What is the structure of gelatin (explain how it is bonded together, the type of bonds, etc.)?

The common properties of polymeric substances can be found at gelatines. The  physico-mechanical properties of gelatin depends on the molecular structures that can vary from globular structures to fibrillar structures.

The gelatin has the following distinct properties, such that:

- the gelatin macromolecules contain basic functional groups and acidic functional groups

- gelating interacts with water, the sorption capacity of gelatin solidly depending on pH

- gelatin can form, at low temperatures, the triple-stranded helical structure

If heated, gelatin changes its physico-chemical properties, hence, at temperatures over 140^o C, because of chemical bonds between gelatin macromolecules, gelatin becomes insoluble in hot saturated urea solutions.

Hence, gelatin's behaviour depends on the conformation of its macromolecules, that can be coiled or helical, but in absence of water, gelatin acts like a brittle material, without any reference to its molecular structure.