Spring is in full bloom, and all kinds of delicious fruits are on the market one after another. I recently opened a new way to play, the milk and various fruits mixed into a nutritious and beautiful milkshake. Every day with different flavors of milkshake, feel all day full of energy!

On a bright morning, I came to the office.

It was just about time to bury my head in the sand

It was surprising to find

that the papaya milkshake that I had made in the morning had curdled into a "tofu dregs"!

Though the shape has changed

But thinking about the sweet flavor of papaya milk

I had the courage to taste it

But it was bitter

What's going on here?

Keyword: casein

These questions actually start with the proteins in milk.

The key ingredient in milk is protein, the largest proportion of which is casein, which makes up 80 percent of milk's total protein.

The casein family is mainly composed of αs-, β-, κ- three brothers, they are in the help of calcium ions and phosphate, united together, in the form of casein particles present in milk. The αs-casein and β-casein, which hate water molecules, form the inner core (subunits), while the κ-casein, which has a good relationship with water molecules, forms a "shell" on the outside.

If the individual casein micelles and the large amount of water are "at peace," the milk appears to be homogeneous. But when encountered some unfavorable conditions, destabilized the casein glue particles, milk casein and water "go their separate ways", there will be protein "holding" precipitation phenomenon.

Some unfavorable conditions, such as papaya!

Keywords: protease

Milk and papaya, why become "doudoune moncler?

This is because of the papaya in a protease in the "trouble".

Normal circumstances, the milk itself casein gelatin particles are very stable. Fresh papaya contains papain, a papain enzyme, which can form the milk jelly protease, also known as "rennet". It cuts off κ-casein from specific places and turns it into paracasein.

The casein particles, which have lost their protective outer shell, gradually coalesce because of hydrophobic interactions. Eventually, with the help of calcium ions, αs-, β-, and par-κ-casein **** together form an insoluble frozen state, and a "beanflower"-like precipitate appears.

While this process affects the appearance and taste, it does not prevent the digestion and absorption of milk proteins. Because there is more powerful stomach acid waiting! The acidity of stomach acid is much higher than that of fruit juice, so as long as you drink milk into the stomach, sooner or later, you will have to become "doudoune moncler pas cher" state.

Milk why become bitter

Milk with papaya, will produce a bitter flavor, in fact, or protease to engage in "mischief".

Papaya into the milk, if not eaten immediately, but after half an hour to eat, then because these enzymes will quickly break down the milk protein, generating a number of peptides with a bitter taste, will make the taste of milk become difficult to swallow. At the same time, the milk may also form a curdled form - the reason for curdling has just been mentioned.

In fact, not only papaya, in kiwifruit, pineapple, mango and other fruits, also contains a high level of protease, especially less ripe kiwifruit, the enzyme activity is quite considerable.

Many people eat raw kiwi and pineapple, there is a "mouth" feeling, but also because the enzyme breaks down the protein of the oral mucosa caused by the pain.

Milk harmony with the principle

In the matter of partnering with milk, fruit can be said to be in a state of flux. However, after understanding the characteristics of milk proteins, we can find ways to make them live in harmony, the following principles are important:

01 Kill or inhibit enzyme activity

such as steaming the fruit cooked, or and milk together with some ice to cool down.

02 Don't chop the fruit too much when you put it in the milk

Large chunks of fruit will make less contact between the enzymes and the milk proteins. Then eat it quickly to reduce the chance of enzyme action and you won't have a problem with the bitter flavor.

So how do you make "papaya milk"? It is very simple, just need to first steam the papaya, or microwave heating to the center temperature of about 70 degrees Celsius, the protease to destroy, you can rest assured and milk with. For example, when papaya stewed milk, first stewed papaya, after the milk, the taste is still very good, neither bitter, nor precipitation.

As for fruit shakes or fruit smoothies, just keep the pulp at a low temperature, or refrigerate the fruit and milk first, then add some ice -- the low temperature can temporarily inhibit enzyme activity.

But the protease will still be active as soon as the temperature rises. So after beating, do your best while the icy feeling is still there