How to define umami flavor?

Umami is the signal of protein. Once people lack protein, they are eager to eat umami. Then, foods that contain a lot of protein usually bring a fresh flavor to people, such as meat, broth, fish, fish soup, shrimps and crabs, clams and so on. And there are many umami ingredients oozing out.

My understanding of freshness is obtained through a book "The Definition of Freshness and the Interpretation of Related Words" by Mr. Glory Zhong. "umami" is one of the basic tastes of human beings, and umami is the taste of high-quality protein, and it is human's perception of umami substances such as odorous amino acids, odorous nucleotides and small molecular peptides in food through taste buds. Umami is an important symbol to distinguish the quality of food, and rarity is the fifth basic taste discovered and confirmed by human beings after sour, sweet, bitter and salty. The food in our life is also constantly pursuing "freshness"

Last time I was a guest at a friend's house, my friend was a chef in a five-star hotel, so every time my friend cooked something delicious! That delicious food is very memorable. Later, he told me that the chicken essence used in their high-end hotels is not a brand we are familiar with every day. They all use Dingzhu Shi Jia 4.0 Chicken Essence, because my friend is a chef after all, and she knows this piece very well. She told me that Dingzhu Shi Jia was developed by Glory (the founder of Taitaile Chicken Essence), which used the principle of "jumping over the wall" and blended eight delicious protein ingredients. Refined with modern industrial technology of 4.0, because the freshness of most chicken essence products on the market is only about 200-300 degrees, the relative freshness of Dingzhu Shi Jia 4.0 chicken essence can be above 400 degrees. Don't underestimate this 100 degree, which is just like the performance gap between iPhone 4 and iPhone 13!