Abstract
BackgroundAcid hydrolyzed wheat proteins (HWPs) are used in the food and cosmetic industry as emulsifiers. Cases of severe food allergic reactions caused by HWPs have been reported. Recent data suggest that these reactions are caused by HWPs produced by acid hydrolysis.ObjectivesTo examine the sensitizing capacity of gluten proteins per se when altered by acid or enzymatic hydrolysis relative to unmodified gluten in rats naïve to gluten.MethodsHigh IgE-responder Brown Norway (BN) rats bred on a gluten-free diet were sensitized without the use of adjuvant to three different gluten products (unmodified, acid hydrolyzed and enzymatic hydrolyzed). Rats were sensitized by intraperitoneal (i.p.) immunization three times with 200 µg gluten protein/rat or by oral dosing for 35 days with 0.2, 2 or 20 mg gluten protein/rat/day. Sera were analyzed for specific IgG and IgE and IgG-binding capacity by ELISA. IgE functionality was measured by rat basophilic leukemia (RBL) assay.ResultsRegardless of the route of dosing, all products had sensitizing capacity. When sensitized i.p., all three gluten products induced a strong IgG1 response in all animals. Acid hydrolyzed gluten induced the highest level of specific IgE but with a low functionality. Orally all three gluten products induced specific IgG1 and IgE but with different dose-response relations. Sensitizing rats i.p. or orally with unmodified or enzymatic hydrolyzed gluten induced specific IgG1 responses with similar binding capacity which was different from that of acid hydrolyzed gluten indicating that acid hydrolysis of gluten proteins induces formation of ‘new’ epitopes.ConclusionsIn rats not tolerant to gluten acid hydrolysis of gluten enhances the sensitizing capacity by the i.p. but not by the oral route. In addition, acid hydrolysis induces formation of new epitopes. This is in contrast to the enzymatic hydrolyzed gluten having an epitope pattern similar to unmodified gluten.
Highlights
Gluten proteins are wheat storage proteins, constituting about 10% of wheat, and give wheat dough functional properties such as water absorption capacity, viscosity and elasticity, which contribute to the unique baking properties [1,2,3]
Sensitizing rats i.p. or orally with unmodified or enzymatic hydrolyzed gluten induced specific IgG1 responses with similar binding capacity which was different from that of acid hydrolyzed gluten indicating that acid hydrolysis of gluten proteins induces formation of ‘new’ epitopes
Acid hydrolysis induces formation of new epitopes. This is in contrast to the enzymatic hydrolyzed gluten having an epitope pattern similar to unmodified gluten
Summary
Gluten proteins are wheat storage proteins, constituting about 10% of wheat, and give wheat dough functional properties such as water absorption capacity, viscosity and elasticity, which contribute to the unique baking properties [1,2,3]. Oligomers and polymers are linked by disul-phide bonds between the S-containing amino acid cysteine, which make up approximately 2% of gluten. Based on their physical characteristics, gluten proteins can be divided into gliadins and glutenins. Gliadins and glutenins consist mainly of glutamine, proline and the essential amino acid phenylalanine [3,4]. Another unique feature about gluten proteins is their structures, which are dynamic, comprise interchanging conformations and do not unfold when exposed to heating like most other proteins [5]. Recent data suggest that these reactions are caused by HWPs produced by acid hydrolysis
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call