Probiotic and technological properties of exopolysaccharide producing lactic acid bacteria isolated from cereal-based nigerian fermented food products

Abstract

The present study aims to evaluate the probiotic potential and technological properties of exopolysaccharide (EPS) producing lactic acid bacteria (LAB) isolated from Nigerian fermented cereal-based foods. Sixty-three autochthonous LAB isolated from cereal-based fermented foods were screened for EPS production, five isolates produced an appreciable amount of EPS on sucrose modified media and were identified by sequencing the 16S rRNA gene as L.plantarum YO175, L.plantarum OF101, P. pentosaceus OF31, W. confusa OF126 and W. confusa WS90. These five isolates were assessed for their probiotic and technological properties viz., tolerance to low pH, bile salt resistance, bile salt hydrolysis, tolerance to simulated gastric transit, cell surface hydrophobicity, antimicrobial, amylolytic and acidifying activity. The LAB isolates showed good survival at pH 2.0 and 2.5 and were resistant to 0.3% bile salt after 4 h. All the isolates tolerate gastric juice condition, with no reduction in viability except W. confusa WS90 that lost viability over 180 min incubation time. L. plantarum OF101 showed the highest hydrophobicity values for n-hexadecane and xylene (43.6%, 46.2%). They all showed different antimicrobial activities against five food-borne pathogens. P. pentosaceus OF31 possessed the highest ability to inhibit pathogens and also demonstrated better and rapid acid production capability. Albeit the properties tested are strain-dependent, L. plantarum and P. pentosaceus strains were found to possess interesting functional and probiotic characteristics to a greater extent compared to W. cibaria strains. The safety investigations indicate their suitability as good candidates for cereal-based probiotic products/starter culture for the improvement of traditional cereal fermentation process and also the development of functional cereal foods.