Gluten breakdown by lactobacilli and pediococci strains isolated from sourdough

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

LETTERS IN APPLIED MICROBIOLOGY

Blackwell Publishing

Lugar: Gran Bretaña; Año: 2006 vol. 42 p. 459 - 464

0266-8254

Aims: To evaluate the growth and metabolic activity of lactobacilli and pediococci strains in a gluten base medium (GBM), formulated for a proper selection of proteolytic strains to be used in sourdough fermentation. Methods and Results: Proteolytic activity by lactic acid bacteria (LAB) was evaluated by SDS-PAGE and by the amino acids released determined by reversed-phase high-performance liquid chromatography. Only 13 LAB (nine lactobacilli and four pediococci), among the 42 evaluated were able to utilize gluten as nitrogen source and to grow in GBM. Pediococcus pentosaceus CRL  797 showed a similar proteolytic activity to lactobacilli strains. In the majority of the cultures, basic amino acid group increased (c. 80% after 12 h incubation)  mainly due to the release of ornithine, a flavour precursor of bread.   Lysine, a limiting essential amino acid in wheat flour, increased by 150% in cultures of P. pentosaceus CRL 797. Conclusions: This study allows selecting P. pentosaceus CRL 797 and L. plantarum CRL 759 as potential starter culture for type III sourdough fermentation. It is shown for the first time that pediococci strains isolated from sourdough are proteolytically active on gluten.