Condensed milk is a kind of dairy products, which is a beverage made of fresh milk or goat milk after disinfection and concentration. It is characterized by long-term preservation. It is usually made by removing most of the moisture in fresh milk by vacuum concentration or other methods, concentrating it to about 25% ~ 40% of the original volume of dairy products, and then adding 40% sucrose to cans.

Tangyuan, also known as Yuanxiao, Tangtuan and Piao Zi Yuan, is one of the representatives of traditional snacks in China, and it is a spherical food made of glutinous rice flour. There are usually fillings, which are cooked and eaten with soup. At the same time, it is also the most distinctive food of the Lantern Festival with a long history.

Tangyuan originated in the Song Dynasty. At that time, Mingzhou (now Ningbo City, Zhejiang Province) began to eat a novel food, which was filled with black sesame seeds and lard, with a little sugar, and wrapped in glutinous rice flour. After cooking, it tastes sweet, delicious and interesting. Because this kind of dumpling is floating and heavy when cooked in a pot, it was originally called "floating Zi Yuan", and was later renamed as dumpling in some areas.

Eating dumplings is a traditional custom of China people, especially in the south of the Yangtze River. There is a folk saying that "eating glutinous rice balls is one year older". Chen Zhisui's poem "Tangyuan" said: "Every winter solstice, everyone cooks, one year old, do you know?" There is a saying in Ningbo: "Every family in Ningbo makes glutinous rice balls, and contentment is always happy." Hu also wrote a poem: "Xiangze glutinous rice is used as dumplings, and boiling water is rich and salty." The entrance is sweet and smooth, and the family is happy and intoxicated.