Functional and microstructural characteristics of chitin extracted from field cricket, house cricket, and black soldier fly cocoons

 Chitin from crustaceans is used in food, pharmaceutical, medical, agricultural and environmental sectors. Edible insects’ chitin is an untapped resource since edible insects have a high biodiversity and considerable amounts of chitin. Therefore, this study aimed at characterizing the functional properties and microstructure of chitin extracted from House cricket (Acheta domesticus), field cricket (Gryllus bimaculatus) and black soldier fly cocoons (Hermetica illucens) and compared with shrimp chitin (commercial). Chitin was chemically extracted and the functional groups were determined by Fourier Transform Infrared Spectroscopy (FTIR). Solubility, emulsion capacity, Water Holding Capacity, Fat Binding Capacity, degree of deacetylation and purity of the extracted chitin were also determined. Based on the FTIR spectra the extracted chitin showed the characteristic functional groups i.e. O–H stretch, C=O stretch, N–H bend, CH2 ending and CH3 deformation, C–N stretch and C–O–C stretch. Chitin extracted from Gryllus bimaculatus recorded the highest values in fat absorption capacity (780.14%), emulsion capacity (65.67%) and emulsion stability (65.67%). Chitin extracted from, Acheta domesticus was more soluble in water as compared to the commercial chitin. The highest level of deacetylation was reported in Hermetia illucens chitin (66.2%) while Acheta domesticus chitin had the least value (47.1%). The commercial chitin and Gryllus bimaculatus had the highest values for purity followed by Hermetia illucens. The microstructure images showed presence of pores and fibers in all the chitin samples. In conclusion, the insect chitin had characteristics similar to commercial chitin and are thus a suitable alternative in industrial application.