A protein concentrate from distillery yeast, and its application to supplement corn tortillas

The purpose of this study was to increase the protein quality of tortillas supplementing them with a protein concentrate obtained from the yeast (Saccharomyces cerevisiae) cream from an alcohol distillery. Rupture of the yeast cell wall was studied, and a procedure for obtaining a high percentage of broken cells from the yeast was developed. A protein concentrate was obtained from the cell-wall free portion. Techniques were developed to obtain the protein concentrate with a low level of nucleic acids. The latter were reduced 91%, and the protein increased 55% with respect to the initial yeast. Different levels of protein concentrate were added to dough made from corn of the Nutricta variety. The resulting tortillas were submitted to a taste panel for sensory evaluation, and the results were statistically analyzed. The highest level of supplementation that did not affect negatively acceptation by the panel was 18% dry weight. In the tortillas with the highest acceptable level of supplementation, protein content increased 60% when compared to the control tortillas, and a significant improvement in lysine content was observed. Nucleic acid content was low, having been reduced to levels which did not represent a limiting factor for the use of yeast in a product destined for human consumption.