Sour dough starter culture

To a limited extent a starter culture once established can be propagated on site (sour dough, yoghurt cultures, yeast in the brewery). 

If the culture is to provide both the yeast and the flavour of sour dough then either it must acquire a wild yeast or a starter culture that includes yeast must be added. In some cases the sour dough culture is only used to give the sour dough taste while conventional yeast is added. 

Marklinder, L, Lonner, C. (1992). Fermentation properties of intestinal strains of Lactobacillus, of a sour dough and of a yoghurt starter culture in an oat-based nutritive solution. 

A natural approach to avoid the use of additives in bread products may be reached by returning to the sour dough process using starter cultures. The use of selected strains with production of specific enzymes is the basis for production of the enzymes and dough conditioners directly in the sour dough. At present, two groups of enzymes are of particular interest in this respect amylases and proteases. 

Our experiments further show that, in regular Danish wheat flour, a maximum of 1% of the total protease enzyme present in the sour dough system can be related to the starter culture, while 99% can be related to the flour. 

Sensory and nutritional aspects. Compared with the traditional sour dough method, the use of well-defined starter cultures offers in addition the possibility of choosing a certain flavour. 

Hansen and Lund, 1987). In rye bread, compounds such as alcohols, esters and carbonyls have been identified (Hansen et al., 1989). Choice of fermentation temperature, dough yield, flour quality and starter culture all influence the sensory properties of the final bread. Free amino acids formed during fermentation increase Maillard reaction products, thus intensifying the taste. Sensory analysis has shown that sour dough rye breadcrumbs had the most intense and bread-like flavour compared with chemically acidified doughs (Hansen et al., 1989). 

Hansen, A., Lund, B., Lewis, M. J. (1989a). Flavour production and acidification of sour doughs in relation to starter culture and fermentation temperature. Lebensmittel Wissenschaft und Technologic, 22, pp. 145-149. 

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