Quality parameters and RAPD-PCR differentiation of commercial baker's yeast and hybrid strains

Baker's yeast, Saccharomyces cerevisiae, is a key component in bread baking. Total of 12 commercial baker's yeast and 2 hybrid strains were compared using traditional quality parameters. Total of 5 strains with high leavening power and the 2 hybrid strains were selected and evaluated for their alpha-amylase, maltase, glucoamylase enzymes, and compared using random amplified polymorphic DNA (RAPD). The results revealed that all selected yeast strains have a low level of alpha-amylase and a high level of maltase and glucoamylase enzymes. Meanwhile, the Egyptian yeast strain (EY) had the highest content of alpha-amylase and maltase enzymes followed by the hybrid YH strain. The EY and YH strains have the highest content of glucoamylase enzyme almost with the same level. The RAPD banding patterns showed a wide variation among commercial yeast and hybrid strains. The closely related Egyptian yeast strains (EY and AL) demonstrated close similarity of their genotypes. The 2 hybrid strains were clustered to Turkish and European strains in 1 group. The authors conclude that the identification of strains and hybrids using RAPD technique was useful in determining their genetic relationship. These results can be useful not only for the basic research, but also for the quality control in baking factories.