Growth kinetics and biomass characteristics of Lactobacillus plantarum L14 isolated from sourdough: Effect of fermentation time on dough machinability

Screening of the kinetic behavior of microorganisms is essential for industrial production planning, determining the changes depending on environmental factors and designing technologically the optimum reactor. In this study, the growth kinetics of Lactobacillus plantarum L14 naturally existing in sourdough was investigated in order to determine its biotechnological performance and the role of the effect on the fermentation process during dough-making. Growth kinetics of L. plantarum L14 were examined at 37 degrees C for 28 h fermentation using MRS medium. The maximum specific rate of L. plantarum L14 in the exponential phase was calculated to be 0.551 h(-1) and the productivity was 1.08 g/Lh. When the stationary phase was reached, maximum increase of 2.9 log cfu/mL was observed and average biomass productivity was determined as 9.19 g/L (2.14 g/L on dry matter basis). Cell sizes of L. plantarum L14 were examined using a particle size analyzer; D(4,3 )and D-90 results were measured as 4.38 and 9.01 mu m, respectively. Wheat doughs prepared by adding L. plantarum L14 biomass were fermented for 1, 15, 20 and 25 h and the acidity, cell number and machinability properties of the doughs were investigated. With increasing acidity during fermentation, more cohesive and sticky dough formation was detected.