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United States Department of Agriculture

Agricultural Research Service

Research Project: Primary and Secondary Prevention of Peanut and Tree Nut Allergy

Location: Food Processing and Sensory Quality Research

Title: Allergenic properties and differential response of walnut subjected to processing treatments

Authors
item Cabanills, Beatriz -
item Maleki, Soheila
item Rodriguez, Julia -
item Cheng, Hsiaopo
item Teuber, Suzanne -
item Wallowitz, Mikhael -
item Muzquiz, Mercedes -
item Pedrosa, Mercedes -
item Burbano, Carme -
item Crespo, Jesus -

Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 12, 2014
Publication Date: March 16, 2014
Citation: Cabanills, B., Maleki, S.J., Rodriguez, J., Cheng, H., Teuber, S.S., Wallowitz, M.L., Muzquiz, M., Pedrosa, M.M., Burbano, C., Crespo, J.F. 2014. Allergenic properties and differential response of walnut subjected to processing treatments. Food Chemistry. 157:141-147.

Interpretive Summary: Walnut is one of the most frequently involved foods in anaphylactic reactions. We investigated changes in walnut allergenicity after physical treatments and physiologically relevant assays. Changes in the allergenicity of walnut subjected to high pressure and thermal/pressure treatments were evaluated by means of specific antibodies raised against the major walnut allergen Jug r 4. The allergenic properties of treated walnut samples were evaluated by means of a rat cell line treated with sera from walnut allergic patients, and by skin prick testing on walnut allergic individuals. Susceptibility to digestion was evaluated with gut enzymes. The results showed that walnut subjected to pressure and heat treatment was able to diminish allergenic properties more efficiently than only high pressure treated walnut. Immunoblot confirmed these results; moreover, higher susceptibility to physiologically digestion of pressure treated walnut proteins was observed. We conclude that pressure and heat treatment decreased allergenic properties in vitro more efficiently than high pressure treatments without heat and also largely diminished allergenic capacity of walnut. The use of processed walnut with decreased immunoglobulin E (IgE) antibody binding capacity could be an interesting strategy for walnut tolerance induction.

Technical Abstract: Walnut is one of the most frequently involved foods in anaphylactic reactions. We investigated changes in walnut allergenicity after physical treatments by in vitro techniques and physiologically relevant assays. Changes in the allergenicity of walnut subjected to high pressure and thermal/pressure treatments were evaluated by by means of specific antibodies raised against the major walnut allergen Jug r 4. The allergenic properties of treated walnut samples were evaluated by means of a rat basophil leukaemia cell line sensitized with sera from walnut allergic patients, and by skin prick testing on walnut allergic individuals. Susceptibility to digestion was evaluated using gastric and duodenal enzymes. The results showed that walnut subjected to pressure treatment at 256 kPa, 138 ºC, was able to diminish allergenic properties more efficiently than high pressure treated walnut. Immunoblot confirmed these results; moreover, higher susceptibility to physiologically digestion of pressure treated walnut proteins was observed. We conclude that pressure treatment at 256 kPa, 138 ºC decreased allergenic properties in vitro more efficiently than high pressure treatments without heat and also largely diminished allergenic capacity of walnut. The use of processed walnut with decreased IgE binding capacity could be an interesting strategy for walnut tolerance induction.

Last Modified: 10/26/2014
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