The survival of probiotics is affected by many factors, such as temperature, pH, pressure, gastric acid, bile salts, etc. Most of the probiotic products currently on the market cannot effectively pass through the stomach because gastric acid is a strong acid, and probiotics cannot survive in strong acids with a pH value of less than 3. Studies have found that the survival rate of probiotics in gastric juice is mainly related to the bacterial species and product type (bacterial powder, embedded granules, crystal balls, enteric-coated capsules, enteric-coated tablets).
For the same product type, the survival rates of different probiotic strains in gastric juice are quite different. Some scholars compared the tolerance of six kinds of powdered probiotics to gastric juice. The results are shown in Figure 1. There are certain differences in the survival rates of different probiotics in gastric juice environments with different pH values. The survival rate of all products is higher than 80%. The probiotics in product D can survive well when the pH is 3.5. The survival rate of product E is the highest (78%) when the pH is 1.5, while the survival rates of C and F are 0%. Although the number of viable bacteria in the six products all meets the national standard requirements, there are differences with the labeled numbers. The probiotics in the six products have better tolerance in simulated gastric juice environments with pH values of 4.5, 3.5, and 2.5. In simulated gastric juice of <1.5, the survival rate was significantly reduced.
Figure 1 Survival rate of probiotics after digestion in simulated gastric juice at different pH for 2 hours
Compared with powdered probiotics, the use of encapsulation technology can improve the survival of probiotics under adverse environmental conditions and improve their survival rate in the host body. The study found (Table 1) that 7 kinds of powdered probiotics have poor tolerance to artificial gastric juice because they have not been embedded. A certain granular probiotic, a certain domestic crystal ball, a certain Japanese crystal ball, and a certain capsule probiotic, Shengbang Bubujia Intestinal Diluted Probiotics all showed good resistance to artificial gastric juice, and the survival rate in artificial gastric juice was higher than that of powdered probiotics, indicating that the embedded probiotics have better resistance to gastric juice digestion ability, the corresponding probiotic survival rate is also higher, which can provide a reference for the selection of probiotic supplement preparations.
Table 1 Theoretical viable bacterial counts of 12 kinds of probiotics and the viable bacterial counts after digestion with artificial gastrointestinal fluid
references:
[1] Li Yuyuan, Zhang Yan, Liu He, et al. Comparison of tolerance levels of different types of probiotic preparations in the gastrointestinal tract [J]. Chinese Journal of Microecology, 2021, 33(12): 1374-1378.DOI: 10.13381 /j.cnki.cjm.202112002.
[2] Zhang Linqi, Wang Xiaorui, Shi Chang, et al. Research on the stability of live bacteria in probiotic powder and their tolerance to simulated gastrointestinal fluid [J]. Food and Fermentation Industry, 2021, 47(13): 36-42.DOI :10.13995/j.cnki.11-1802/ts.026407.