A theorical practical approach to sourdough starter: microbiology and drying processes

Abstract

Sourdough starter is prepared by mixing flour (traditionally wheat or rye) and water and left to ferment in room temperature (25 – 30 °C). It is a process based on interaction between bacteria (mainly lactic acid bacteria) and yeast (mainly S. cerevisiae and Candida species) present in the ingredients and the tools used, being used as a starter culture in bread making. The final product has enhanced sensorial, functional and nutritional properties. Although it has advantages over baker’s yeast, sourdough needs time and dedication to maintain the microflora viable through the backslopping process, where flour and water is added and the mix is left to ferment in room temperature, this needs to be done every time sourdough is used. Drying techniques could be applied to stabilize the microbiota and avoid the backslopping. The objectives of this work were to gather scientific articles about drying techniques that could be applied to sourdough and perform a technological prospection concerning the starter microbiology, pointing out new technologies and future trends in the market. Freeze- and spray-drying are the most successful methods applied to sourdough, maintaining a good concentration of viable microbes. However, the conditions of the process can affect the microbe survivability. The number of scientific publications and patents has increased over the last 10 years, however no innovations in the market were made. The majority of the patents were deposited by companies while most of scientific articles were developed by universities. The scientific publication profile is different from the patent profile, most of the patents found were about the development of starter and products, while scientific publications concern manly about microbe selection, fermentation products and sourdough starter application.