Gluten breakdown by lactobacilli and pediococci strains isolated from sourdough

CARLA L. GEREZ; GRACIELA C. ROLLÁN; GRACIELA FONT DE VALDEZ

LETTERS IN APPLIED MICROBIOLOGY

Blackwell Publishing

Año: 2006 vol. 42 p. 459 - 464

0266-8254

SUMMARY Aims: To evaluate the growth and metabolic activity of lactobacilli and pediococci strains in a gluten-based 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 (aa) released determined by RP-HPLC. Only 13 LAB (nine lactobacilli and four pediococci), among the forty-two 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 aa group increased (ca 80% after 12-h incubation) mainly due to the release of ornithine, a flavor precursor of bread. Lysine, a limiting essential aa in wheat flour, increased by 150% in cultures of Ped. pentosaceus CRL 797. Conclusions: This study allows selecting Ped. pentosaceus CRL 797 and Lact. 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 Significance and Impact of Study: The physiological studies on gluten breakdown by LAB will contribute to the better selection of strains to produce breads with enhanced organoleptic characteristics.