Grilo preto (Gryllus assimilis) como candidato a material de referência certificado : um estudo de homogeneidade e massa mínima

Abstract

The analytical quality is a parameter of relevance in chemical analyses for guaranteeing the reliability and traceability of analytical results. Normally, it is achieved using Certified Reference Materials – CRM. However, not all matrices are available as CRMs in the market. As the edible insects are considered the future food in terms of meat substitution, the CRM production using this matrix type becomes fundamental. The present work has studied the utilization of black cricket insect (Gryllus assimilis) as a RM candidate by means of preparation, bottling and minimum mass determination and homogeneity assays, as well as the nutrient determination of this matrix. The sample preparation process consisted of milling, sieving and freeze-drying, followed by quartering and bottling of the material with posterior irradiation. The obtained batch was composed by 40 bottles containing 4 g of dried material and with maximum particle size of 80 μm. The residual humidity determination was carried out by the comparison of two drying methods (oven and freeze-dryer), while the mass minimum determination was performed by comparing the obtained values for analytical portions of 20 mg, 150 mg and 500 mg, applying the EDXRF (Cl, P and S) and FAAS (Cu, Fe, Mn and Zn) techniques. As the main property of the RM candidate, the homogeneity was assessed by the FAAS technique for evaluating the distribution of Cu, Fe, Mn and Zn in the material. The chemical characterization of the candidate was carried out through the EDXRF and ICP-OES techniques. The candidate showed residual water content of 7%, in which the best method for this determination was oven-drying. The results of minimum mass assay indicated that, among the analytical portions studied, 500 mg was the recommended minimum mass for the use of RM candidate, however, for some chemical elements, lower masses could be employed (between 150 e 500 mg). The preparation and bottling of the RM candidate was considered adequate since the homogeneity has been demonstrated for Cu, Fe, Mn and Zn at the 95% confidence level. With the chemical characterization, the material, besides of being protein source, had high concentrations of the Ca, Cl, K, Mg, Na, P and S nutrients, showing nutritional relevance.