Desenvolvimento e avaliação de método rápido de análise semiquantitativa de cianeto total em derivados de mandioca

Abstract

Because cassava is a raw material rich in cyanogenic compounds, and of safety issues, it is necessary to know the cyanide residues in the final products of flour, tucupi and maniva, since when ingested it can cause intoxication and development of chronic diseases. This work aimed to study a rapid and semi-quantitative method of analysis of total cyanide (kit) in cassava derivatives. Total cyanide determinations were carry out on roots and leaves of cassava, and their derived products (dry flour, tucupi and maniva) to evaluate the range of work to be proposed for the kit. The components of the kit were developed based on spectrophotometric methodology widely used in cassava research. It was established the storage time of the components of the developed kit and its validity from the figures of merit linearity, repeatability, working range and limit of detection. The total cyanide concentration in the cassava derivatives showed a distinct behavior among the samples, indicating a predominance of non - glycosidic cyanogenic compounds and linamarin residues. A suitable form of dehydrated and partially purified enzyme was developed from the precipitation of cassava weevil extract with ethanol solvent. The kit contains dropper bottles with buffer and alkaline solutions, color reagent, and enzyme on filter paper, stored in multilayer laminated packaging, which also sets up as the reaction vessel. This format was able to present visually differentiated color responses for the total cyanide concentration ranges in tucupi, flour and maniva samples. The stability study indicated that the kit should be stored under refrigeration and used in the maximum period of 30 days, for tucupi analysis, but with adjustments for the analysis of flour and maniva. The kit showed linearity between 1.03 and 3.97 μg of HCN per reaction package with correlation coefficient of 0.9898; working range between 5 and 100 ppm; relative standard deviation less than 3%; limit of detection of 5 ppm and recovery index between 88 and 94%.