What happened to the bitter milk

Milk as a nutritious food rich in protein and calcium, many people love to drink milk, but some friends find themselves buying milk has been bitter, so how is the milk bitter?

What happened to the milk bitter

Protein decomposition caused by

After the milk is sterilized by ultra-high temperature, the enzyme is blunted and inactivated. But storage and transportation if the impact, high temperature exposure and other external stimuli, inactivated heat-resistant protease may be activated, so that part of the milk protein decomposition, producing some bitter, peptones, amino acids, etc., so that the milk is bitter. You do not have to worry about this situation, bitter substances are not toxic to humans, spit out the bitter milk and rinse your mouth.

Caused by casein precipitation

Milk contains 3% to 3.5% protein, of which casein accounts for 80% to 82% of the total protein. Casein is actually calcium caseinate - calcium phosphate complex, which is present in cow's milk in the state of colloidal suspension, while casein colloid also contains magnesium ions. When the milk is exposed to light or a longer period of time at high temperatures (such as storage or transportation above 25 ℃), the acidity in the milk will gradually rise, when the pH value of casein reaches 4.6, casein will begin to precipitate, and then the casein calcium and magnesium ions are free, and the original chloride ions in the milk to form a bitter substance calcium chloride (CaCl2), magnesium chloride (MgCl2) and other substances This causes the milk to become bitter.

Can you drink bitter milk?

You can still drink milk after it becomes bitter. The premise is that the milk has not expired, the milk bag is not bulging, there is no bad smell, the color does not look changed, and there is no stratification or flocculation after heating.

How to keep milk well

1. Fresh milk should be placed in a cool place immediately, preferably in the refrigerator. 2, Do not expose the milk to sunlight or light, sunlight and light will destroy several vitamins in the milk and also make it lose its aroma. 3, milk in the refrigerator, the cap should be covered, so as to avoid other kinds of odor string into the milk. 4, milk poured into cups, teapots and other containers, such as not finished, should be covered and put back in the refrigerator, do not pour back into the original bottle. 5, too cold on the milk also has adverse effects. When the milk is frozen into ice, its quality will be damaged. Therefore, the milk should not be frozen, put it in the refrigerator to chill.

Tips

Pay attention to the date of manufacture before buying whole cartons and cartons of milk, try to buy freshly produced products and drink it as soon as possible to avoid long storage.