| Blood lipid lowering functional property of Lactic acid bacteria fermented milk beverage has theory and practical application value. Five Lactic acid bacteria with good functional properties were used as research objects, the effect of mix fermentation and conditions on blood lipid lowering functional property was explored. The main results were as follows:(l)The effects of mixed stains fermentation on fermentation properties and external functional properties were studied. Five Lactic acid bacteria isolated from longevity crowd in Bama district and traditional dairy products in Xinjiang were used. The five strains were Lactobacillus. plantarum s7, Lactobacillus. rhamnosus grx10, Lactobacillus. casei g9, Lactobacillus. acidophilus k4, Bifidobacteria. longum w10. The effects of single and mixed Lactic acid bacteria on functional properties of fermented milk were reserached, using bacteriostatic ability, antioxidant ability, cholesterol and triglyceride reducing ability, a-glucosidase inhibition ability as subjects. Principal component analysis was used to analysis the comprehensive score of those functional properties. The results showed that the acid producing ability of mixed Lactic acid bacteria was higher than that of single strain, the acidity was of 177.96°T after fermentating at 37℃ for 24h, the growth rate was faster, cultivated about 3h reached logarithmic phase, around llh reached plateau phase, and the number of living bacterium was higher than that of single strain. The inhibition ability to Escherichia coli, Staphylococcus aureus and Salmonella bacteria was stronger than single strain, bacterio static circle diameter were 18.01 mm,17.34 mm and 17.85 mm respectively. The O2- clearance ability of the mixed strains fermented milk was higher than any single strain fermented milk which was 38.83%, the DPPH·and·OH clearance rate were higher which were 58.85%,72.10% respectively, the reducing power A700 and SOD activity were higher which were 0.3868,8.90 U/mL Cholesterol and triglyceride degradation rate were higher than that of single strain which were 39.69% and 20.67% respectively; the a-glucosidase inhibition rate just little lower than Lactobacillus. rhamnosus grx10 and Lactobacillus. plantarum s7 fermented milk which was 50.24%. Principal component analysis showed that four principal components were extracted, which were respectively characterized by reduction ability, Escherichia coli inhibition activity, DPPH clearance ability, O2- clearance ability. The cumulative contribution rate was 95.1%, which was enough to explain the changing trend of those 11 functional indicators. The comprehensive score of those 11 functional indicators of the mixed strains fermented milk was higher than all single strain fermented milk.(2)The fermentation conditions and formula optimization of mixed strains fermented beverage were studied. The influence of fermentation temperature and time and the adding amount of traditional Chinese medicine, low poly fructose, bananas on fermentation and external functional properties were researched, the results showed that fermented conditions were determined for 38℃,24 h, the appropriate adding amounts were 15%,3%,15% respectively. The lactic acid bacteria beverage formula was optimized by response surface, it was concluded that:whey powder processing material and skimmed milk as fermentation substrate (including 5% whey powder and 3% dried skim milk), Chinese medicine extract content is 17.65 g/100 g, low poly fructose content is 3.12 g/100g, banana content is 13.84 g/100g. Under that condition, living bacterium number was 9.42 LogCFU/mL, DPPH·, ·OH, O2- clearance rate, reducing power A700 were 70.24%,56.39%,57.89% and 1.0 respectively, the inhibition diameter of E.coli, Salmonella, Staphylococcus aureus were 19.03 mm,19.45 mm and 16.05 mm respectively, a-glucosidase inhibition rate was 38.45%.(3)Storage stability of mixed strains fermented beverage was studied. The changes of pH, acidity, living bacterium number, functional properties were studied at 4℃ and room temperature storage during 60 d. The results showed that after 60 d at 4℃ and room temperature,the acidity increases by 114.5°T to 114.5°T ,229.4°T , pH dropped from 3.89 to 3.48, 2.95, living bacterium number fell from 9.42 LogCFU/mL to 8.11 LogCFU/mL,7.32 LogCFU/mL. The antioxidant ability indicators of DPPH·, ·OH, O2- clearance rate, reducing power dropped from 70.24%,56.39%,57.89%,1.0 to 63.21%,50.01%,52.02%,0.94 respectively at 4℃,52.21%,38.98%,44.01%,0.84 respectively at room temperature. The inhibition diameter of e.coli, salmonella, staphylococcus aureus rised from 19.03mm,19.45mm and 16.05mm to 25.1mm,25.8mm and 22.4mm at 4℃,28.01mm,29.10mm,25.30mm at room temperature.The a-glucosidase inhibition rate fell to 32.11%,29.15%. Overall, living bacterium number of lactic acid bacteria beverages can maintain higher level, the functional properties remain relatively stable, storage stability at 4℃ storage condition is better than the room temperature.(4)Effect of mixed strains fermented beverage on blood lipid was studied by establishing the model of hyperlipidemia rats and lavaging mixed strains fermented beverage. It was found that mixed strains fermented beverage can significantly reduce TC, TG, LDL-C and ApoB levels (P<0.05)of hyperlipidemia rats, the possible mechanism were reduced the TC, TG content in liver, and increased TC, TG, TBA and moisture content in feces; in antioxidant ability, significantly reduced ALT, AST and MDA content(P<0.05), significantly increased SOD activity and GSH and GSH-PX activity in liver (P<0.05); significantly reduced liver cell apoptosis percentage.Vivo experiments established that mixed strains fermented beverage can help to lower blood lipid levels, improved the antioxidant ability of rats, realized the blood lipid lowering effect, the effect was better than mixed strains fermented beverage(no Chinese traditional medicine adding)and grx10 fermented beverage. |
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