Yogurt starter is a specific microorganism culture material used to make yogurt. Shuliy yogurt machine manufacturer reminds you that the role of starters in yogurt processing is very important. The starter is the basis and main reason for the acid and aroma production of yogurt products. The quality of yogurt mainly depends on the quality of the yogurt starter.
Lactic acid bacteria starter in making yogurt and its processing technology
1. Commonly used strains: Lactobacillus bulgaricus and Streptococcus thermophilus.
2. Preparation sequence of yogurt starter: mother starter-intermediate starter-working starter
3. Process conditions: the inoculation amount is 2.0% to 3.0%, and the strain ratio is 2: 1 to 1: 1. In the log phase inoculation, the main fermentation temperature is 42-45 ° C, and the time is 2.5-3.5h. Inoculation volume for low acid production should be more, and inoculation volume for high acid production should be less. Generally, the low inoculation amount is 0.5% to 1.0%, the high inoculation amount is more than 5.0%, and the most suitable is 2.0% to 3.0%.
Essential tips of yogurt fermentation
1. The temperature of yogurt fermentation is mainly between 42 and 45 ° C. This is also the optimal growth temperature for Lactobacillus bulgaricus and Streptococcus thermophilus.
2. Yogurt processors should pay attention to controlling three factors in production: inoculation amount, starter activity, and culture temperature.
3. Conditions for yogurt fermentation machine. After the sterilized milk is filled, it is quickly sent to the fermentation room. After fermentation at 42-45 ° C for 2.5 to 4 hours, the yogurt reaches a solidified state. At this time, the acidity of the yogurt is 0.7 to 0.8%, and the pH is lower than 4.6. After that, place the yogurt in cold storage at 2-6 ° C for 12 hours (to prevent excessive acidity, promote the production of aromatic substances, and increase the consistency of the yogurt).
4. The conditions for judging the endpoint of yogurt fermentation are: the state of the tissue is solidified, and there is no excessive whey separation.
5. What is the purpose of post-cooked fermentation of yogurt: to promote the production of aromatic substances in yogurt and increase the consistency of yogurt. Post-fermentation fermentation should also pay attention to the control of the yogurt’s tissue state and time to prevent over-acidity.