Heating inactivates the enzymatic activity and partially inactivates the allergenic activity of Asp o 2

Sensitization to various flours and flour additives in the baking industry has been known for some time. However, most studies refer to allergens in their native state.

The aim of our study was to find out how high temperatures during the baking process influence enzymatic and allergenic activities of the common flour additive alpha-amylase (Asp o 2), a relevant allergen for bakers derived from Aspergillus oryzae.

In order to assess the allergenicity of Asp o 2 during the baking process, four to 11 correspondingly sensitized bakers were investigated by Enzyme Allergo-Sorbent Test (EAST) with native Asp o 2 and Asp o 2 heated to 80, 90, 95, 99.8 or 200 degrees C. Furthermore, the enzymatic activity was assayed in simulated baking processes at the above mentioned temperatures.

Elevated temperatures resulted in a gradual loss of IgE antibodies' recognition of Asp o 2 in two commercially available enzyme products. The enzymatic activity decreased more rapidly. Heating the enzyme to 200 degrees C abolished both the enzymatic and the allergenic activity of the enzyme.

Based on these results, alpha-amylase in flour additives partially retains its allergenicity. This finding could be relevant for consumers.