Reduction of gluten-allergenic peptides by lactobacilli and pediococci isolated from sourdough

GEREZ, L.; ROLLÁN, G.; FONT DE VALDEZ, G

Tucumán

Simposio; II Simposio Internacional de Bacterias Lácticas; 2006

Centro de Referencia para Lactobacillus

During dough fermentation, lactic acid bacteria (LAB) are capable to hydrolyse wheat flour proteins into small peptides and amino acids, which act as bacterial growth enhancers and also as aroma compounds precursors. The LAB proteolytic activity would also contribute to a decrease in alfa gliadin-allergenic peptides. In previous studies, 13 strains [L. plantarum (4), L. reuteri (3), L. brevis (1), L. curvatus (1), P. pentosaceus (4)] were selected on the basis of gluten utilization. The aim of this study was to evaluate the activity of these strains on synthetic peptides, which have sequence similar to those present in gliadin fractions involved in allergy. The amino (AP), endo (EP), di (DP) and tri (TP) peptidases activities were determined in cell free extracts (CFE) using the following substrates: a) p-nitroaniline derivates (Leu-p-NA, Pro- p-NA, Glu- p-NA, Suphepha- p-NA, Gluphepha p-NA), b) di- and tri- peptides (Leu-Leu, Leu-Pro, Leu-Leu-Leu, Leu-Gly-Gly, Leu-Gly-Phe) y c) gliadin-derived synthetic peptides (31-43 and 33 mer). Proline is a predominant amino acid in gluten and unique due to its cyclic structure, which posse restrictions to proteolysis. All LAB strains -except for P.pentosaceus CRL 793- had activity AP on Pro- p-NA (0.9-6.1nmol/min.mg prot). About 50% of the strains tested hydrolysed Leu-Pro (2-7nmol/min mg prot). Significatively higher (P