The formation of significant levels of the suspected carcinogen acrylamide in carbohydraterich
foods subjected to intense heating (e.g. baking and frying) has been widely reported. Although it has been demonstrated that acrylamide is formed from the reaction between
free asparagine and intermediates of the Maillard reaction, the mechanisms at the basis of
the development of this substance are still not fully understood. Results have shown that the
kinetics of acrylamide formation are affected both by intrinsic factors of the food product,
such as reducing sugar and amino acid concentration, chemical composition, water content,
pH, physical state, etc., and process parameters (heating time and temperature).
Due to the complexity of influencing factors, up today it was difficult to draw up guidelines to
reduce acrylamide formation in foods. From a technological standpoint, the preliminary and
general suggestions are relevant to the adoption of thermal treatments other than frying or
prolonged cooking, which however are responsible for a decrease in the food sensorial
acceptability.
Radiofrequency heating is a promising technology for food applications, characterised by
rapid and uniform heat distribution, large penetration depth and low energy consumption.
It is generally applied as a post-baking operation to rapidly reduce the residual moisture of
bakery products from about 6% to 3%. Although the acrylamide levels in baked products
(breads, cakes, cookies, etc.) greatly vary with formulation and processing conditions
adopted, the amounts reported are quite high, generally of the order of 200-500 ppb.
The aim of the present study was to investigate the effects of radiofrequency heating on
acrylamide formation in bakery products. Leavened cakes were obtained from a commercial
ready-to-cook formulation. Cooking was carried out by using both conventional and
radiofrequency (RF) heating. Products having different moisture levels were analysed for
acrylamide content and colour properties Results showed that acrylamide formation was
affected by the mechanism of heat transfer, i.e. conduction or dielectric heating.
