ARS | Publication request: Enzymatic Hydrolysis of Peanut Flour Produces Bioactive Peptides with Reduced Allergenicity

Submitted to: Institute of Food Technology
Publication Type: Abstract Only
Publication Acceptance Date: June 6, 2012
Publication Date: N/A

Technical Abstract: Peanut allergy is one of the most severe food allergies due to its life-threatening nature and persistency. Current immunotherapy methods, though effective, are often accompanied by allergic side-effects. Enzymatic hydrolysis of peanut flour has the potential to produce bioactive peptides with improved immunotherapy properties. To investigate this potential, soluble fractions of 10% (w/w) light roasted peanut flour dispersions were hydrolyzed with Alcalase (pH 8.0, 60°C), pepsin (pH 2.0, 37°C), Flavourzyme (pH 7.0, 50°C), or sequentially with Alcalase and Flavourzyme. Trinitrobenzenesulfonic (TNBS) acid method and SDS-PAGE were used to determine degree of hydrolysis (DH) and visualize peptide formation, respectively. Bioactivity was evaluated by determining angiotensin-converting enzyme (ACE) inhibition and Oxygen Radical Absorbance Capacity (ORAC). Immunoreactivity was evaluated by Western blotting, T cell proliferation, and basophil degranulation. DH of the hydrolysates ranged from 14.89 % to 37.37%. ACE inhibition plateaued after 30 min hydrolysis, and 2 to 3-fold increases in ORAC values were observed for all 60-min hydrolysates compared with non-hydrolyzed control. The SDS-PAGE band intensity of major peanut allergens, Ara h 1 and Ara h 3/4 decreased and a series of smaller MW (3-22 kDa) subunits were produced. Alcalase hydrolysates displayed minimal IgE binding, whereas Flavourzyme and pepsin hydrolysates displayed very clear IgE binding in the region of 0-28 kDa. T cell proliferation assays (n=5 subjects) indicated that hydrolysates retained ~50% of the T helper cells stimulation compared to non-hydrolyzed controls. Data for individual hydrolysates was comparable to unhydrolyzed controls in the basophil assay (n=5 subjects). Immunoreactivity data of sequential hydrolysates and peptide fractions will also be presented. Results indicate that hydrolysis of peanut flour produces low MW bioactive peptides with reduced allergenicity, which may potentially be used as a safer means of immunotherapy.