Milk is one of the most nutritious and valuable products, and not only cow’s milk but also goat’s, sheep’s, and even camel’s milk. But if its usefulness is not in doubt, then the question of why it is white interests both children and adults. So, why is milk white?
There are over 5,000 species of mammals on Earth that give milk. Its taste and composition may vary significantly, but the color is invariably the same.
Why is milk white and what does it do?
To understand this question, it is desirable, first, to understand what a dairy product is. Milk is a nutrient fluid that is produced by the mammalian mammary glands. Its primary function is to feed babies, including human babies.
At an early age, babies cannot digest solid food, so milk is the only substance their bodies can digest.
In most cases, milk is produced only during the period of carrying and feeding, but some animals can give it all the time.
Cow’s milk is the most popular among people because it is highly nutritious and has many useful substances. To get it, specially bred breeds of cattle, give a large and good milk yield.
What is milk made of?
Milk is thought to be similar in composition to the mother’s blood that nourishes babies before they are born. It contains over 50 macronutrients and micronutrients that make it healthy, dense and viscous.
Magnesium, sodium, chlorine, potassium, phosphorus, iodine, and zinc are present in all dairy products. The most important element in milk is calcium. It provides easy digestibility of the product and helps to strengthen the skeletal bones.
Why is milk white?
But what makes milk white? A complex protein called casein handles its color. In cow’s milk, it amounts to 87% of all proteins, while in women’s milk it is 40%.
This substance is present in the product as a calcium salt (calcium caseinate). It contains practically all the amino acids necessary for human life.
Interestingly, of these 20 amino acids, 8 are not produced by the human body. Therefore, they must enter the blood through food.
In milk, casein creates spherical particles in milk, called micelles. They are so light that they do not precipitate but float in the liquid and give it a white color.
If the casein is extracted from milk and dried, it turns out to be a white powder that is tasteless and odorless. Casein is even used to make casein paint for painting on wood, canvas, or paper, thanks to its milky color.
What are the benefits of casein?
As well as colouring milk white, casein has many health benefits. It is a rich source of phosphorus and calcium. It dissolves slowly when it enters the stomach, so milk is easier to digest. It is casein that gives dairy products their high nutritional value.
Because of its balanced composition and essential acids, it is often included in athletes’ diets, especially during long breaks between workouts.
Is milk any other color?
Milk is only white, but in some animals, it can appear in different colors. The whitest milk is produced by the mammary glands of rabbits. It contains 15% of the casein. The second place is given to whale milk, which contains 12% protein, and the third place to deer milk (10%).
Cow’s milk only has about 5% casein, and women’s milk has even less – about 1.4%. But this amount is enough.
The color of the milk can be influenced by the nutrition of the animals. In particular, if a cow is constantly fed carrots, she will give a product with a yellowish hue.
If there are many buttercups plants growing on the pasture, the cow’s milk will be pink.