Addition of Inulin and Manganese Chloride Increased Antibacterial Metabolites in Yoghurt

• Published in: Pakistan journal of nutrition : PJN 2014, Vol.13 (1), p.12-16
• Main Authors: Ogueke, Chika C., Owuamanam, Clifford I., Olawuni, Ijeoma A., Iwouno, Jude O., Peter-Ikec, Ann I.
• Format: Article
• Language: English
• Subjects: Escherichia coli; Staphylococcus aureus
• ISSN: 1680-5194; 1994-7984
• DOI: 10.3923/pjn.2014.12.16

The effect of the addition of inulin and manganese chloride (MnCl sub( 2)) to milk before fermentation on the amount of antibacterial metabolites produced in fermented milk was studied. Normal and modified fermented milks were produced and the lactic acid and hydrogen peroxide (H sub( 2)O sub( 2)) contents were determined using standard analytical procedures. The well in agar diffusion method was used to determine the antibacterial effects of the cell free fermented milks on Staphylococcus aureus and E. coli. Results obtained showed that addition of the compounds increased the amount of lactic acid and H sub( 2)O sub( 2) in the modified milk. Highest amounts of lactic acid (6197.50 mg/L) and H sub( 2)O sub( 2) (42.83 mg/L) were obtained in the sample containing highest amounts of inulin (7 g/L) and MnCl sub( 2) (2 mg/L). The largest zones of growth inhibition for S. aureus and E. coli were obtained in samples containing 5 g/L inulin, 2 mg/L MnCl sub( 2) and 7 g/L inulin, 2 mg/L MnCl sub( 2), respectively. However, larger zone of growth inhibition were generally observed with E. coli. The inclusion of these substances significantly increased the amounts of the antibacterial metabolites and increased the inhibitory effect on S. aureus and E. coli. Therefore addition of such compounds to milk before fermentation should be encouraged to improve the probiotic and health potentials of fermented milk.