African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5182

Full Length Research Paper

Predominant lactic acid bacteria associated with the traditional malting of sorghum grains

H. Sawadogo-Lingani1*, B. Diawara1, R. K. Glover2, K. Tano-Debrah3, A. S. Traoré4 and M. Jakobsen5
  1Département Technologie Alimentaire (DTA) / IRSAT / CNRST, Ouagadougou 03 BP 7047, Burkina Faso. 2Department of Applied Biology, Faculty of Applied Sciences, University for Development Studies P. O. Box 24, Navrongo, Ghana. 3Department of Nutrition and Food Science, University of Ghana, P. O. Box LG134, Legon-Accra, Ghana. 4Université de Ouagadougou / UFR – SVT / CRSBAN, Ouagadougou 03 BP 7131, Burkina Faso. 5Department of Food Science Food Microbiology, University of Copenhagen, Rolighedsvej 30, 1958 Frederiksberg C Denmark.
Email: [email protected]

  •  Accepted: 05 November 2009
  •  Published: 04 February 2010

Abstract

 

The traditional processes of sorghum grains malting were investigated in Tamale (Northern Ghana) from the raw materials through to the sun-dried malted sorghum including steeping and germination stages. Samples were taken at each processing stage and cultured for the isolation of LAB. The isolates were characterized by basic phenotyping, ITS-PCR / RFLP analysis and identified by partial sequencing of 16S r RNA genes. Their antimicrobial and amylolytic activities and exopolysaccharides production were also investigated. During steeping, the LAB counts in the steep water increased from 105 to 10- 1010 cfu/ml and pH of the steep water decreased from 5.08 ± 0.22 to 4.20 ± 0.50. A total of 106 isolates were identified and the predominant isolates belonged to the species Lactobacillus fermentum (58.49%),Pediococcus acidilactici (22.64%), Weissella confusa (11.32%), Enteroccocus faeciumPediococcus pentosaseus and Lactococcus lactis. Some isolates showed interesting antimicrobial activity (39.62%), slight amylolytic activity (37.73%) and ability to produce exopolysaccharides (90.5%). L. fermentum isolates dominated the microbiota from sorghum grains to malted sorghum. These isolates had technological properties comparable to those responsible for the acidification of sorghum beer (dolo, pito) wort produced from sorghum malt (previously studied), suggesting their potential for use as starter cultures. Suitable isolates of L. fermentum are promising candidates to be used as starter cultures from the initial step of malting, that is, the steeping and are expected to inhibit the growth and survival of pathogens and spoilage microflora, and to control the lactic fermentation of dolo and pito wort or other sorghum malt-based products like infant formulations.

 

Key words: Sorghum, sorghum malt, lactic acid bacteria, identification, technological properties.