Effect of respirative cultures of Lactobacillus casei on model sourdough fermentation

• First study on the influence of respirative cultures of LAB on food matrix.
• Respiration-competent Lactobacillus casei N87 improves sourdough volatilome.
• Respiration-competent L. casei N87 improves sourdough proteolysis.
• The respirative phenotypes of LAB may be useful in food fermentations.

Aim of the study was to evaluate the effect of respiratory metabolism of Lactobacillus casei species on qualitative characteristics of sourdough. For this purpose, the respiration-competent strain L. casei N87, grown both in anaerobic (AN) and respiratory (RS) condition, was used as starter culture, in combination with the yeast (Y), in model wheat dough fermentation. Three mixed starter cultures were designed for dough fermentation, namely, L. casei RS + Y, L. casei AN + Y, and Y; a control sample C was produced without starter. At time zero and after 6 and 24 h of fermentation the doughs were analyzed for pH, total titratable acidity, lactic acid bacteria and yeast concentration, volatile organic compounds production by SPME-GC/MS and the changes in albumin/globulin, gliadin and glutenin fractions by SDS-PAGE.The respirative strain L. casei N87 affected significantly the characteristics of the dough showing major acidification, increased biomass, and different volatile (higher production of diacetyl, acetic acid, acetoin, ethyl acetate) and proteolytic profiles compared to the anaerobic culture L. casei N87. The findings proved the significant role for respiratory cells of L. casei N87 in the definition of acidification, aroma and proteolysis during dough fermentation suggesting a potential role in influencing flavor and structure of baked goods.