University of Khartoum

Development and Risk Assessment of Functional Probiotic Yoghurt for Lactose Intolerant Individuals

Development and Risk Assessment of Functional Probiotic Yoghurt for Lactose Intolerant Individuals

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Title: Development and Risk Assessment of Functional Probiotic Yoghurt for Lactose Intolerant Individuals
Author: Suliman, Shafag Hassan Mubarak
Abstract: The objective of this study was to develop a functional probiotic yoghurt that is safe for lactose intolerant individuals (LII). A risk assessment on the developed products was run to ensure its suitability for the LII. Three samples of Sudanese fermented bone based food (Dodery) were obtained from El-Fashir city. Six samples of traditional Sudanese yoghurt (Roub) were obtained from Mayo, Shambat, Aldroshab and Ombada (Khartoum State). Cow milk samples were collected from farms close to University of Khartoum farm. Roub and Dodery samples were screened for Lactic acid bacteria and Bifidobacteria. Phenotypic characterization was carried out for all microbial samples. DNA was extracted and purified from isolates according to the phenol/chloroform method. PCR based method was applied to amplify DNA. PCR procedure was performed in 25 µl final volume using iNtRON’s Maxime PCR PreMix Kit (i-Taq(. Molecules of DNA were amplified in a Thermal Cycler lab Cycler SENSQUEST. Eight specific primers pairs were used and PCR products were separated by electrophoresis at 80 V for 80-95 min. Five starter culture combinations were formulated from Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium lactis, Streptococcus thermophilus and Lactobacillus delbrueckii sub sp. bulgaricus. Set yoghurt was made from fresh bovine milk using different mixtures and ratios of isolates and starter cultures. Physicochemical, sensorial and microbiological properties of the developed product were determined at 0, 5 and 10 days of storage. For risk assessment, critical control points (CCPs) in the process of yoghurt production were determined. For each CCP critical limits (CLs) were identified particularly for lactose content. Five CCPs in the manufacturing of low lactose yoghurt were identified. The experiment was run in triplicate. The collected data were statistically analyzed using Statistical Analysis Software (SAS) package. Judged by phenotypic characterization, a total of 65 Gram-positive isolates were recovered (45 from Roub and 20 from Dodery). Sixty five percent were found to be cocci and 32% were identified to be rod. Genotypic characterization of isolates revealed the presence of Lactobacillus genus, Lactobacillus casei, Lactobacillus acidophilus and Streptococcus genus, however were negative for Bifidobacterium genus, Bifidobacterium lactis, Lactococcus lactics and Lactococcus cremoris. Most of Roub and Dodery isolates did not produce a satisfactory yoghurt. However, combination of Lactobacillus casei with Bifidobacterium lactis reduced the lactose content to 0.35%, 0.25% and 0.23% at day 0, 5 and 10, respectively, and produced a yoghurt with acceptable sensory quality. The amount of lactose in the developed yoghurt was way less the 1% level considered to be safe for lactose intolerant individuals. Combination of Lactobacillus casei with Bifidobacterium lactis is recommended for manufacturing probiotic yoghurt low in lactose destined for lactose intolerant individuals.
URI: http://khartoumspace.uofk.edu/123456789/27146


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