Author
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MALEKI, SOHEILA - 6435-56-00 |
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Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only Publication Acceptance Date: 8/1/2003 Publication Date: 10/1/2003 Citation: Maleki, S.J. 2003. The effects of processing on the structure, function and allergenic properties of peanut proteins. American Chemical Society Abstracts.83. Interpretive Summary: Technical Abstract: Little is known about the reasons why certain foods are allergenic and others are not. Some classic characteristics associated with food allergens are resistance to digestion and heat, stimulation of T cell proliferation, IgE binding and abundance in food. Certain enzymatic functions have also been associated with allergenicity of proteins. However, not much is known about what happens to the allergenicity of food products after processing. Here the consequences of roasting on the structural, functional immunological and allergenic properties of peanut proteins were examined. Following roasting, Ara h 1, one of the major peanut allergens, was shown to form irreversible trimers that are extremely resistant to digestion and bind higher levels of IgE than Ar h 1 from raw peanuts. The sequence of a second major peanut allergens, Ara h 2 was found to be homologous to trypsin/alph-amylase inhibitors. An enzymatic assay was used to show that Ara h 2 functions as a trypsin inhibitor. Most significantly, while the secondary structure remained unaltered, Ara h 2, purified from roasted peanuts was several fold more active as a trypsin inhibitor and bound higher levels of IgE than the Ara h 2 purified from raw peanuts. In order to assess the effect of these alterations in peanut proteins in vivo, mouse sensitization experiments were performed. We found that mice were more likely to be sensitized when treated with roasted peanuts than with raw peanuts. Our findings suggested that the structural and functional changes due to food processing contribute to increased allergenic properties of peanut proteins and may indeed enhance the possibility of becoming sensitized to peanuts. |
