Enzymatic Time-Temperature Indicator Prototype Developed by Immobilizing Laccase on Electrospun Fibers to Predict Lactic Acid Bacterial Growth in Milk during Storage.

Ting-Yu Tsai,Li-Chen Chen,Hui-Huang Chen,Shih-Bin Lin,Shih-Hsin Chen,Shyi-Neng Lou,Yen-Hui Chen

doi:10.3390/nano11051160

Ting-Yu Tsai, Li-Chen Chen + Show 5 more

Open Access

https://doi.org/10.3390/nano11051160

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Abstract

Laccase was immobilized on a chitosan/polyvinyl alcohol/tetraethylorthosilicate electrospun film (ceCPTL) and colored with guaiacol to obtain a laccase time–temperature indicator (TTI) prototype. The activation energy (Ea) of coloration of the prototype was 50.89–33.62 kJ/mol when 8–25 μg/cm2 laccase was immobilized on ceCPTL, and that of lactic acid bacteria (LAB) growth in milk was 73.32 kJ/mol. The Ea of coloration of the TTI prototype onto which 8–10 μg/cm2 laccase was immobilized was in the required range for predicting LAB growth in milk. The coloration endpoint of the TTI prototype onto which 10 μg/cm2 (0.01 U) laccase was immobilized could respond to the LAB count reaching 106 colony-forming units (CFU)/mL in milk during a static temperature response test, and the prediction error was discovered to be low. In dynamic temperature response experiments with intermittent temperature changes between 4 and 25 °C, the coloration rate of the laccase TTI prototype was consistent with LAB growth. The results of this study indicate that the laccase TTI prototype can be applied as a visual monitoring indicator to assist in evaluating milk quality in cold chains.

Highlights

The function of packaging is to hold food
A polymer blend of polyvinyl alcohol (PVA) with CS was selected as the organic polymer and was cross-linked with TEOS through the coupling reaction [15], with the sol-gel method used to prepare hybrid fibers
The coloration rate increased with an increase in the amount of immobilized laccase; for the same amount of immobilized laccase, the coloration rate increased with an increase in the storage temperature (Figure 2). These results revealed that the coloration response duration of the laccase temperature indicator (TTI) prototype can be regulated through adjustment of the amount of immobilized laccase

Summary

Introduction

The function of packaging is to hold food. In recent years, package has expanded its function to protect food and improve storage quality (active packaging), to offer the quality information on the package (intelligent packaging), and to offer the communication function of the package to facilitate communication with consumers throughout the supply chain (smart packaging). An intelligent food package should serve the purposes of containment and protection and provide consumers with essential information regarding food quality to ensure food safety. As an intelligent food packaging technology, a time–temperature indicator (TTI). Enables monitoring food quality by its color changes based on the accumulation information of temperature and time, and it can be used to predict the condition of packaged food or its environment [2,3]. A TTI provides a continuous time–temperature history of foods, providing managers and consumers with reliable and accurate information related to food quality and safety. The TTI device is attached to the outer packaging of food and records and provides the time and temperature history of a food to observers [2]

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