How milk turns into yogurt: scientific analysis and production methods
As a healthy and delicious dairy product, yogurt has been favored by consumers in recent years. So, how does milk become yogurt? This article will analyze this process in detail for you and provide relevant data and production methods.
1. The scientific principle of turning milk into yogurt
The making process of yogurt is essentially a fermentation process, which mainly converts lactose in milk into lactic acid through the action of lactic acid bacteria. Here are the key steps:
| step | effect | temperature | time |
|---|---|---|---|
| 1. Sterilization | Eliminate harmful microorganisms | 85-90°C | 15-30 minutes |
| 2. Cool down | Create a suitable environment for lactic acid bacteria | 40-45°C | about 10 minutes |
| 3. Vaccination | Add lactic acid bacteria starter | 40-45°C | immediately |
| 4. Fermentation | Lactose is converted into lactic acid | 40-45°C | 4-8 hours |
| 5. Refrigerate | Inhibit fermentation and stabilize quality | Below 4°C | At least 2 hours |
2. Main fermentation strains and their functions
| strain name | Latin name | Optimum temperature | Main functions |
|---|---|---|---|
| Lactobacillus bulgaricus | Lactobacillus bulgaricus | 40-45°C | Produces acid and creates taste |
| Streptococcus thermophilus | Streptococcus thermophilus | 40-45°C | Produce acid and produce aroma substances |
| Bifidobacteria | Bifidobacterium | 37-41°C | Prebiotic function |
3. How to make homemade yogurt at home
1.Prepare materials: 500ml of fresh milk, 50g of commercially available yogurt (containing active bacteria) or 1 small packet of yogurt starter
2.Production steps:
| step | Operating Instructions | Things to note |
|---|---|---|
| Sterilization | Boil the milk and keep on low heat for 5 minutes | Use a thick-bottomed pot to prevent scorching at the bottom |
| cool down | Cool to 40-45°C (warm to the touch but not hot) | Confirm with thermometer |
| Vaccination | Add yogurt or starter and mix well | Make sure utensils are clean |
| fermentation | Place in an insulated container and keep at about 40°C for 6-8 hours | avoid shock |
| refrigeration | After fermentation is completed, refrigerate for more than 2 hours | Can be stored for 3-5 days |
4. Comparison of nutritional value of yogurt
| Nutritional information | Milk(100g) | Yogurt (100g) | Range of change |
|---|---|---|---|
| protein | 3.3g | 3.5-4.0g | ↑6-21% |
| calcium | 120mg | 120-150mg | ↑0-25% |
| lactose | 4.8g | 3.0-4.0g | ↓17-38% |
| Vitamin B12 | 0.4μg | 0.5-0.7μg | ↑25-75% |
5. Frequently Asked Questions
1.Why doesn't my yogurt set?Possible reasons: inappropriate temperature, insufficient fermentation time, bacterial inactivation or contamination.
2.How long can homemade yogurt be kept?It can generally be stored for 3-5 days under refrigerated conditions and is recommended to be consumed as soon as possible.
3.Why does yogurt have yellow liquid?This is whey protein, which is normal and can be stirred before consumption.
4.Can I drink yogurt if I am lactose intolerant?Yes, because the fermentation process has broken down most of the lactose.
6. Tips for making yogurt
1. Use fresh whole milk for a thicker taste
2. Avoid opening the lid frequently to check during the fermentation process.
3. The key to success is maintaining a constant fermentation temperature
4. To make Greek yogurt, strain it through gauze to remove some of the whey.
Through the above content, we understand the whole process of turning milk into yogurt and related scientific knowledge. Whether it is industrial production or home-made, mastering the correct principles and methods can help us make delicious and healthy yogurt.
check the details
check the details
en
