Pediococcus as starter cultures for sourdough fermentation: Technological and functional properties

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

Bari, Italia

Simposio; 3rd International Symposium on Sourdough; 2006

Pediococcus as starter cultures for sourdough fermentation: Technological and functional properties Gerez, C. L.1, Rollán, G.1, Font de Valdez, G.1, 2 1Centro de Referencia para Lactobacilos (CERELA-CONICET) Chacabuco 145. Tucumán, Argentina. 2Facultad de Bioquímica, Química y Farmacia. Universidad Nacional de Tucumán. Tucumán, Argentina.   The proteolytic system of lactic acid bacteria (LAB) releases amino acids (aa) and small peptides during sourdough fermentation, which promote the growth and metabolic activities of the microorganisms. Moreover, it may contribute to reduce the content of allergenic peptides that are present in gluten. The aim of the present study was to evaluate pediococci strains isolated from argentinean homemade sourdough as a source of protelytic enzymes in a culture medium with gluten as sole nitrogen source (GBM). Out of twenty strains, only P. pentosaceus CRL 761, CRL 792, CRL 793 and CRL 797 were able to hydrolyze gluten and grow in GBM, the strain CRL 797 being the most active. New peptides of 7 and 16 kDa were detected in P. pentosaceus CRL 797 and P. pentosaceus CRL 761 cultures while the concentrations of ornithine (flavour precursor of bread crust) and lysine (limiting essential aa in wheat flour) increased by 70 and 150% in P. pentosaceus CRL 797 cultures, respectively. Studies on peptidase system revealed a broad spectrum of activity upon differente substrates for P. pentosaceus CRL 792. This strain also hydrolyzed the pro-pNA substrate indicating proline iminopeptidase activity, which would be involved in the degradation of allergenic peptides. From these results, P. pentosaceus CRL 797 and CRL 792 might be used as novel starter cultures for sourdough fermentation.