Colorimetric indicators of açaí anthocyanin extract in the biodegradable polymer matrix to indicate fresh shrimp

Abstract

Colorimetric indicator or freshness indicators hold great potential to reduce food waste. Films off açaí anthocyanins extract (AE) with different concentrations molars of two plasticizers glycerol (GLY) or triethyl citrate (TEC), for application fresh shrimp, real time were evaluated. The AE undergoes a visible pink/violet to green/yellowish color change in response to different pH's, which is an indicator of microbial spoilage in shrimp. The CI were exposed to ammonia, and analyzed through infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), ultraviolet spectroscopy, and visual colorimetric. The immobilization of the plasticizers into the CA polymer matrices were confirmed through FT-IR spectra and SEM micrographs. In vitro chromatic transition of the indicators exposed to ammonia vapors, were visually more perceptible when they were produced with 7.2 mols of GLY or 1.8, 3.6, and 7.2 mols of TEC. For the real-time analysis of the application of colorimetric indicators in gray shrimp samples, the indicators that had plasticizers showed perfect color change at the exact time of food deterioration. The colorimetric indicators developed in this study using different molar concentrations of plasticizers are simple, effective and a great eco-friendly alternative to chemical sensors already developed so far.