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Effect of Single Strain and Traditional Mixed Strain Starter Cultures on Rheological Properties of Wheat Dough and on Bread Quality

¹Department of Food Science, Food Technology and Nutrition, National University of Ireland, Cork, Ireland. ²National Food Biotechnology Centre, National University of Ireland, Cork, Ireland. ³Corresponding author. E-mail: e.arendt@ucc.ie. Phone: +353-21-4902064. Fax: +353-21-4270213.

Investigations were made to test the effect of two different sourdough starter culture types on wheat dough and bread quality. Two single-strain starter cultures consisting of well-defined strains of lactic acid bacteria (Lactobacillus plantarum, L. brevis) and a traditional mixed-strain sourdough culture (containing L. crispatus, L. pontis, and Saccharomyces cerevisiae) were evaluated for their effects on the rheological characteristics of wheat dough using both fundamental rheological and standard baking tests. Two other doughs were also evaluated, one which was chemically acidified to a comparable pH value by the addition of lactic acid, and a control which was not acidified. Dynamic oscillation tests were performed using a controlled stress rheometer. The phase angle and the absolute value of the complex dynamic modulus were measured for all doughs at frequencies of 0.1–10 Hz. The addition of sourdough prepared using single-strain or mixed-strain cultures significantly increased the phase angle and reduced the complex modulus of the doughs at all frequencies (P < 0.05). Significant differences were found between the dough which was chemically acidified and those doughs which were biologically acidified. The addition of sourdough effected an increase in loaf specific volume relative to both the chemically acidified and the nonacidified doughs.