Bio-based Sensing: Role of Natural Dyes in Food Freshness Indicators

Abstract

Food dyes are substances or mixtures of compounds added to food and beverages, to confer or enhance the color of the product itself. Artificial dyes are easy to obtain and have a production process with lower costs when compared to natural dyes. However, consumers are increasingly concerned about their health and are looking for products that contain fewer artificial products and more natural compounds. The most commonly used natural dyes are carotenoids, betalains, chlorophylls, anthocyanins, curcumins and phycocyanins, which are present in various types of products, such as fruits and vegetables, algae, roots, leaves, among others, making them easily obtainable. These dyes can be used without any health risk in various types of food products as indicators of intelligent packaging. Sensors/indicators for intelligent packaging need to change color to inform the consumer that the product stored is undergoing changes and may no longer be viable for consumption. Natural dyes react to changes in pH, gases, time and temperature, microorganisms, oxidizing agents, and change color according to specific chemical reactions that occur depending on the environment they are in, being excellent quality indicators of food products. This chapter shows the various types of natural dyes that can be used in sensors/indicators for intelligent packaging, their color variations in different media, potential applications and the current research being carried out in this field of food packaging.