Why are fruits and vegetables sweet during the first frost and solar terms?

As the saying goes, "it is better to make up the first frost a year." The first frost is the initial stage of the transition from autumn to winter. Putting some autumn fertilizer at this time can help the human body resist the cold in winter. As a veteran foodie, there is no reason not to seize the first first frost solar term and enjoy it.

"Summer sorghum, Bailu Valley, first frost radish", "first frost orange is sweet". Once frosted, grapes, oranges and other fruits will be sweeter, and even radishes will taste like My Sweetie. Hairy crab sauce is full of yellow overflow, and all kinds of seafood have reached the most fertile period. The best beef is also called first frost beef. The welfare of these foodies sounds related to the first frost. Is it also related to meteorological factors?

The first frost comes to pull out radish.

Frost is spread all over vegetation and rocks, commonly known as frosting. Vegetables covered with frost, such as spinach, wax gourd and radish, taste a little sweet. What is the reason?

Strictly speaking, the word "first frost" is illogical. We have seen rain and snow, but no one has seen frost. In fact, the frost did not come down, but formed in the air near the ground.

On sunny days, breezes or windless nights in cold seasons, the ground temperature is extremely low, and the water vapor near the ground condenses into small ice crystals and adheres to the ground or plants. This is the frost-frost formation process, which is an exothermic process.

Frozen cabbage

What's wrong with frosted vegetables? Are they sweet? It turns out that vegetable water such as wax gourd, radish and grapes contains starch, which is not sweet in itself and is not easy to dissolve in water. But after the first frost, the starch in wax gourd, radish and grape will be hydrolyzed into maltose under the catalysis of amylase, and maltose will be converted into glucose under the action of maltase. Glucose is sweet and soluble in water, so vegetables and fruits will become sweet. Why do these changes happen to plants? The reason is-because they are afraid of the cold.

Frosted persimmon

In some parts of China, people eat persimmons at the first frost. Persimmons generally mature completely before and after the first frost, which is also the reason why persimmons are thin and fresh, delicious and sweet. In some areas of our country, there is a saying that eating persimmons in the first frost does not cause runny nose. Experts explained that the real reason is that persimmons generally mature completely before and after the first frost. At this time, persimmon has thin skin and thick meat, delicious taste and high nutritional value. According to the viewpoint of TCM health preservation, the first frost is late autumn, which is dry and easy to cough. At this time, the fully mature persimmon is sweet and cold, which can moisten the lungs and protect the stomach, and clear the fire.

Frost disaster is mainly caused by water freezing in plants. When starch becomes glucose and dissolves in water, the water in plants is not easy to freeze, and the cell fluid is not easy to be destroyed, so it will not freeze. If you don't believe me, you can do a small experiment: in the cold winter, put water in one plate, sugar water in the other plate and put it in the yard. Soon, you can see that the plate with clear water has frozen, but the plate with sugar water has not frozen. The frost on vegetables will evaporate after the temperature rises, and the leaves of vegetables will wilt slightly, so the frosted leaves of vegetables are soft, which is also called "frosted vegetables".

The first frost solar term is also a good time to eat seafood. Crabs are fat, oysters are nutritious, and lobsters are delicious ... Once the first frost has passed, sea cucumbers gradually wake up from their sleep and start to go out for food. At this time, the meat quality of sea cucumber is the fattest, which is the best time to salvage in a year, and it is also the time to replenish sea cucumber.

Finally, talk about the first frost beef. The first frost beef has nothing to do with the weather. It is the best beef, because the oil is like frost, so it is called the first frost beef. The distribution of oil is similar to that of ground beef. The first frost solar term is a good opportunity to make up for it, and it is also the most delicious time for all kinds of fruits and vegetables, so foodies should pay close attention to it.

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