Technological Properties of Lactic Acid Bacteria Isolated from Different Fermented Foods

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Bakheit, Hunda Abbas
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In this study, a total of twenty five strains of lactic acid bacteria (LAB) were isolated from different Sudanese fermented foods (Sorghum dough, Fermented milk, Cheese, Pickles, and Sausage). Out of which 44% were identified as Enterococci, 40% as Lactobacilli and 16% were identified as Pediococci. Phenotypic and biochemical tests revealed that the Enterococci, Lactobacilli and Pediococci were obligately homofermentative according to their growth characteristics and production of gas (CO2) from glucose fermentation. Following the identification, evaluation of the technological properties namely; acidification activity, production of alpha amylase, haeme-dependant catalase and degradation of anti-nutritive tannins of LAB strains was carried out. Technological properties were investigated with a view towards selection of appropriate starter cultures. Pediococci had the highest rate of acidification with an W10;pH of more than 2 after 12 h incubation. However, Enterococci and Lactobacilli had high rates of acidifying initially (6 h), but W10;pH was below 2 after 12 h incubation. With exception of strains SH1, SH2 and SA6 having W10;pH 2.27, 2.27 and 2.2 respectively. None of the LAB was found to produce ^5;-amylase when grown on MRS containing starch. All isolates of Enterococci, Lactobacilli and Pediococci produced haeme-dependant catalase. Fermentation by Enteroccoci, Lactobacilli and Pediococci as starter culture in sorghum dough batches have ability to reduce the tannin content, however Lactobacilli strain showed the highest ability to degrade tannin (1.7% to 0.9%) in 6 h fermentation. The Enteroccoci and Pediococci strains required 24 h fermentation to reach 1% tannin content.
Fermented Foods
University of khartoum