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 toxic 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 their pool of Lys, were characterized with regard to properties of industrial interest. Growth rate, μ (h-1), and biomass yield, Y (g/L), of the amino acid overproducing mutants (AAS) were in many cases similar to those of the wild type, whereas their free amino acid content was substantially increased in laboratory and industrial media (molasses). Doughs fermented with 3% baker's yeast and 0.5% AAS mutants produced bakery products that displayed texture similar to those fermented with 3.5% baker's yeast, but the former had a considerable improvement of their taste and aroma. On the other hand, bread content of the essential amino acids Lys, Met, and Thr provided by yeast was also increased. Keywords: Bakery products; organoleptic properties; nutritive properties; amino acid enrichment; amino acid overproducing yeasts