Structural changes of gliadins during sourdough fermentation as a promissing approach to gluten-free diet

Abstract

Gluten intolerance, celiac disease, is an autoimmune disease caused by the ingestion of gluten proteins and the only treatment is the strict gluten-free diet which results in a mucosal recovery. At this point, the variety, availability and low price of gluten-free products on the market are of great importance. Sourdough is a traditional fermented semi-product that contains lactic acid bacteria (LAB). LAB are capable of metabolizing proteins and peptides with their proteolytic enzymes. It is predicted that gluten proteins are able to be hydrolyzed with the help of this proteolytic mechanisms and also by the wheat proteolytic enzymes. the help of this proteolytic mechanisms and also by the wheat proteolytic enzymes. gliadins involved in gluten intolerance during sourdough fermentation with selected LAB. First, sourdough fermentation with selected Lactobacillus strains was accomplished. As a control, dough with no inoculation and chemically acidified dough were prepared. During 48 h of fermentation, changes in pH, acidity, LAB concentration and free amino nitrogen content were investigated. SDS-PAGE, 2-D electrophoresis and RP-HPLC were applied to prolamins extracted from each sourdough sample taken at definite time intervals. The results showed that the inoculated LAB adapted to the dough environment and as they grew, a decrease in pH, and an increase in acidity and free amino nitrogen were observed. According to SDS-PAGE, 2-D electrophoresis and RP-HPLC results, some modifications in the protein patterns were observed in the inoculated doughs. The same alterations occurred in control and chemically acidified doughs, but not as fast as inoculated ones.