The colorimetric sensor for volatile amines (VA) detection can realize non-destructive monitoring of shrimp quality. However, its sensing performance still needs to be improved. In this study, we proposed an aerogel-type colorimetric sensor to improve VA sensing performance and realize early detection of shrimp spoilage. The sensor was composed of konjac glucomannan-based aerogel prepared by sol-gel and freeze-drying, and pH-responsive dyes (neutral red) which were adsorbed on the aerogel surface. The sensor could show color change from pink to orange under the exposure of NH3, a marker of spoiled shrimp and the Euclidean Distance (ΔE) of the sensor was positively correlated with NH3 concentration. Due the three-dimensional network of the aerogel and its adsorption performance, the sensitivity of the aerogel-type sensor in NH3 detection was ∼6 times higher and the maximum ΔE was ∼1.5 times higher compared with the film-type sensor. It also showed stable sensing performance under various environment and was further successfully used in shrimp freshness monitoring. It was found that ΔE higher than 23.88 indicated the spoilage of shrimp. The above results provided a general approach for the designing of high-performance colorimetric sensor for real-time and non-destructive monitoring of shrimp freshness.
Keywords: Aerogel; Colorimetric sensor; Dye adsorption; Shrimp freshness; Volatile amines.
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