Abstract: Betalains, a group of naturally occurring compounds that grant coloration to some plants and fruits, are water-soluble nitrogen containing pigments. Categorized into betacyanins(violet) and betaxanthins(yellow), these compounds are best known for their many favourable characteristics including their stability, antioxidancy, environmentally friendliness, and cost-efficacy. Consumers are gradually becoming more cognisant with the physical appearance, nutrition value, and freshness of their food products. This research aims to highlight the potential application of betalains into food products as colorimetric indicators. Betanin, the compound commonly known for giving its color to beetroot, is used as a dye. Betanin is carefully integrated, formulated into an ink, and printed via piezoelectric ink-jet printing. Piezoelectric ink-jet printing is a novel technique that allows for the complete control of our manufactured sensor. Using the CYMK color codes on the printer, this application gives us the freedom to control exact amounts of deposition. Given this advantage, another cartridge is filled with a colourless acidic ink, which will allow us to print in combination with the betanin ink and control the starting pH of our halochromic sensor. The indicator is shown to react with the main volatiles released during fish spoilage: trimethylamine (TMA), triethylamine (TEA), and ammonia.
