Influence of temperature and of starter culture on biochemical characteristics and the aromatic compounds evolution on type II sourdough and wheat bread

This study evaluated the effect of the addition of different starter cultures and of fermentation temperature for acidity, fermentation properties, and volatile compounds production (VCP) in type II sourdough. Sourdoughs were fermented at 28 and 35 °C by nine different combinations between Lactobacillus amylovorus, Lactobacillus brevis, Lactobacillus plantarum, Lactobacillus reuteri and Pediococcus pentosaceus. Thereafter, four starter cultures were selected for sourdough loaves production and compared to the control (without sourdough), in relation to hardness, pH and VCP evolution. Principal Component Analysis identified that 44.10% of the differences between the sourdoughs resulted from the change in temperature. At 28 °C, were observed an average increase of 50% in yeast cell density, glucose consumption, of 257% in CO2 production, and 50% lower acidity. VCP was influenced by temperature and starter culture, at 35 °C more aldehydes, esters and fewer alcohols were identified. Sourdough loaves showed 38% more VCP with aromas of flowers and fruits than the control. But also had an increase in the crumb hardness, which had a strong negative correlation with the pH (r = 0.81). However, L. brevis and L. plantarum at 35 °C, produced a loaf with great acidity, statistically similar hardness, and with more fruity flavored compounds than the control.