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Microbiological and Fermentative Properties of Baker's Yeast Starter Used in Breadmaking
Author(s) -
Reale A.,
Di Renzo T.,
Succi M.,
Tremonte P.,
Coppola R.,
Sorrentino E.
Publication year - 2013
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/1750-3841.12206
Subject(s) - yeast , food science , biology , temperature gradient gel electrophoresis , leuconostoc , lactobacillus , pediococcus , enterococcus faecalis , food spoilage , bacteria , microorganism , lactobacillus plantarum , microbiology and biotechnology , enterococcus , fermentation , lactic acid , 16s ribosomal rna , biochemistry , genetics , staphylococcus aureus
This study assessed the levels of microbial contaminants in liquid, compressed and dry commercial baker's yeasts used as starters in breadmaking. Eumycetes , Enterobacteriaceae , total and fecal coliforms, Bacillus spp., and lactic acid bacteria (LAB), in particular enterococci, were quantified. Results obtained in this study highlighted that baker's yeast could represent a potential vehicle of spoilage and undesirable microorganisms into the baking environment, even if these do not influence the leavening activity in the dough, as ascertained by rheofermentometer analysis. Different microbial groups, such as spore‐forming bacteria and moulds, were found in baker's yeast starters. Moreover, different species of LAB, which are considered the main contaminants in large‐scale yeast fermentations, were isolated and identified by Denaturing Gradient Gel Electrophoresis (DGGE) and 16S rDNA sequencing. The most recurrent species were Lactobacillus plantarum , Enterococcus faecalis , and Enterococcus durans , isolated from both compressed and dry starters, whereas strains belonging to Leuconostoc and Pediococcus genera were found only in dry ones. Nested‐Polymerase Chain Reaction (Nested‐PCR) and Randomly Amplified Polymorphic DNA–PCR (RAPD‐PCR) were also used to highlight the biodiversity of the different commercial yeast strains, and to ascertain the culture purity.