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Study of the micro‐organisms associated with the fermented bread (khamir) produced from sorghum in Gizan region, Saudi Arabia
Author(s) -
Gassem M. A. A.
Publication year - 1999
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.1999.00648.x
Subject(s) - fermentation , food science , lactobacillus brevis , enterobacter aerogenes , rhizopus oryzae , biology , penicillium , lactic acid , pediococcus acidilactici , mucor , rhodotorula , rhizopus , bacteria , microbiology and biotechnology , lactobacillus plantarum , yeast , biochemistry , genetics , escherichia coli , gene
Traditional bread (khamir) was made from sorghum flour of two local varieties, Bayadh and Hamra. The bread was prepared by mixing the sorghum flour with water and spices (onion, garlic, lemon juice and fenugreek) in a 1:0·8 (w/w) ratio and fermented for 24 h at 30 °C. Two other fermentations were carried out using an inoculum from the previous fermentation. The micro‐organisms were isolated from different plates and identified using different characterization systems. Both total bacterial populations and lactic acid bacteria increased with fermentation time and reached the highest number at 16 h (first fermentation) and at 8 h (second and third fermentation). The content of lactic acid was increased with time to reach 1·2%, but the increase was higher for the second and third fermentations (1·6% each). The pH dropped with time from 6·77 to 4·35 in the first fermentation and from 6·65 to 4·18, and 6·57–3·93, in the second and third fermentations, respectively. The micro‐organisms, which were isolated and characterized during the 24 h fermentation, included: bacteria ( Pediococcus pentosaceus , Lactobacillus brevis , Lact. lactis subsp. lactis , Lact. cellobiosus , Klebsiella oxytoca , Kl. pneumoniae , Enterobacter aerogenes , Ent. sakazakii, Serratia marcescens and Ser. odourifera ), moulds ( Penicillium sp., Rhizopus sp., Aspergillus niger , Alternaria sp., Fusarium sp. and Mucor sp.) and yeasts ( Candida parapsilosis, C. orvegnsis and Rhodotorula glutinis ) .