1 3 Eur Food Res Technol DOI 10.1007/s00217-015-2442-x ORIGINAL PAPER A large diversity of lactic acid bacteria species is involved in the fermentation of wheat used for the manufacture of lemzeiet Ryma Merabti · Farida Bekhouche · Victoria Chuat · Marie N. Madec · Marie B. Maillard · Sylviane Bailly · Anne Thierry · Florence Valence Received: 1 December 2014 / Revised: 8 February 2015 / Accepted: 13 February 2015 © Springer-Verlag Berlin Heidelberg 2015 very similar profiles for both processes. Sixty-nine isolates were identified as belonging to six genera of 16 species (Enterococcus, Lactobacillus, Leuconostoc, Pediococ- cus, Weissella, and Streptococcus). The profiles of volatile aroma compounds showed a marked effect of the fermenta- tion process, compared to non-fermented wheat, with 35 of the 40 volatiles detected at amounts 20- to 30-fold higher in fermented wheat samples. This study gives the first insight into lactic acid bacteria population diversity and activity in fermented wheat and will contribute to a better control of the fermentation process. Keywords Lactic acid bacteria · Fermentation · Cereal · Vinegar · Volatile Abbreviations ANOVA Analysis of variance BHYE Brain heart infusion yeast extract CFU Colony forming unit DMS Dimethyl sulfide DMDS Dimethyl disulfide FA Fat acidity GC–MS Gas chromatography–mass spectrometry HS Headspace LAB Lactic acid bacteria LSD Least significant difference MA Malt agar MRS Man Rogosa and Sharpe OAIC Office algérien interprofessionnel des céréales PCA Principal component analysis pheS Phenylalanyl-t-RNA synthetase alpha-subunit PFGE Pulsed-field gel electrophoresis RAPD Random amplified polymorphic DNA rpoA RNA polymerase alpha-subunit TTA Titratable acidity Abstract Algerian couscous named lemzeiet is manu- factured from fermented wheat. Historically performed in underground silos called matmor, the fermentation of wheat is now generally carried out in plastic jerrycans with or without addition of vinegar at the beginning of the fer- mentation. Culture-dependent and culture-independent methods (PCR-TTGE) were used to characterize lactic acid bacteria and to determine their dynamic and diversity over a two-year period, with and without the addition of vinegar. Fungi, physicochemical characteristics, and volatile com- pound profiles were also monitored. The isolates obtained from different stages of fermentation and from both pro- cesses were characterized by coupling different molecular methods (16SrRNA/pheS/rpoA gene sequencing, species- specific PCR, RAPD and PFGE). PCR-TTGE revealed R. Merabti (*) · F. Bekhouche Département de Biotechnologie Alimentaire, Institut de la Nutrition, de l’Alimentation et des Technologies Agro-alimentaires (INATAA), Université Constantine 1, 25000 Constantine, Algeria e-mail: merabtiryma@yahoo.fr R. Merabti · V. Chuat · M. N. Madec · M. B. Maillard · A. Thierry · F. Valence (*) UMR1253, Science et Technologie du Lait et de l’Œuf, CIRM-BIA, INRA, 65 rue de Saint Brieuc, 35000 Rennes, France e-mail: Florence.Valence-Bertel@rennes.inra.fr V. Chuat · M. N. Madec · M. B. Maillard · A. Thierry · F. Valence UMR1253, Science et Technologie du Lait et de l’Œuf, Agrocampus Ouest, 65 rue de Saint Brieuc, 35000 Rennes, France S. Bailly UMR1331, Toxalim, Research Centre in Food Toxicology, INRA, 31027 Toulouse, France