Abstract

The study evaluated viability of probiotic lactobacilli in roselle extract at two different temperatures with view to producing acceptable and health beneficial probiotic beverage. Lactobacillus species isolated from fermented sorghum, maize grains and yoghurt samples were characterized and then inoculated into sterile roselle juice samples. Samples were stored at ambient (27 ± 2°C) and refrigeration temperatures (4 ± 1°C) over a period of four weeks and the viability of the probiotic isolates investigated by using standard methods. Antimicrobial effect of the probiotic isolates on two selected food borne-borne pathogens (Escherichia coliand Staphylococcus aureus) was also determined by the broth culture method. Results showed that the strains (Lactobacillus acidophilus and Lactobacillusplantarum) remained viable in the beverage for 27 days. Except for L. acidophiluswhich decreased gradually after 21 days of storage, other strains (L. plantarum) (Ry and Rm) increased from an initial count of 1.0 x 106 to 6.4 x 106 and 9.8 x 106 cfu ml-1 respectively in samples kept at ambient temperature. The results further revealed that the probiotic isolates exhibited varying degree of inhibition against the two selected food-borne pathogens with greater inhibition exhibited against E. coli.

Key words: Roselle extract, probiotics, viability beverage