantified in chips as well as in the frying medium. For this purpose, two quantitation methods for acrolein using stable isotopically labeled [¹³C₃]-acrolein as internal standard were newly developed. The results clearly showed that the use of a frying medium mainly consisting of mono-unsaturated or saturated fatty acids led to significantly lower amounts of (E,E)-2,4-decadienal and (E,Z)-2,4-decadienal in chips. In contrast, acrolein generation in chips seemed not to be affected by the type of frying medium. However, significantly elevated acrolein concentrations were generated in those oils containing higher amounts of linolenic acid (e.g., rapeseed or linseed oil).