Physicochemical Properties of Chitosan from Two Commonly Reared Edible Cricket Species, and Its Application as a Hypolipidemic and Antimicrobial Agent

Abstract

Insect-derived chitin and chitosan have gained interest as alternative sources to that derived from crustaceans; however, little information is available on chitin from the house cricket (Acheta domesticus) and tropical banded cricket (Gryllodes sigillatus), two cricket species commonly reared in the United States for human consumption. In this study, chitin was successfully isolated and purified from these two cricket species; using FTIR, chitins were found to be in alpha-crystalline form. Cricket chitosan was produced from both species with varying degrees of deacetylation (DDA) by varying alkaline conversion duration. G. sigillatus chitosan was larger (524 kDa) than A. domesticus chitosan (344 kDa). Both cricket chitosans showed similar (p > 0.05) lipid-binding capacity to that of shrimp chitosan. Both chitosans were as effective at inhibiting microbial growth of surrogate foodborne pathogens as the commercial shrimp chitosan. At a concentration of 0.50 mg/mL cricket chitosan, approximately 100% of Listeria innocua growth was inhibited, due to a contribution of both chitosan and the solvent-acetic acid. At the same concentration, growth of Escherichia coli was inhibited 90% by both cricket chitosan samples with ~80% DDA, where a decrease in the DDA led to decreased antimicrobial activity. However, varying the DDA had no effect on chitosan’s lipid-binding capacity. As more edible insects become a normalized protein source in our diet, the use of by-products, such as chitin and chitosan, derived from insect protein processing, show promising applications for the pharmaceutical and food industries.

Development of Chitosan Films from Edible Crickets and Their Performance as a Bio-Based Food Packaging Material

“…Molecular characterization of CCF (Figure 1) aligned well with spectra reported in previous chitosan-glycerol plasticized films characterized by FT-IR [18,24,25]. Additionally, CCF were not structurally different that SCF, as shown by the absence of spectral differences between all spectra.…”

“…Cricket chitin was extracted from a chitin-rich by-product produced during the enzymatic proteolysis of cricket proteins for food formulation [16,17]. In our previous study, cricket chitin from each species was effectively demineralized and deproteinized with acidic and alkali treatments [18]. Furthermore, cricket chitosan was deacetylated with concentrated and hot alkali treatment for varying durations.…”

“…Furthermore, cricket chitosan was deacetylated with concentrated and hot alkali treatment for varying durations. As previously optimized, cricket chitosans were produced with various DDA values as determined by FTIR, and within each cricket species the DDAs produced were found to be significantly different [18]. Deacetylation parameters for each cricket species were then chosen to produce a similar range of DDA values: 72, 76, and 80%.…”

“…Deacetylation parameters for each cricket species were then chosen to produce a similar range of DDA values: 72, 76, and 80%. For more specific details on the extraction, deacetylation, optimization process, and molecular weight determination of these samples, the reader is referred to Malm and Liceaga [18].…”

“…The molecular characterization of all chitosan films was analyzed as previously described [18] using Fourier Transform Infrared spectroscopy (FT-IR) (Thermo Scientific, Waltham, MA, USA) from 3500 to 800 cm −1 with a resolution of 8 cm −1 (n = 4). Spectra were obtained via film transmission using ATR with a diamond prism, and automatically baselined and averaged using OMNIC software (ThermoFisher, Waltham, MA, USA).…”