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United States Department of Agriculture

Agricultural Research Service

Title: Different processing methods alter the ability of allergens to sensitize.

Authors
item Maleki, Soheila
item Schmitt, David
item Koenig, Robbin
item Yamaki, Kohji -
item Champagne, Elaine
item Shinohara, K -

Submitted to: UJNR Food & Agricultural Panel Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 15, 2004
Publication Date: November 25, 2004
Citation: Maleki, S.J., Schmitt, D.A., Koenig, R.L., Yamaki, K. 2004. Different processing methods alter the ablity of allergens to sensitize. UJNR Food & Agricultural Panel Proceedings. 114-118.

Interpretive Summary: Our previous research has shown that certain processing methods, such as roasting, can increase the allergenic properties of the peanut allergens. To determine if these enhanced, in vitro, allergenic properties can influence the original development of peanut allergy, mice were sensitized with extracts from rice, soy, and raw, light roast, dark roast peanuts, and then skin tested. We found that mice sensitized with roasted peanuts had higher skin test reactivity than mice sensitized with raw peanuts, rice, or soy, indicating that roasted peanuts were the most likely to sensitize. Since one of the classic properties of food allergens is that they are resistant to digestive enzymes, and this has only been shown using purified allergens, we examined the digestibility of the major allergens, Ara h 1 and Ara h 2, within the context of raw and roasted peanuts as a possible explanation for enhanced sensitization capabilities of roasted peanuts. We found that Ara h 1 and 2 in roasted peanuts are much more resistant to digestion by trypsin, and in simulated gastric fluid (SGF) in raw peanut extracts. Several IgE-binding proteins and larger fragments of proteins survive digestion for over 18 hours in the roasted peanut extracts, versus the raw peanut extract. Also, these allergens are much more resistant to digestion within the context of other peanut proteins than in purified form. The surviving fragments bind to IgE, which indicates that they are absorbed into the bloodstream where they can cause mast cell degranulation and an immune response that leads to sensitization.

Technical Abstract: Our previous research has shown that certain processing methods, such as roasting, can increase the allergenic properties of the peanut allergens. To determine if these enhanced, in vitro, allergenic properties can influence the original development of peanut allergy, mice were sensitized with extracts from rice, soy, and raw, light roast, dark roast peanuts, and then skin tested. We found that mice sensitized with roasted peanuts had higher skin test reactivity than mice sensitized with raw peanuts, rice, or soy, indicating that roasted peanuts were the most likely to sensitize. Since one of the classic properties of food allergens is that they are resistant to digestive enzymes, and this has only been shown using purified allergens, we examined the digestibility of the major allergens, Ara h 1 and Ara h 2, within the context of raw and roasted peanuts as a possible explanation for enhanced sensitization capabilities of roasted peanuts. We found that Ara h 1 and 2 in roasted peanuts are much more resistant to digestion by trypsin and in simulated gastric fluid (SGF) in raw peanut extracts. Several IgE-binding proteins and larger fragments of proteins survive digestion for over 18 hours in the roasted peanut extracts, versus the raw peanut extract. Also, these allergens are much more resistant to digestion within the context of other peanut proteins than in purified form. The surviving fragments bind to IgE, which indicates that they are absorbed into the bloodstream where they can cause mast cell degranulation and an immune response that leads to sensitization.

Last Modified: 12/21/2014
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