Applications of enzymatic time–temperature indicator (TTI) devices in quality monitoring and shelf-life estimation of food products during storage

Abstract

The temperature abuse encountered by food products during storage due to deviations from the recommended storage conditions often leads to a considerable loss, especially for frozen and refrigerated foods. From a consumer perspective, the real history of time–temperature data is of interest so that the customer can get an idea about the remaining shelf-life. The time–temperature indicator or integrator (TTI), a small and inexpensive device, is attached to the packaging material and provides the time–temperature history of a food product during storage, thus estimating remaining shelf-life in a non-destructive manner. The enzymatic TTI is based on a thermo-sensitive reaction between enzyme and substrate. A suitable dye is mixed into this medium as an indicator, which changes its color depending on the variation in the pH of the reaction medium. In the recent past, several TTIs have been developed based on different enzymes, including lipase, amylase, phospholipase, urease, laccase, and others. The corresponding applied food matrices were fruits, vegetables, milk products, seafood, poultry, and meat products. Developing a new enzymatic TTI requires a systematic approach to correlate the response-TTI dependency. Such development needs a thorough understanding of the kinetics of food quality attributes and the activation energy. This review provides an overview of enzymatic TTI, theoretical considerations, and the systematic approach required to develop any enzymatic TTI. The integration of such information will simplify the design of novel enzymatic TTIs for a wide array of food products during frozen storage.