The decryption relationship between Milk and Milk running in Italian Coffee

How much do you know about coffee partners?

Barista

Do you understand milk?

I know that there are many friends who are eager to pull good flowers and practice embossing / pushing back / wheat ears / swans every day and night. Wait, the flower-pulling skill has been practiced countless times, maybe you have reached the stage of perfection, but you still can't pull the flowers well. Why? Maybe you ignore milk or you don't know anything about milk. Milk is as complex and changeable as coffee. No milk tastes the same. If you want to use milk in a cafe or even at home, it's definitely worth taking the time to discuss it.

The main body of milk is water that combines four substances: sugar, fat, protein and gray matter. Let's take a closer look at each substance.

Sugar

Milk is mainly lactose. Of course, it also includes glucose and galactose, but the content is so small that it can be ignored.

The essence of sugar is carbohydrates and a source of energy. When calves drink breast milk, they get digestible and long-lasting energy, which is achieved through lactose.

Lactose is not very sweet. If the sugar concentration of sucrose is 1.0, lactose is only 0.16. The sweetness is five times worse. This means that you have to add or remove a lot of lactose in order to feel the change in sweetness in the milk. The sweetness of lactose is much softer than sucrose, round, smooth, not greasy and heartburn.

An interesting fact is that the sweetness of lactose (including other sugars) varies with temperature.

Fat

Milk fat refers to the fatty substance in milk. What you see in the advertisement, the so-called skim milk, semi-skim milk, low-fat milk, fat-free milk, etc., all remove the milk fat part of the milk.

The structure of milk fat is complex, which is a mixture of triglyceride, glycerol butyrate and glycerol palmitate. Triglycerides are compounds formed from various fatty acids and esters, a little dizzy, OK, so to put it this way, triglycerides are less dense than water, and 65% of them are saturated fatty acids, including palmitic acid, myristic acid and cocoa butter. Another 35% of unsaturated fatty acids, including oleic acid and linoleic acid. These fatty acids are bound together called fat balls, which are 14 microns in size, which is definitely high molecular weight fat. Such a large molecular weight means that it is insoluble in water and can only be suspended in milk. Homogenized milk breaks the fat balls and distributes them evenly in the milk. In homogeneous milk, you can still find heterogeneous milk in the thin layer of the surface.

Fat gives a sense of weight in the mouth, of course, the sense of weight in the mouth caused by protein and sugar can not be ignored, but in milk, fat is the main force. Whole milk is full, thick and luxurious, while skim milk is usually thinner and unsatisfying. Food scientists around the world have been developing and simulating foods that are thick with fat, but they have been draining water from bamboo baskets for many years. How wide are you to remove this oily, mouth-filled, extremely satisfying fat? Accept her!

Fat (unfortunately?) It can also reduce the capture of coffee flavor by taste buds. Considering that black coffee is a solution of water and coffee flavor molecules, the molecules in this solution flow freely, and nothing can prevent the molecules from coming into contact with the taste buds. But the addition of milk fat changes the situation. Cream fat molecules can easily stick to other molecules. Your taste buds can only capture the molecules that come into contact with them, and the rest can only provide a basic taste in your mouth.

There are similar examples, such as eating or drinking fatty food or drink (such as milk), which can reduce the burning sensation. Capsaicin dissolves in fat.

Protein

Milk protein is unique and can only be obtained in mammal breast milk. For coffee drinks, the main role of protein is to help produce and stabilize foam. Wrap the air and milk by forming a protein film to keep the foam bubbles from bursting. One of the secondary effects of milk protein is to bring out a slight aroma of caramel, like the heated milk you usually drink.

76-86% of milk protein is composed of casein microclusters. Casein is a kind of protein, which is only found in mammal breast milk. Microclusters are the chemical names of macromolecules that bind together in solution. It is casein microclusters that allow insoluble protein molecules to flow freely.

The rest of the milk protein is mainly whey or whey protein. Bovine β-lactoglobulin is the most common whey protein that helps us foam, and the surface of these proteins usually absorbs water. They are unfolded by rolling and heating, making the hydrophobic part of the protein appear. These hydrophobic parts then glue the bubbles and reduce the surface tension to stabilize the foam.

Gray matter

The purpose of nature in producing milk is to make calves thrive. This means that a glass of milk has many benefits. Gray matter is what the dairy industry uses to name vitamins, minerals and biological enzymes.

Milk contains all water-soluble vitamins, B1, B2, B3, B5, B6, B12, C and folic acid. It also includes fat-soluble vitamins, Agraine Dpeng Epene K. Low-fat milk contains less vitamin A, which is generally added to reach the full-fat level.

Minerals include calcium, magnesium, phosphorus, potassium, selenium and zinc

It also contains a large number of enzymes, some of which degrade fats and proteins (reducing shelf life) and some that are antibacterial. Enzymes have no effect on the taste, of course, there are many enzymes that we do not know, only in the future study to further explore.