Abstract

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Yoghurt is one of the famous fermented milk preparations. It is the most widely available fermented milk in Western World where its popularity derives more from its flavor versatility. Lactic Acid Bacteria isolated from fermented cow and human Breast milk using MRS agar medium were used to produce yoghurt samples. LAB from commercially prepared yoghurt purchased from the market were used to produce yoghurt which was used as a control for comparison with yoghurts produced using LAB sourced from cow and human breast milk samples. Cow and breast-milk samples were serially diluted and plated out on the MRS Agar using pour plate method. The isolates and the commercially acquired Lactic Acid Bacteria were used to produce yoghurt samples from powdered milk in an 8 hours fermentation process. The fermented product was compared against the commercial product in terms of both nutritional and sensory attributes. The LAB were Lactobacillus acidophilus, Lactobacillus plantarum, and Bifidobacteium. The isolates were used singly as starter cultures. The optimum pH for the Yoghurt production was 5.5 while the optimum temperature is 40oC. The Yoghurt sample C had the highest pH (6.60 ± 0.00; P≤0.05) and highest moisture content (88.10 ± 0.04; P≤0.05), the highest protein content was from sample A and D (control). Sample A had the highest crude fat (0.85 ± 0.00; P≤0.05) ash content was highest in sample D (control) (3.29 ± 0.05; P≤0.05) and the fibre content of the Yoghurt was: 0.14 ± 0.02; P≤0.05. We conclude that the protein content of the yoghurt produced with L. acidophilus has the same protein content with the commercially sourced yoghurt but with lower fats, ash and carbohydrate contents. So, the yoghurt produced with L. acidophilus will be a good source of protein to the consumers. The laboratory and commercially produced yoghurts had equal level of acceptability to the panelists.

Keywords: fermentation, lactic acid bacteria, proximate, powered milk, sensory, yoghurt