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

Background: 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.

Objective: 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.

Methods: 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.

Results: 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.

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