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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: Allergenicity of Peanut Proteins is Retained Following Enzymatic Hydrolysis

Authors
item Guo, R -
item Shi, X -
item White, Brittany
item Sanders, Timothy
item Burks, A -
item Davis, Jack
item Kulis, M -

Submitted to: American Academy of Allergy Asthma and Immunology
Publication Type: Abstract Only
Publication Acceptance Date: January 30, 2012
Publication Date: N/A

Technical Abstract: Rationale: Hydrolysis of peanut proteins by food-grade enzymes may reduce allergenicity and could lead to safer forms of immunotherapy. Methods: Light roasted peanut flour extracts were digested with pepsin (37°C, pH 2), Alcalase (60°C pH 8), or Flavourzyme (50°C, pH 7) up to 1 hr, or sequentially with Alcalase and Flavourzyme for 30 min each. Hydrolysates were analyzed by size-exclusion chromatography (SEC), SDS-PAGE, and Western blotting with human peanut-allergic plasma. Basophil degranulation assays were conducted on whole blood from peanut-allergic individuals and monitored by CD63 up-regulation, while T cell proliferation was investigated by a CFSE-incorporation assay. Results: Hydrolysis with pepsin, Alcalase or Flavourzyme resulted in distinct SDS-PAGE and SEC patterns and the degree of hydrolysis (DH) after 1 hr was approximately 15, 22 and 27%, respectively. DH for sequential hydrolysates was approximately 37%. All peptides were less than ~ 20 kDa and proportions of lower MW peptides increased with increasing DH. Western blotting demonstrated that IgE-binding fragments existed for each of the hydrolysates although the sizes were much smaller than the non-hydrolyzed controls. No appreciable effect was seen with any of the 3 hydrolysates in the basophil assays (n=5 subjects) compared to non-hydrolyzed controls. T cell proliferation assays (n=5 subjects) indicated that hydrolysates retained ~50% of the CD4+ T cell stimulation effect as compared to non-hydrolyzed controls. Allergenicity data for sequential hydrolysates and fractions collected from SEC will also be presented. Conclusions: Hydrolysis of peanut proteins yields low MW peptides that retain IgE cross-linking properties as evidenced by basophil degranulation assays.

Last Modified: 4/16/2014
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