MOLECULAR ANALYSIS OF EFFECTS OF ENVIRONMENT ON WHEAT FLOUR QUALITY AND ALLERGENIC POTENTIAL
Location: Crop Improvement & Utilization Research
Title: The surface-associated proteins of wheat starch granules: suitability of wheat starch for celiac patients
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 29, 2008
Publication Date: October 7, 2008
Citation: Kasarda, D.D., Dupont, F.M., Vensel, W.H., Altenbach, S.B., Lopez, R., Tanaka, C.K., Hurkman II, W.J. 2008. The surface-associated proteins of wheat starch granules: suitability of wheat starch for celiac patients. Journal of Agricultural and Food Chemistry. 56:10292-10302.
Interpretive Summary: Celiac disease is an important condition in which an immune response to wheat gluten proteins in susceptible humans results in damage to the absorptive epithelium of the small intestine producing a malabsorption syndrome. Although wheat starch products are considered safe for celiac patients in some European countries, such products are avoided in the US because of a lack of knowledge of the degree of contamination of starches produced in the US or Canada. In this paper, we have analyzed commercial starches produced in the US or Canada (NA) for gluten proteins, and compared these starches with a European starch often used for products for celiac patients. We showed that one NA starch was extremely low in gluten proteins and another, although higher, was within allowed limits by the Codex Alementarius for wheat starch products intended for use by celiac patients. This work moves toward a possible addition of wheat starch products to the current range of products available to people on a gluten-free diet.
Wheat starch is used to make baked products for celiac patients in several European countries, but is avoided in the US because of uncertainty about the amounts of associated grain storage (gluten) proteins. People with celiac disease (CD) must avoid wheat, rye and barley proteins and products that contain them. These proteins are capable of initiating damage to the absorptive lining of the small intestine in CD patients, apparently as a consequence of undesirable interactions with the innate and adaptive immune systems. In this study, starch surface-associated proteins were extracted from four commercial wheat starches, fractionated by HPLC and gel electrophoresis, and identified by MS/MS analysis. More than 150 proteins were identified, many of which (for example, histones, purothionins, and glutenins) had not been recognized previously as starch-associated. The commercial starches were analyzed by the R-5 ELISA method to estimate the amount of harmful gluten protein present. One of these starches had a gluten content of 7 ppm and falls within the range proposed as a new Codex Alimentarius Standard for naturally gluten-free foods (max. 20 ppm).