Development And Application Of Indication Label For Fish Freshness Detection Based On Tetraphenylethene Functionalized Polyaniline

Fish has high water content and delicate muscle tissue,but it is easy to to spoilage and deterioration under the combined action of microorganisms and enzymes,thus has an impact on food safety.Traditional methods have been successfully applied for evaluating freshness of prepared fish.However,they are expensive,sample-destructive and time-consuming.This is why the development of novel techniques to rapidly and non-destructively assess freshness of fresh food is much needed.Based on two new materials,tetraphenylethylene and polyaniline,this study developed a colorimetric and fluorescent dual sensing smart with aggregation induced emission and p H sensitivity label,through the color and fluorescence signal of the label to display the changes of the internal environment of the packaging to feed back the fish freshness level,combined with the intensity of the label signal to quantitatively determine the fish freshness.The main contents are as follows:Firstly,the grade of Sciaenops ocellatus freshness under room temperature and cold storage was divided by microorganism and physicochemical index,which provided research basis for the design of freshness index label.The level of freshness is divided into fresh,still fresh and splashed.Secondly,the performance and structure of polyaniline / tetraphenylethyene freshness indicator label were analyzed.The results show that polyaniline / tetraphenylethyene is successfully applied and covered on the surface of the blank polyamid films substrate and tetraphenylethyene is stably fixed in the pores of the polymer polyaniline;When the p H changes from 3 to 10,shows the color of polyaniline / tetraphenylethylene dispersion changes from green to blue,and the fluorescence intensity increases gradually.Through the analysis of the color rendering effect of the freshness indication label,it is shown that in the process of fish corruption,the indication label can not only show the change of color from turquoise to cyan to blue,but also show the change of fluorescence from black to dark blue to bright blue under ultraviolet light.This kind of color comparison and fluorescence double response indication Label improves the accuracy and sensitivity of fish freshness detection.According to the change of color and fluorescence intensity of freshness indication label,the ΔE value and TVB-N value showed good linear correlation in a certain range.The linear fitting equation of ΔE value and TVB-N value can be used as the basis for judging fish freshness grade and TVB-N content in fish meat.Finally,the intelligent label designed with polyaniline / tetraphenylethyene freshness indicator material is selected and applied in the actual samples.Taking Sciaenops ocellatus and turbot as examples,the color and fluorescence changes of the indicator area of the intelligent label are compared with the color comparison area.The results show that the intelligent label can judge the freshness level of Sciaenops ocellatus and turbot quickly and conveniently.Therefore,the smart tag can be used as an effective method of freshness nondestructive testing.