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United States Department of Agriculture

Agricultural Research Service

Research Project: REDUCING THE ALLERGENIC PROPERTIES OF PEANUTS

Location: Food Processing and Sensory Quality Research

Title: Processing effects on peanut allergens.

Authors
item Maleki, Soheila
item Nesbit, Jacqueline
item Dyer, Scott -
item Cheng, Hsiaopo

Submitted to: United States Japan Natural Resources Protein Panel
Publication Type: Proceedings
Publication Acceptance Date: September 10, 2009
Publication Date: October 2, 2009
Citation: Maleki, S.J., Nesbit, J.B. 2009. Processing effects on peanut allergens. United States Japan Natural Resources Protein Panel. 1-3.

Interpretive Summary: In the majority of patients, roasted peanuts resulted in a higher skin prick test (SPT). Purified peanut allergens, Ara h 1, Ara h 2, and Ara h 3 from roasted peanut, binds higher allergen-specific immunoglobulin E (IgE) antibody levels than from raw peanuts. To determine if there are any structural changes, and if these changes contribute to increased IgE binding by the proteins purified from roasted peanuts; we assessed the changes in the structure of each allergen purified from raw, light roast, and dark roast peanut, and compared the differences in IgE binding to these allergens. Ara h 1, 2, and 3 were purified from raw (R), light roast (LR), and dark roast (DR) peanuts. The IgE binding to each of these proteins was compared using sera from peanut allergic and non-allergic patients using immunoblot analysis. Circular dichroism (CD) spectroscopy was used to monitor the structural changes. While the structure of the allergens did not show large changes in allergens purified following various roasting processes, the IgE binding to the roasted samples increased significantly with time of roasting; therefore, we believe that the chemical modifications incurred by roasting are more important for IgE binding than processing induced structural changes. Understanding the differences in IgE binding to various processed forms of foods by allergic versus sensitized patient sera may be useful in development of more specific diagnostic tools, and potentially processes that can result in reduced allergenicity of a food.

Technical Abstract: In the majority of patients, roasted peanuts resulted in a higher skin prick test (SPT). Purified Ara h 1, Ara h 2, and Ara h 3 from roasted peanut binds higher IgE levels than from raw peanuts. To determine if there are any structural changes; and if these changes contribute to increased IgE binding by the proteins purified from roasted peanuts, we assessed the secondary structure of each allergen purified from raw, light roast, and dark roast peanut, and compared the differences in IgE binding to these allergens. Ara h 1, 2, and 3 were purified from raw (R), light roast (LR), and dark roast (DR) peanuts. The IgE binding to each of these proteins was compared using sera from peanut allergic and sensitized, but tolerant patients, using immunoblot analysis. Circular dichroism (CD) was used to monitor the structural changes. While the structure of the allergens did not show large changes when purified following various roasting processes, the IgE binding to the roasted samples increased significantly with time of roasting. The chemical modifications incurred by roasting are more important for IgE binding than processing induced structural changes. Understanding the differences in IgE binding to various processed forms of foods by allergic versus sensitized patient sera may be useful in development of more specific diagnostic tools, and potentially processes that can result in reduced allergenicity of a food.

Last Modified: 9/1/2014
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