Spray-dried and freeze-dried sourdough powders: Properties and evaluation of their use in breadmaking

In this study, spray-dried and freeze-dried sourdough powders were produced and characterized. In addition, the powder samples were used to produce sourdough breads. Differences observed in powder properties of sourdough powders (particle surface morphology, bulk density and flowability) depending on the method used. The powder samples were used at four blending ratios (3, 6, 9 and 15%) to assess the effect of their use on physico-chemical properties of sourdough breads produced. Converting sourdough into powder preserved the viability of both lactic acid bacteria and yeasts at certain numbers (final counts for both LAB and yeast were around 5 cfu/g and 8 cfu/g for freeze-dried powder and spray-dried powder, respectively). Satisfactory results were obtained with both spray dried and freeze dried sourdough powders even though there were significant changes in some dough properties and reduction of volume of bread products when powder starters used in comparison with control samples (p < 0.05). Therefore, the results obtained in this study suggest that freeze-dried and spray-dried sourdough powders could be used as alternatives to fresh sourdoughs in dough formulations.