Improved organoleptic and nutritive properties of bakery products supplemented with amino acid overproducing Saccharomyces cerevisiae yeasts

Spontaneous yeast mutants isolated in continuous culture as resistant to to xic amino acid analogues, able to increase up to 40 times their free amino acid pool of Thr, up to 160 times their pool of Met, or up to 20 times thei r pool of Lys, were characterized with regard to properties of industrial i nterest. Growth rate, mu (h(-1)), and biomass yield, Y (g/L), of the amino acid overproducing mutants (AA(S)) were in many cases similar to those of t he wild type, whereas their free amino acid content was substantially incre ased in laboratory and industrial media (molasses). Doughs fermented with 3 % baker's yeast and 0.5% AA(S) mutants produced bakery products that displa yed texture similar to those fermented with 3.5% baker's yeast, but the for mer had a considerable improvement of their taste and aroma. On the other h and, bread content of the essential amino acids Lys, Met, and Thr provided by yeast was also increased.