The behavior of hypersensitivity-causing proteins during food processing

Friday, August 26, 2016

Authors: Kitti Török, Eszter Schall, Lívia Hajas, Zsuzsanna Bugyi, Sándor Tömösközi

1. Summary


Since the components causing hypersensitivity reactions (allergies, celiac disease) are usually proteins, therefore, learning about their potential changes is important from the food safety point of view. If the proteins undergo various structural modifications during processing, their determination in foods could be problematic. Nevertheless, the fact that these altered proteins cannot be detected using analytical methods does not necessarily mean that they cannot cause adverse reactions in the human body. Answering the questions that arise in connection with this topic requires the cooperation of patients, clinicians and analysts as well.
Foods intended for final consumption undergo several processing steps while going from raw material to final product. Each process that alters the structure of proteins is also expected to have an effect on their binding to antibodies. Food processing procedures cause a number of physical, chemical and biochemical changes that can affect the allergenic properties of a protein. Depending on the properties of the protein, the type, length and intensity of the processing operation, or the matrix, the allergenic effect of a protein can be increased, decreased, or left unchanged by processing.
ELISA tests, which are currently used in routine methods, employ various antibodies, so the epitopes targeted in the immune responses can also be different. The various epitopes can undergo different modifications during food processing, therefore, their affinity to the antibody can also change, which can affect the results provided by the method. This phenomenon calls attention to the fact that the accuracy of commercially available methods is questionable, and so both the improvement and harmonization of immunoanalytical methods is necessary.


2. Introduction


Hypersensitivity reactions to foods present a severe food safety problem. For the majority of non-toxic reactions, eight food ingredients are responsible: gluten, raw materials made from crustaceans, eggs, fish, peanuts, soy, milk and products made of nuts. In addition to these, six other components that cause hypersensitivity reactions (celery, mustard, sesame seeds, lupine, mollusks, sulfur dioxide) also have to be indicated on food packaging in the EU [1]. With the exception of sulfur dioxide, disorders are caused by the protein components of the given food. It can be said about each food ingredient that they have very diverse protein compositions, and they contain a number of proteins in which the hypersensitivity reaction triggering special amino acid sequences, the so-called epitopes can be found.

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