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United States Department of Agriculture

Agricultural Research Service

Research Project: Improvement & Maintenance of Flavor & Shelf-Life, Functional Characteristics & Biochem/Bioactive Process, & Use of Genetic/Genomic Resource

Location: Market Quality and Handling Research

Title: Allergenic Properties of Enzymatically Hydrolyzed Peanut Flour Extracts

Authors
item Shi, Xiaolei -
item Guo, Rishu -
item White, Brittany
item Sanders, Timothy
item Davis, Jack
item Burks, A -
item Kulis, Michael -

Submitted to: International Archives of Allergy and Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 30, 2012
Publication Date: February 22, 2013
Repository URL: http://DOI:10.1159/000351920
Citation: Shi, X., Guo, R., White, B.L., Sanders, T.H., Davis, J.P., Burks, A.W., Kulis, M. 2013. Allergenic Properties of Enzymatically Hydrolyzed Peanut Flour Extracts. International Archives of Allergy and Immunology. 162:25-32.

Interpretive Summary: Peanut allergy is considered one of the most severe food allergies due to its life-threatening nature and persistency. Peanut flour, which is a high protein, low oil, powdered material prepared from roasted peanut seed, is used as food ingredient and is the active ingredient in peanut oral immunotherapy (OIT) trials. Although OIT has shown promise for desensitizing peanut allergic subjects, the risk of an adverse immune response exists. This research evaluates enzymatic hydrolysis using Alcalase, Flavourzyme, and pepsin as a processing strategy to generate peanut flour hydrolysates with reduced IgE binding and improved OIT potential through modulation of immunogenic properties. In this short communication, peanut IgE reactivity was evaluated by both Western blotting and basophil activation tests, which is a more robust and physiologically relevant functional test that measures IgE cross-linking capacity. Western blotting revealed the hydrolysates retained minimal IgE binding reactivity and these novel IgE reactive peptides were primarily Ara h 2 fragments regardless of protease tested. However, basophil activation tests revealed that all hydrolysates retained IgE cross-linking capacity suggesting such hydrolysates are not hypoallergenic and may not be suitable for OIT. Reasons for the discrepancies between results from Western blotting and basophil activation tests are also discussed. The findings of this study contribute broadly to peanut allergenicity research and more specifically to research aiming to identify safer ingredients for OIT.

Technical Abstract: Peanut flour is a high protein, low oil, powdered material prepared from roasted 21 peanut seed. In addition to being a well-established food ingredient, peanut flour is also the 22 active ingredient in peanut oral immunotherapy trials. Enzymatic hydrolysis was evaluated as a 23 processing strategy to generate hydrolysates from peanut flour with reduced allergenicity. 24 Methods: Soluble fractions of 10 % (w/v) light roasted peanut flour dispersions were 25 hydrolyzed with the following proteases: Alcalase (pH 8.0, 60 °C), pepsin (pH 2.0, 37 °C), and 26 Flavourzyme (pH 7.0, 50 °C) for 60 min. Western blotting and basophil activation tests were 27 used to examine IgE reactivity. Results: Western blotting experiments revealed the hydrolysates 28 retained minimal IgE binding reactivity and these novel IgE reactive peptides were primarily Ara 29 h 2 fragments regardless of protease tested. Basophil activation tests revealed that all 30 hydrolysates were comparable (p > 0.05) to unhydrolyzed controls in IgE cross-linking capacity. 31 Conclusions: These results indicate that hydrolysis of peanut flour reduced IgE binding capacity, 32 but retained IgE cross-linking capacity during hydrolysis suggesting such hydrolysates are not 33 hypoallergenic.

Last Modified: 10/1/2014
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