الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Lactic acid bacteria (LAB) are generally recognized as safe organisms that have been used since ancient times in fermentations food. Besides, are able to produce exopolysccharide (EPS) either attached to the cell wall (capsular EPS) or released to the extracellular environment (EPS), LAB, in studies on anti-adipogenesis activity, showed potential effects on the treatment and prevention of diseases without adverse consequences additionally, LAB alleviate type 2 diabetic
without adverse side effects. . In fact, it has been suggested that the health-promoting effect of EPS producing strains are related to the biological activities of these biopolymers Thereby, the present study was undertaken to:- Evaluate some new isolates of lactic acid bacteria, isolated from raw milk and Egyptian artisanal products, for their potential technological and bio-functionality applications- Evaluation of the effect of adding one of the strains and its EPS it produces, which have been isolated and identified, and which have functional properties (anti-diabetic - anti-oxidant - antiinflammatory) on the level of glucose in the blood, kidney and liver function, and the pathological examination of pancreatic tissues in rates injected with streptocytozine (STZ).
This study was conducted as follows:1-Screening exopolysaccharide (EPS)-producing available lactic acid bacterial isolates for their ability to grow and acidify milk.2-Genetic identification of most promising isolates at both genus and species level using 16S r-DNA sequencing. 3-In Vitro screening EPS-producing isolates for their bio-functionalities (including antimicrobial, antidiabetic, and antioxidant activities).4- In vivo evaluation of most active strains, as shown by in vitro screening, for the target bio- functionality (anti-diabetes).The first: Isolation of lactic acid bacteria 220 colonies were isolated from 57 different samples dairy products collected in different governorates of Egypt. The isolates were either cocci in chain or bacilli in pairs or chains. All isolates were catalase negative and gram-positive.57 colonies were selected that could be producers of EPS- polysaccharides. They were selected on the basis of phenotypic shape on the MRS agar and also based on viscosity on MRS broth medium at 37°C. Physical and microbiological tests were conducted on them to choose the best isolates to be selected based on coagulation, viability, viscosity, odor and gas production from 9957 isolates lactic acid bacteria isolated six isolates so that they were high viability, viscosity and no odor or no gas production. The difference in values may be due to the different nature of the isolates, how they are produced EPS or nature of EPS.Detection of EPS-Producing Strains.The EPS-producing strains were detected in three ways.1- Growth of Isolates on the MRS Agar, the appearance of the growth of the EPS-producing. strains on MRS agar, the strains appear mucous, viscous and continuous.
2- Nigrosine Staining, displays the phenotypic shape of the EPS producing strains using the nigrosine dye (negative dye), the EPS producing strain appears luminous while the nonproductive strain is non-luminous.
3- Retinium Red Stain, the method reveals the strains producing EPS in white colour, compared to the reference strain that did not produce EPS and which appears in a pink color. Second- Identification of LAB Isolates Six isolates of LAB that produce EPS were identified by sequencing the 16S rDNA. These sequences were submitted to BLASTN program centre for Biotechnology Information to search the percent of identity with GenBank nucleotide database. The sequences of strains had percent of
identity 99% with the data base existed in the GenBank. Among six isolates, two were identified as Lactobacillus fermentum (FFNL4097 and FFNL3214). Two were identified as Enterococcus faecium(FFNL3036 and FFNL3051). one was classified Enterococcus faecalis FFNL3560. one <was Lactobacillus plantarum FFNL1701.These isolates were from different dairy products that were collect from different regions in Egypt. Several studies have reported that the yield of EPS produced by lactic acid bacteria (LAB)can be influenced by changing the culture conditions or the medium composition. The yield was estimated of the EPS of the six selected strains. Therefore, the effect of some treatments, for
example, different degrees of temperature, pH, and some sugars (sucrose - lactose - fructose) on the amount of yield produced from the strains, was studied -The best treatments for all samples were using fructose, and the lowest were using of lactose. The strain Lactobacillus fermentum FNNL 4097 recorded the highest values, followed by Lactobacillus fermentum FNNL 3214, compared to the control. The effect of same treatments on the EPS content of total sugars was also evaluated.- In general, the use of fructose gave the highest values for total sugars, while the lowest values were when using lactose. - The results also indicated that there were significant differences (p≥ 0.05) between samples in all treatments.