Effect of fermentation rate on endogenous leavening of Candida milleri in sour rye dough

Sourdough leavened breads rely upon an active yeast strain in the mature sourdough to provide the leavening capacity needed in the bread dough. A strain of Candida milleri yeast, previously known as a good gas producer, was grown together with a homofermentative or a heterofermentative lactobacillus in sourdough at 22, 25 or 28 °C in a one stage re-inoculation procedure. The focus was to recognize fermentation conditions of the sourdough (dough yield, DY250) favoring leavening in the final bread dough (DY200). Endogenous leavening of bread dough was enhanced by low temperature during the sourdough fermentation. The lower temperature delayed acidification of the sourdough, shortening the time that the yeast was exposed to high acidity and especially undissociated acids. This resulted in a higher leavening of the bread dough in both sourdoughs. The results suggest that it is possible to improve endogenous leavening capacity by optimizing the industrial sourdough process.