Streptococcus thermophilus and Lactobacillus brucei are necessary materials for making yoghurt.Research shows that the bacteria can only reach the upper part of the small intestineHalf, not likeBifidobacteriumThat way we can go to the large intestine.Scientists believe that living yoghurt bacteria (Streptococcus thermophilus and Lactobacillus brucelli) can help people who are lactose intolerant digest lactose, because both bacteria can producelactase。
In addition, Saavedra et al. conducted an experiment: feeding 55 hospitalized infants with Streptococcus thermophilus and two bifidobacteria (200 million live bacteria every day) showed good results.Taking these twoprobioticsOnly 7% of infants in the placebo group had diarrhea, while 31% of infants in the placebo group had diarrhea (p=0.035).In the group taking these two probiotics, rotavirus was found in the feces of only 3 (10%) infants, while in the placebo group, rotavirus was found in the feces of 10 (39%) infants (p=0.025).
Streptococcus thermophilus
Another clinical trial was conducted on 70 overweight adults.These people tookenterococcus faecium And Streptococcus thermophilus.They drink 450 ml every day, fermented with these two kinds of bacteriaYogurt。After 8 weeks, their low-density cholesterol in blood decreased by 8.4% (p<0.05), whileBlood FibrinThe concentration of.
characteristic
Announce
edit
[1]Streptococcus thermophilus comes from dairy products.It is an oxygen consuming leatherLan's positive bacteriaThe two oval shaped cocci form a long chain of about 0.7 to 0.9 microns.staySelective mediumStreptococcus thermophilus will grow into beige colonies.
Streptococcus thermophilus-metabolizeIt is the same type of fermentation bacteria as Streptococcus thermophilus,fermentationIn the process, it produces L-lactic acid and folate.Under laboratory conditions, Streptococcus thermophilus canculture medium(Commercially available media for the cultivation of Streptococcus thermophilus).
The degradation of lactose requires a special enzyme calledβ - galactosidase。Lactose intolerant people lack this enzyme.
Streptococcus thermophilus
Streptococcus thermophilus individuals are mostly connected by two spheres, three or four spheres, five or six spheres, and rarely connected by more than eight spheres and single spheres.So there is a big difference in individual size.Most of them are within the range of 0.4-0.7 * 1.0-6um.
Related characteristics
Announce
edit
Microbes that can be classified as probiotics need to remain active when reaching the intestinal tract.For this reason, these bacteria should be alive when passing through the gastrointestinal tract.Therefore, the effect of bacteria on gastric acid and bile saltTolerance, is a basic step for screening probiotics, even if the experiment in this step is conducted in vitro.
Gastric juicePH valueThe pH value of gastric juice is 6 at breakfast, 5 at lunch, and lower than 5 and higher than 4 at dinner.The survival rate of Streptococcus thermophilus in acid solution with PH=6.8 is 100%, that in acid solution with PH=4 is about 75%, and that in acid solution with PH=3 is about 70%.
secretionBile saltIt is a physiological mechanism of the body against foreign microorganisms.The experimental results showed that bile salt had a certain inhibitory effect on the growth of thermophilic streptococcus (the inhibitory rate was 28%).However, this kind of probiotics can survive in high concentration of bile, so it should be able to avoid bile damage in the body and reach the far end of the small intestine.
The degree of inhibition of Streptococcus thermophilus on intestinal pathogens is that when it is co cultured with these pathogens in vitroculture mediumFormed oncolony of bacteriaThe percentage of diameter reduction.Ifpathogenic bacteriaIf the colony diameter is reduced by 90% due to the inhibition of probiotics, it can be said that the probiotics completely inhibit the growth of the pathogenic bacteria.
Streptococcus thermophilus seems to be able to regulateinflammationSeveral immune factors of the index.
In vitro, experiments with human intestinal epidermal cells showed that Streptococcus thermophilus could significantly reduce the production of interleukin-6.However, Streptococcus thermophilus can reduce the expression of IL-8, IL-10T cell growth factorTGF-β、tumor necrosis factorThe production of TNF - α has no regulating effect.
Another in vitro experiment showed that Streptococcus thermophilus could significantly increase the production of interleukin IL-12, interferon INF - γ and tumor necrosis factor TNF - α in mouse spleen cells.The probiotics can also increase the production of interleukin IL-4.
effect
Announce
edit
Streptococcus thermophilus is considered as a "GRAS" ingredient and is widely used in the production of some important fermented dairy products, including yogurt and cheese (such asSwitzerland、Limburg cheese）。Streptococcus thermophilus also has some functional activities, such as productionExtracellular polysaccharide、BacteriocinAnd vitamins.In addition, Streptococcus thermophilus can also be regarded as a potentialprobiotics , experiments have proved that it has health effects, transport activity and certain gastrointestinal tractAdhesion。Therefore, we need to explore that different thermophilic streptococci produce differentmetaboliteThe ability of fermentation is not only the amount of lactic acid produced.
1. Improve intestinal microenvironment
Reduce intestinal pH, promote intestinal peristalsis and preventPathogenColonization, secretionBacteriocinInhibiting the growth of pathogenic bacteria.
2. Regulate blood pressure
It can inhibit the activity of cholesterol synthase, reduce the cholesterol content in serum, and its bacterial fermentation products can regulate and control blood pressure.
3. Anti cancer effect
Generated polysaccharideBacteriocin, lactic acid, etc. have anti-tumor activity, which can inhibit
The survival rate of Streptococcus thermophilus in acid solution with PH=6.8 is 100%, that in acid solution with PH=4 is about 75%, and that in acid solution with PH=3 is about 70%.
Streptococcus thermophilus can survive in high concentration of bile, so it should be able to avoid bile damage in the body and reach the far end of the small intestine.
7. Shorten the curdling time of yoghurt
The application of Streptococcus thermophilus in fermented yoghurt can greatly shorten the curdling time of yoghurt.Fermented yoghurt with non thermophilic streptococcus
The coagulating time of fermented yoghurt added with Streptococcus thermophilus can be controlled within 5h, which is beneficial to the industrial production
Industrialized production.
8. Increase the viscosity of yogurt
Streptococcus thermophilus can be produced in large quantities during fermentationExtracellular polysaccharide(Exopolysaccharide, EPS), extracellular polysaccharide
Polymers as thickeners and gelling agents increased the viscosity of fermented milk and improved the quality of yogurt.
other
Announce
edit
Whether infants can eat Streptococcus thermophilus
According to the regulations of mainland China, Streptococcus thermophilus cannot be added to baby food.
