Gelatin is a large hydrophilic colloid with a molecular weight ranging from 15000 to 250000 Da. Usually, collagen is partially degraded from connective tissues such as animal skin, bone, muscle membrane, and muscle gland into white or light yellow, translucent, slightly glossy thin sheets or powder particles.
The water and inorganic salts in gelatin account for approximately 16%, and the protein content accounts for over 82%. Similar to maternal collagen, gelatin is also composed of 18 amino acids. Gelatin is soluble in hot water and insoluble in cold water, but can slowly absorb water, expand, and soften.