Fast production of highly sensitive nanotextured nonwovens for detection of volatile amines, bacterial growth, and pH monitoring: New tools for real-time food quality monitoring

Abstract

An efficient manufacturing of colorimetric nonwoven indicators represents a promising alternative to enable applications of such materials in food quality monitoring. The objective of this study is to use the solution blow spinning technique (SBS) to rapidly produce colorimetric nonwoven indicators based on polycaprolactone, incorporating natural or synthetic pH indicators to detect volatile amines, bacterial growth and monitor pH. Produced via the SBS method, these indicators were characterized aiming their physical, mechanical, thermal, and spectroscopic properties, evaluating their efficacy in detecting amines, monitoring bacterial growth, and pH, as well as assessing color stability during storage. The thermal stability and mechanical properties of the nonwovens practically always increased with the incorporation of natural and synthetic indicators. When exposed to volatile amines, the nonwoven indicators, particularly those embedded with bromophenol blue, displayed remarkable color change abilities in the presence of five volatile amines. These smart nonwovens in direct contact with E. coli K-12 or its volatiles in 24 h changed their color perceptible to the naked eye. The nanofiber nonwovens displayed visible color changes (ΔE ≥ 3) in response to buffer solutions (pH between 3 and 10). The smart nonwovens rapidly produced by the solution blow spinning method prove to be a promising tool for real-time monitoring of food freshness.