The "origin" of riding a princess in the world of mortals laughing

Du Fu wrote a poem about Tsinghua Palace, which has been widely circulated so far. It's about Tang Minghuang's allusion to let Yang Guifei eat fresh lychee. How did you keep litchi fresh in those days?

At that time, a fresh-keeping method was to use bamboo tubes to hold lychees. Put lychees in bamboo tubes made of cut bamboo. Then seal it with wax or wax to keep it fresh.

What is the principle of this? The fresh bamboo tube contains a certain amount of water, which can keep litchi moist, and the natural antibacterial ingredients contained in bamboo itself can also play a certain role in anti-corrosion.

At that time, it was said that considering the transportation difficulty of Qinling plank road, in order to further shorten the distance and time needed to keep fresh, the transportation difficulty was reduced. The craftsmen will plant the selected lychee trees in big wooden barrels and take good care of them. When the fruit is about to ripen, these litchi trees will leave for Chang 'an. When it is time to cross the Qinling Mountains, the lychees are just ripe. At this time, the lychees are picked and sealed in a bamboo tube, and they can be sent to Chang 'an in one day, so that Yang Guifei can taste fresh and sweet lychees.

The flesh of litchi is translucent and coagulated when fresh, and it tastes delicious, but it is not resistant to storage. Litchi is sweet, sour and hot. Enter the heart, spleen and liver meridians. It can stop hiccups and diarrhea, and is a good food therapy for those with intractable hiccups and diarrhea. At the same time, it has the effects of nourishing brain, keeping fit, stimulating appetite and invigorating spleen, and stimulating appetite. Because of sexual heat, eating too much is easy to get angry.

After talking about the preservation methods of ancient litchi, let's talk about the preservation methods of modern litchi: modified atmosphere preservation. Modified atmosphere storage is the best storage and preservation method for fruits and vegetables in the world.

It is characterized in that litchi is placed in the atmosphere and low-temperature environment with lower oxygen concentration than air and higher carbon dioxide concentration than air, so that the respiration rate of fruits and vegetables is reduced and the production of ethylene is reduced, thereby delaying the ripening and senescence process of litchi and achieving the purpose of keeping fresh.