Spontaneously fermented ancient wheat sourdoughs in breadmaking: Impact of flour quality on sourdough and bread physico-chemical properties

In this study changes during fermentation of spontaneously fermented modern and ancient (spelt, emmer, and khorasan) wheat sourdoughs and their feasibility to act as leavening agents in breadmaking were evaluated. During 6 h of fermentation, sourdough was characterized for lactic acid bacteria and yeasts counts, pH, total titratable acidity (TTA), proteolytic activity, rheological and electrophoretic profiles. The effects of 25 and 50 g/ 100g sourdough addition on physico-chemical and sensory properties of refined wheat flour bread were also investigated. Although in all sourdoughs a pH drop, increase in proteolytic activity, gliadin and glutenin degradation with fermentation were recorded, due to different flour composition and microbial activity, tested sourdoughs significantly differed in rheological properties and breadmaking quality. Wheat sourdough being characterized by the highest acidification, increase in proteolytic activity, and the most extensive hydrolysis of gliadins, resulted in bread with the lowest specific volume and hardest crumb texture. Emmer sourdough, having the highest TTA, ash and wet gluten content, exhibited the highest extensibility, the least pronounced changes in proteolytic activity and the electrophoretic pattern which produced bread with the highest volume and softest texture. In general, ancient wheat varieties have shown great potential in sourdough breadmaking in comparison to modern wheat.