1. thicken the juice. Thickening juice is a technological process that uses the principle of starch gelatinization to disperse starch particles in water to form starch solution, so as to increase the consistency of soup. Most of the general braised dishes use thickening juice, such as braised fish and braised sea cucumber. When collecting the juice, we should pay attention to the timing of adding the juice, and add it when the soup in the pot is boiling; Second, we should master the amount of starch juice, which should be flexibly mastered according to the selection of materials and the requirements of cooking.

2, sugar juice. Sugar juice harvesting is a process of thickening soup with sugar. Its principle is to use sucrose to increase the concentration of solution, and at the same time, sucrose decomposes during heating, and the broken hydrogen bond combines with water, thus achieving the purpose of juice collection. Most of them are suitable for cooking with sweet and sour taste, such as braised pork, sweet and sour pork ribs and so on.

3. There are still some materials that can be harvested by self-invitation. Juice-harvesting from Zizaili is mainly suitable for raw materials rich in collagen, which is a process in which collagen is decomposed and dissolved into soup after a long period of stewing, so that the soup becomes thick. The principle of juice collection is that collagen is dispersed and dissolved in the soup after heating, so as to improve the concentration of the soup and achieve the purpose of juice collection. Its representative dishes are braised elbow, dry-roasted rock carp and so on.