Isolation and screening of lactic acid bacteria with the ability to remove cholesterol and lower nitrite from cured beef and its fermentation performances
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Graphical Abstract
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Abstract
18 strains of lactic acid bacteria were isolated from traditional fermented cured beef.The o-phthalaldehyde method was used to determine the amount of cholesterol,the rate of cholesterol- degrading of strain NR7 was 22.61%.The N-( 1- Naphthyl)- ethyl- enediamine dihydrochloride method was used to determine the amount of nitrite,after inoculating 12 h and 24 h,the amount of degeneration of nitrite were 34.177 μg / m L and95.82 μg / m L,respectively.In the p H3.0 environment,the viable bacteria rate of NR7 was 99.50% and able to tolerate0.3% bile salts.Therefore,NR7 strain was selected as the target strain,and the production adaptability had to be further researched.After inoculating 4 h,it can produce acid quickly.It can also grow under 15~40 ℃,and be able to tolerate 8% Na Cl and 200 mg / kg Na NO2.After the vacuum freeze drying,the rate of survival live was 93.62%.After preserving 30 d at 4 ℃,the survival rate of bacteria was 89.99%.The NR7 strain was identified as Lactobacillus plantarum by 16 S rRNA sequencing.
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