Regenerated chitin from insect sources and fabrication of their hydrogel films as an alternative from marine sources

The insect industry wherein insects are a novel food is growing, making insect chitin a byproduct. A leading scientist wondered if insects can be an alternative source of chitin from marine arthropods. Chitin can be used to fabricate hydrogels by using a DMAc/LiCl solvent. The current study aims to compare the physicochemical properties of extracted chitin and its hydrogels from different insects as Zophobas morio (ZM), grasshopper (GH), large brown Cicada nymph exoskeleton (CIEXO), and marine sources such as shrimp and crab. Fourier transform infrared spectroscopy, and X-ray diffraction analysis results demonstrated all extracted chitins and their hydrogels to be α-chitin. For both chemical extraction (1 M HCl at 20 °C for 24 h — 1 M NaOH at 90 °C for 5 h) and bleaching (2.5 v/v % sodium hypochlorite at 20 °C for 2 h), CIEXO exhibited the highest yields. Bleaching reduced the crystallinity and molecular weight but increased solubility in DMAc/LiCl over 95% for all samples. Hydrogels were fabricated from all samples; the hydrogelation process increased crystallinity and decreased chloride remanent for the bleaching process. Also, bleached hydrogels exhibited a bigger diameter and a regular surface. Thus, CIEXO-bleached hydrogel showed a viscoelastic behavior comparable to marine sources. CIEXO was shown to be a suitable substitute as a chitin source for hydrogel preparation.