Chitin from chicken bones and feet: reality or confusion? A brief analysis of the current situation

The search for inexpensive raw materials for chitin production has led to the exploration of various natural resources, including some less conventional ones, such as plants and waste from the processing of various animals. In this context, the production of chitin from chicken bones and feet has been reported, attracting attention as a cheap and widely available source in some regions. However, to the best of our knowledge, birds do not possess genes that encode chitin synthases, the enzymes responsible for chitin biosynthesis. Therefore, this study analyzes the results reported in related articles, especially their FTIR spectra, to assess when the obtained material can be identified as chitin. The analysis revealed that, in some cases, there is poor agreement between the signals in these spectra and the characteristic signals established for well-characterized chitins, while in others, the spectra exhibit signals with a high noise-to-signal ratio that limits their use for identification. Furthermore, the X-ray diffraction studies reported in some of these works provide scarce support to confirm the presence of chitin in these materials. A search of two specialized databases confirmed that, to date, no results have been reported for genes expressing chitin synthases in birds. Finally, some recommendations are offered for properly addressing the studies necessary for the unambiguous identification of these materials.