What strains are commonly used in yogurt fermentation?

What kinds of bacteria are commonly used in yogurt fermentation? Let's take a look at Bian Xiao's sharing today.

1, classical mixed fermentation

This fermentation is the mixed fermentation of Lactobacillus bulgaricus and Streptococcus thermophilus, which are the classic strains of yogurt processing, at the ratio of 1: 1, or 1: 2.

The fermentation characteristics of the two strains are complementary, and the yogurt made from them has the composite health care value of the two strains.

2. Mixed fermentation of Bifidobacterium

This fermentation is a mixed fermentation of Bifidobacterium, Lactobacillus bulgaricus and Streptococcus thermophilus.

Bifidobacterium is a strict anaerobic bacterium and cannot be fermented alone. In the process of mixed fermentation, Streptococcus thermophilus first grows and reproduces, thus consuming oxygen in milk, creating an anaerobic environment, enabling Lactobacillus bulgaricus and Bifidobacterium to proliferate and ferment and produce beneficial metabolites. The yogurt fermented in this way not only has the nutritional value of ordinary yogurt, but also has the health care value of Bifidobacterium.

3. Mixed fermentation of Lactobacillus casei

The fermentation was carried out with Lactobacillus casei, Lactobacillus bulgaricus and Streptococcus thermophilus.

Lactobacillus casei has probiotic functions such as lowering cholesterol level, controlling diarrhea and relieving lactose intolerance. Because of the wide pH range, Lactobacillus casei can reach the gastrointestinal tract more smoothly and play the role of probiotics.

4. Mixed fermentation of Lactobacillus acidophilus

This fermentation is carried out with Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophilus.

Lactobacillus acidophilus can improve the activity of macrophages and lymphocytes, help digestion and maintain the acid-base balance of intestine.

5. Mixed fermentation of Lactobacillus plantarum

The fermentation was carried out by lactobacillus plantarum, lactobacillus bulgaricus and streptococcus thermophilus.

Lactic acid bacteria from plants are more suitable for China people's digestive system and can be used to ferment tofu or yogurt. Lactobacillus plantarum is mainly used for traditional food fermentation and is a healthy microbial organic food raw material. It can help digestion, relieve intestinal dysfunction and prevent bean allergy.

6. Mixed fermentation of Lactobacillus acidophilus and Bifidobacterium

This fermentation is based on the symbiotic relationship between Bifidobacterium and Lactobacillus acidophilus.

Lactobacillus acidophilus needs acetic acid, vitamins and folic acid as nutrients, while Bifidobacterium can not only produce acetic acid, but also synthesize vitamins such as vitamin B2 and folic acid to meet the needs of Lactobacillus acidophilus and promote the growth and proliferation of Lactobacillus acidophilus. Lactobacillus acidophilus grows rapidly in milk matrix with slight oxygen content, which can gradually reduce the redox potential in milk matrix, provide various substances that can be easily decomposed and utilized, and promote the growth of Bifidobacterium. At the same time, mixed culture can also accelerate the speed of acid production, shorten the coagulation time, and have better flavor.

7. Mixed fermentation of Lactobacillus acidophilus and Streptococcus casei

This kind of yogurt uses a certain relationship between the two kinds of bacteria to improve the speed of acid production and shorten the fermentation time, and uses the characteristics of the latter to produce butanedione, thus improving the flavor of the product and making the yogurt delicate in texture, sweet in acid and fragrant in sweetness.

The optimum fermentation conditions of the mixed bacteria are: the ratio of mixed bacteria is 1: 2, the fermentation temperature is 4 1℃, and the inoculation amount is 3-5%. The mixed fermentation of two kinds of bacteria can effectively make up for the lack of flavor of Lactobacillus acidophilus milk and enhance the palatability of yogurt. At the same time, there is a certain relationship between the two bacteria, which enhances the acid-producing ability and shortens the fermentation time.

The shelf life of yogurt made by Lactobacillus acidophilus and Streptococcus casei under the above optimum fermentation conditions is 7 hours, and a large number of live Lactobacillus acidophilus are retained, which has nutritional and health care functions.

8. Lactobacillus acidophilus and other strains

Lactobacillus bulgaricus and Streptococcus thermophilus are commonly used strains in yogurt production. Lactobacillus acidophilus and Enterococcus faecalis are normal flora in human intestine. They can not only tolerate gastric acid and bile acid, but also colonize the intestine.

The survival rates of Enterococcus faecalis mixed with gastric juice were 59% and 37%, respectively, while the survival rates of Lactobacillus bulgaricus and Streptococcus thermophilus were only 0.65%-0.05438+0%. However, the fermented dairy products produced only by Lactobacillus acidophilus are different from those produced by traditional starter cultures, which are difficult to be accepted by consumers. Fermented dairy products with different nutritional value and flavor can be produced by using yogurt strains, namely Streptococcus thermophilus and Lactobacillus bulgaricus, and the problems existing in traditional technology can be solved at the same time.

Expand knowledge: Is the more yogurt strains, the better?

Yogurt is rich in nutrition and plays an important role in enhancing human digestive function and promoting appetite. However, the number of strains in yogurt is not as high as possible. This is because the optimum fermentation conditions of different lactic acid bacteria are different. The more strains, the more difficult it is to unify the fermentation conditions, and the better the fermentation effect may not be.

Secondly, adding a variety of "probiotics" seems to be more "nutritious", but there is a competitive relationship between different strains, which will also affect its fermentation effect. Moreover, most probiotics die before reaching the stomach and cannot play a beneficial role.

Therefore, when purchasing yogurt in daily life, you don't have to care too much about the number of strains. It is enough to see Lactobacillus bulgaricus and Streptococcus thermophilus among the strains needed for fermented yogurt. In addition, it should be noted that the "total number of colonies" should meet the national standard, that is, 1000000CFU/g(mL/g (milliliter)). And try to choose yogurt that is refrigerated at around 4℃ and close to the production date.