The main components of milk are protein, fat, lactose, and various minerals and vitamins. It is especially rich in calcium and phosphorus; a glass of milk (about 250 ml) contains half of the daily human requirement for calcium. However, if people do not pay attention to scientific cooking and drinking methods when consuming milk, its nutritional value will be greatly diminished. So, what mistakes do people make when drinking milk? Boiling milk for a long time at high temperatures: Milk is a heat-sensitive substance. When the temperature reaches 60℃～62℃, the protein particles in the milk will dehydrate, turn into a gel state, and subsequently precipitate. At the same time, the highly unstable acidic calcium phosphate in the milk will also turn into neutral calcium phosphate and form a precipitate. If the heating temperature reaches around 100℃, the lactose in the milk will begin to caramelize and turn brown, and gradually decompose to produce lactic acid and a small amount of formaldehyde. Boiling milk for a long time also results in significant loss of vitamins. Therefore, milk should only be heated until it just comes to a boil and then taken off the heat; it should not be boiled for a long time. Adding sugar while cooking: Lysine in milk and sugar undergo a Maillard reaction at high temperatures, producing a toxic substance—fructoselysine, which is harmful to human health and especially so for children. If you want sweet milk, you should add the sugar after the milk has been cooked and has slightly cooled. Similarly, milk should not be cooked with chocolate, because chocolate is rich in oxalic acid. When cooked and eaten together, the calcium in the milk will bind with the oxalic acid to form calcium oxalate, which is not easily absorbed. It can also cause symptoms like diarrhea. Therefore, the two should be eaten separately.
Drinking milk on an empty stomach: When the stomach is empty, gastrointestinal motility is faster, and milk stays in the gastrointestinal tract for a short time. It cannot make full contact with digestive enzymes, and its nutrients are "hurriedly" excreted into the large intestine before they can be digested, thus not being fully absorbed and utilized. The correct way to drink milk is to consume it with starchy foods such as steamed buns, bread, or pastries at the same time. This allows the protein, calcium, and other nutrients in the milk to stay in the gastrointestinal tract for a longer period under the action of the starch, enabling full absorption and utilization of the nutrients. Mixing with acidic foods: After milk enters the gastrointestinal tract, it is first acted upon by pepsin in the gastric juice and trypsin, which bind with the protein in the milk, before entering the small intestine. If acidic drinks or fruits are consumed at this time, the protein in the milk will curdle with the fruit acid and vitamin C, forming clumps. This not only affects digestion and absorption but can also lead to symptoms such as diarrhea, abdominal pain, and bloating. Improper storage: Some people like to chill (freeze) milk in the summer. When the temperature of the chilled milk is below zero degrees Celsius, the fat and protein in it will separate, and the casein will coagulate into a powder-like substance, causing its flavor to be significantly weakened and its nutrients to be less easily absorbed. If a person frequently drinks chilled milk, it can also easily promote the recurrence of gastrointestinal diseases such as ulcers, cholecystitis, and enteritis. Others also like to store leftover milk in a thermos. Doing so creates a nutritious incubator for bacteria from the milk or the air in the upper part of the thermos, which will multiply rapidly. Within a few hours, the milk will sour and spoil, and vitamins B and C will also be largely lost. Therefore, it is best to drink freshly cooked milk after it has slightly cooled.