Aquatic products made of fish tissue collagen. Initially, it is the main fibrin that constitutes connective tissue. Its characteristic is that its thermal denaturation temperature is lower than that of terrestrial mammal collagen, so it is easy to gel. The melting point, freezing point and freezing force of its products are also relatively low. The types of fish glue are:
① Gelatin. It is made of skin and scales left over from making fish fillets, and there is no viscera, blood, meat, etc. The raw materials are washed, soaked in lime water, acid leached to remove calcium phosphate from fish scales, rinsed, neutralized, gelled, filtered, frozen, sliced and dried. Gelatin has high purity, high transparency, high viscosity and strong freezing ability. Mainly used for making culture medium, offset printing plate, photographic film, etc. , can also be used in the food industry.
② Coarse glue. Cleaning raw materials such as head, tail and bone mixed with blood, meat and viscera, heating with steam in a autoclave, filtering or high-speed centrifugal separation, removing impurities and fish oil, evaporating and concentrating to 50% concentration, and adding preservatives and spices. It does not freeze at room temperature and is convenient to use. It is an adhesive for wood, leather, etc. It is also a powder binder for making matches and grinding wheels.
③ swim bladder glue. After the swim bladder is washed with water to remove mucus and blood stains, the inner and outer membranes are peeled off, and the larger and thicker ones are respectively dried into pieces of glue; Smaller and thinner pieces are stacked together, rolled into a circle or a belt, and after drying, they are called round glue or tape glue. Yellowish, translucent, tough and slightly fishy. It is used as a clarifier for beer and other drinks and a thickener for fruit juice jam. In addition, high-quality large yellow croaker fillet glue, also known as fish belly, is a traditional seafood. Yellow-lipped fish gum is a valuable tonic. As a clarifier of alcohol, fish glue has been used to clarify beer for a long time, which can improve the coolness and freezing stability and shorten the maturity.
Application in book printing: Fish glue is the best adhesive material in animal glue and the most expensive one. It is made of scraps such as fish skin. Glue is made and used in the same way as other animal glue, but it is hardly used to make adhesive materials, because there are many substances obtained from fish in recent years, with high efficiency and wide application. You can buy it at the drugstore.