Characterization of Edible Insect, Cricket (Gryllus bimaculatus) Chitosan and its Application to Nanobeads

Abstract

Edible insects have been traditionally spent in many areas of the world and well known as the potential future resources. Among edible insects, the field cricket (Gryllus bimaculatus) is commonly consumed as a food around Asia and is of interest from an economic standpoint because this species have an energy content of approximately 120 kcal per 100 g of fresh weight of the whole insects. In previous studies, the chemical composition, nutritional quality of protein, fatty acids and chitin of field cricket species have been studied. This study was performed to assess characterization of cricket (Gryllus bimaculatus) chitosan and its application to nanobeads and its potential use in the food industry. The degree of deacetylation (DA), FTIR spectra analysis, X-ray diffraction (XRD), molecular weight (Mw), Scanning electron microscopy (SEM), color, zeta potential and pH value were measured. Finally, cricket chitosan nanoparticles (NPs) were prepared, and the optimal conditions (acetic acid concentration and addition of NaCl) were identified. All experiments were analyzed and compared with commercial chitosan. The results showed that the structural profiles derived from DA, FTIR, SEM and XRD analyses were similar to commercial chitosan. However, Mw of the cricket (Gryllus bimaculatus) chitosan was lower than that of commercial chitosan. In particular, much lighter color(off-white color or ivory) was observed in Cricket (Gryllus bimaculatus) chitosan than in commercial chitosan. Zeta potential and pH value were presented to 43.58 and 3.88, respectively, indicating the strong positive surface charges and acidic properties in cricket chitosan. As the results of the nanoparticles characterization, the particle size(208.27±3.47 nm), zeta potential(35.72±1.29 mV), polydispersity index (0.27±0.03) and mean count rate (255.92±3.23 kcps) were obtained. Increasing acetic acid and NaCl concentration reduced the nanoparticle size of cricket (Gryllus bimaculatus) chitosan. In conclusion, the field crickets could be a novel source of chitosan for the food, cosmetic and pharmaceutical industry.