Little knowledge of solar terms: Why are apples sweet in the first frost?

The first frost is one of the twenty-four solar terms and the last solar term in autumn. It is very important to keep healthy during the first frost. During the first frost solar term, many people will eat first frost beef and first frost apples to keep healthy. Then do you know why the first frost apples are sweet? Come and have a look with me.

Why is the first frost apple sweet?

Why are apples sweeter after frosting? That's because the first frost will appear when the temperature is very low. In order to resist the cold, apples will convert starch into sugar, so that the cell fluid in apples is not easily destroyed, nor is it easily destroyed by frost. This is a way for plants to protect themselves and adapt to environmental changes.

After the first frost, the starch in fruits and vegetables is hydrolyzed into maltase by amylase in plants, and then turned into glucose by maltose. Glucose is soluble in water and tastes sweet, so apples and vegetables taste sweet.

The origin of solar terms

Every year around Gregorian calendar 10 year 10, when the sun reaches the longitude of 2 10 degrees, it is the first frost in the 24 solar terms. The first frost is the last solar term in autumn, which is the transition from autumn to winter. There is a lot of heat dissipation on the ground in autumn night, and the temperature suddenly drops below 0 degrees.

Water vapor in the air directly condenses on the ground or plants to form fine ice needles, and some become hexagonal frost flowers, which are white and loose in structure.

Key points of health care

In the north of China, every time the temperature drops in the first frost, the water vapor in the air will adhere to the surface of the ground and condense into frost when it meets the objects on the ground. In the morning, before the sun comes out, we can often see the rime wrapped in dry branches. This is nature reminding us that winter is coming. In southern China, after this solar term, it is entering a busy period of autumn harvest and autumn planting.

There are "three phases" about the first frost in the seventy-two phases. "The first jackals sacrifice animals" means that jackals should store food for the winter from the first frost; "Second, the vegetation is yellow", at this time, the vegetation is yellow and the leaves are all over the ground; "Three stings change salt", and animals ready to hibernate began to hide in caves for the winter. At this time, nature is in the transition stage to winter, so we humans should put aside the "autumn freeze" and make some preparations for a healthy winter.

Late autumn is a period of high incidence of respiratory diseases. Eating more pears, apples, olives, gingko, onions, mustard greens, radishes and other foods, rubbing the sides of Xiang Ying's nose and practicing the word "hiss" will help us prevent respiratory diseases.

The cold weather, improper local body warmth or increased human metabolism to adapt to the cold stimulus increase the incidence of chronic stomach diseases and "old cold legs". Especially people with a history of digestive tract ulcer should pay special attention to self-maintenance, adhere to the guidance of doctors and avoid taking food and drugs that are irritating to gastrointestinal mucosa.

Frost leaves are redder than February flowers. After the first frost, maple, cotinus coggygria and other trees began to turn red and yellow, all over the mountains, very spectacular. When you go out to climb mountains and enjoy the beautiful scenery, you must keep warm, especially protect your knees, and you must not exercise excessively. When the knee joint encounters cold stimulation, blood vessels contract and blood circulation becomes worse, which often aggravates the pain. Therefore, pay attention to keep warm in cold weather and wear knee pads when necessary. When the elderly exercise, it is not advisable to bend their knees for a long time to reduce the load on the knee joint as much as possible.

The above conclusion is about the first frost. I wonder if it will help everyone?