How Taxonomic Relations Affect the Physicochemical Properties of Chitin

Abstract

Chitin specimens from 16 arthropod species (13 of Insecta and 3 of Arachnida) were isolated for the first time using the same method. Fourier Transform Infrared Spectrometry (FTIR), Thermogravimetric Analysis (TGA), X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and elemental analysis have been applied to determine how physicochemical properties of chitin specimens are affected by taxonomic relationship. The characterisation studies revealed that physicochemical nature of the chitin specimens differed greatly and were found partially specific to taxa. Significant differences in the surface morphologies of chitin specimens were observed even in the same order. However, the chitin contents were recorded to be specific to the order in the class Insecta. The highest chitin content was observed in Coleoptera (18.2–25.2 %) followed by Hemiptera (10.6–14.5 %), Odonata (9.5–10.1 %), Hymenoptera (7.8–9.3 %), Diptera (8.1 %), Blattodea (4.7 %). In addition, the crystalline index (CrI) values of chitin specimens from Coleoptera were found to be higher than the other orders in Insecta. This study revealed that the chitin contents and CrI values can be related to taxonomical relationships.