Yogurt contains viable bacteria beneficial to the intestine, and it is best to keep it at 0-4℃. Too high temperature or freezing will destroy lactic acid bacteria, which is not conducive to intestinal absorption. So it's best not to freeze, but to refrigerate.
The main component of yogurt is active lactic acid bacteria, which can prevent protein from fermenting and reduce intestinal gas production, thus alleviating symptoms such as abdominal distension and indigestion. Yogurt containing active lactic acid bacteria has a short shelf life, usually about two weeks, and must be stored at 2℃ ~ 6℃, otherwise it will go bad easily.
2. What chemical reaction happened after yogurt was put into the frozen layer?
In the process of repeated freezing and thawing, due to the uneven mixing of oil and water, lactose and water will precipitate and crystallize, resulting in a sandy taste. In other words, the structure of yogurt is unstable during freezing and thawing without adding stabilizers such as emulsifiers.
When frozen yogurt is taken out of the refrigerator, eat it as soon as possible. Even if you want to thaw and soften, please thaw in the refrigerator at 4℃, not at room temperature. At room temperature, bacteria grow super fast, which is easy to cause food diseases.
1, lactose part
There are two forms of lactose, α and β. β -lactose monohydrate is super easy to crystallize, so food factories will add some emulsifiers to solve the crystallization problem of β -lactose However, the crystallization temperature of α -lactose monohydrate is very low, below 0℃, and the storage temperature of ordinary yogurt is 4℃. In the process of freezing and thawing yogurt, α -lactose monohydrate crystallizes and tastes like sand.
2. Water part
The faster the food is frozen (for example, using liquid nitrogen), the smaller the water crystals will be. On the contrary, if the food is frozen slowly, the crystal will be bigger. If it is an ordinary refrigerator, the freezing speed is very slow. Without using stabilizers and emulsifiers to stabilize the water-oil structure, the water activity of yogurt is super high, and it is easy to separate out water, and then it is frozen into large crystals and tastes like sand.
Extended data
Yogurt is suitable for people:
Suitable for people with weakness, deficiency of qi and blood, malnutrition and constipation; Suitable for patients with hypercholesterolemia, arteriosclerosis, coronary heart disease and fatty liver; Is suitable for cancer patients, especially digestive tract cancer patients; Suitable for people with dry skin, and can also be used as beauty food; Women who drink yogurt in moderation for a long time will have moist, delicate and shiny skin.
Yogurt is not suitable for people;
People with hyperacidity should not eat more; Patients after gastrointestinal surgery, patients with diarrhea or other intestinal diseases are not suitable for drinking yogurt.
References:
Baidu encyclopedia-yoghourt