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Identification of IgE-binding proteins in soy lecithin
1Department of Food Science and Technology, University of Nebraska, Lincoln, NE 68583-0919, USA.
International Archives of Allergy and Immunology
|December 26, 2001
Summary
Soy lecithin contains hidden allergens, including newly identified proteins, which may trigger allergic reactions in sensitive individuals. This finding is crucial for those with soy allergies consuming lecithin products.
Area of Science:
- Food science and immunology
- Allergen characterization
- Protein analysis
Background:
- Soy lecithin, a common food emulsifier, contains trace amounts of IgE-binding proteins.
- Clinical reports suggest a link between soy lecithin consumption and allergic reactions.
- Understanding these proteins is vital for managing food allergies.
Purpose of the Study:
- To identify and characterize the specific IgE-binding proteins present in soy lecithin.
- To assess the potential of soy lecithin as a source of hidden allergens.
Main Methods:
- Proteins were isolated from soy lecithin using solvent extraction.
- Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) separated proteins.
- Immunoblotting with soy-sensitive sera identified IgE-binding proteins, followed by N-terminal sequencing.
Main Results:
- Protein levels in commercial soy lecithin varied from 100 to 1,400 ppm.
- SDS-PAGE revealed consistent protein patterns across samples.
- IgE binding was observed at 7, 12, 20, 39, and 57 kD, with the 12-kD band identified as methionine-rich protein (MRP) and 2S albumin, the 20-kD band as Kunitz trypsin inhibitor, and the 39-kD band as an unknown soy protein.
Conclusions:
- Soy lecithin contains multiple IgE-binding proteins, acting as potential hidden allergens.
- Methionine-rich protein (MRP) and a 39-kD protein are newly identified IgE-binding proteins in soy lecithin.
- Soy-allergic individuals, especially those using lecithin as a supplement, should be aware of these potential allergens.