Anais do Simpósio Latino Americano de Ciências de Alimentos
Proceedings of 14 SLACA - Latin American Symposium on Food Science

The colorimetric indicators have the ability to indicate, in real time, the conservation status of food products and, therefore, present great potential for use as a tool to reduce food waste. Knowing that plasticizers may influence the chromic capacity of indicator substances added in polymeric bases, colorimetric indicators were produced by incorporating açaí anthocyanins extract (AE) in cellulose acetate (CA), added to different concentrations (1.8; 3.6; 5.4; 7.2 mols) of the plasticizers: glycerol (GLI) and triethyl citrate (TEC). The AE, adjusted at different pH values (2-12), was characterized by visible ultraviolet spectrometry. Plasticized colorimetric indicators were produced by the solvent evaporation method, on polymeric dispersion of CA in acetone at a ratio of 1:10 (w/v). The samples were analyzed by infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and by colorimetric and visual analysis under exposure to ammonia vapors, and to solutions at different pH's. In addition the sensors were analyzed for color change in real time on shrimp samples. The immobilization of plasticizers in the CA polymer matrix was confirmed by means of FT-IR spectra and SEM micrographs. The study of the chromatic behavior of the colorimetric indicators, produced with 7.2 mols of GLI and 1.8, 3.6 and 7.2 mols of TEC, under simulated condition, by exposure to ammonia vapors, exhibited more visually perceptible color changes. While the evaluation of the chromatic behavior on exposure to NaOH basic solution, showed that the indicators plasticized with GLI, exhibited better responses. With the results of the shrimp application analysis, it was found that colorimetric indicators incorporated with plasticizers can be used as a tool to effectively monitor shrimp freshness in real time. Furthermore, the color changes observed in the study were easily distinguished with the naked eye, suggesting their potential for use as smart packaging.