Ciencia España , Salamanca, Lunes, 09 de julio de 2018 a las 08:51

New fermentation starter allow the development of bread and other innovative products without gluten

A research from the University of Salamanca combines different yeasts and lactic acid bacteria to improve the quality of bread made with wheat flours or corn and rice flours, suitable for celiacs

FGUSAL/DICYT A research project of the Institute of Functional and Genomic Biology (IBFG, a mixed center of the CSIC and the University of Salamanca) in collaboration with the University of Salamanca's Department of Microbiology and Genetics is developing new starter for bread fermentation. After isolating numerous beneficial microorganisms from natural sourdoughs, the researchers selected the best strains and formulated two prototypes, one for fermentation of wheat flours and the other for gluten-free corn and rice flours.


"We have used a series of microorganisms isolated in other projects, both from cereal grains, as well as from different flours and bread dough and we have combined them in different formulations to efficiently ferment wheat flour, Tritordeum or specific gluten-free flours in order to obtain some bread products with new and good organoleptic, nutritional and sensory characteristics, ", explains Mercedes Tamame González, CSIC researcher at the IBFG.


One of the new prototypes has been formulated for wheat flours and allows to improve some aspects of bread such as aroma, flavor and its expiration date. The second prototype is especially important for fermenting corn and rice flours, in which commercial yeast is often used along with numerous additives, such as thickeners and gums, which substitute the effect of gluten. The use of these starters would allow eliminating some of these additives.


Testing different combinations of microorganisms


Previously, researchers have isolated a large number of strains of three types of microorganisms: "wild" fermentative yeasts of the Saccharomyces cerevisiae species, other non-fermentative yeast species, and lactic acid bacteria. They come mainly from natural sourdoughs or from spontaneous fermentation made with different flours from Castilla y León. All these results were achieved thanks to the collaboration of the Zamora Bread Manufacturers Association (ASEZPAN).


Now, they have gone a step further thanks to the Proof of Concept call from the General Foundation of the University of Salamanca, within the TCUE program of the Regional Government of Castilla y León, co-financed with FEDER funds. In the laboratory, they have carried out experiments using different combinations and formulations. "We carry out tests on different types of flours and we elaborate small-scale bakery products to analyze which combinations and cellular quantities of microorganisms are the best for fermenting them and for developing bread with certain characteristics", explains the IBFG researcher.


Different yeasts and lactic acid bacteria


Almost exclusively commercial yeast of the species Saccharomyces cerevisiae is used in the fermentation of industrial bread commercialized in Spain, which generates the characteristic carbon dioxide of the fermentation process, in addition to conferring to the bread some distinctive properties depending on the strain that has been used. On the other hand, "we have combined two wild strains of Saccharomyces different from the commercial ones with two strains of unconventional yeasts of the genera Wickerhamomyces and Kazachstania in our prototypes, which can provide enzymatic activities capable of hydrolyzing macromolecules of the corn and rice flours, plus some other desirable characteristics. Thus, one of the prototypes can be applied to products for celiac people or with different gluten intolerances, "says María Ángeles Santos García, a researcher at the Department of Microbiology and Genetics of the University of Salamanca.


To develop these new starters, researchers have also combined previous yeast with other types of microorganisms, certain lactic bacteria isolated from bakery dougs. Specifically, they have selected two strains of Lactobacillus and Weisella that can also provide favorable substances for the "bread made with the flours they use.


Mercedes Tamame believes that in Spain "there is a gap in this type of studies, which are frequent on the Italian, French and Belgian dougs Italy, as well as in other European countries." The research teams led by her and by María Ángeles Santos have the necessary know-how to fill that gap since, as a part of their previous work, they have analyzed many different dougs and have a collection of about 500 strains of yeast and 750 lactic bacteria.