A simple paper-based color change label using plant extracts for Ammonia gas detection

Paper and plant extracts are materials that are cheap and easy to find everywhere, have great potential to be used as a portable, low-cost and biodegradable label for the application of chemical compounds detection. In this paper, we have explored potential methods for the label to detect ammonia gas, an indicator of meat spoilage, with the colorimetric principle. By immersing paper with plant extracts that are sensitive to ammonia, in this case, is anthocyanin from Ruellia simplex flower extract, the detection of ammonia at various concentrations can be achieved. Ammonia concentration used is 0; 0.005%; 0.025%; 0.1%, 0.25% and 0.5%. Color change images on the label when detection is scanned by a flatbed scanner. ImageJ software is used to quantify the color changes. Ammonia detection at various concentrations results in a color change from red to yellow on the paper label. Paper-based labels with discoloration that can be captured visually by the consumer's eyes are considered as promising approaches to determine the freshness of meat.