Novel cost-effective Hibiscus flower based colorimetric paper sensor containing anthocyanins to monitoring the quality and freshness of raw fish

This article described the low-cost hibiscus flower based colorimetric paper sensor to monitor the quality and freshness of raw fish. The extract of hibiscus flower was used to develop pH sensing paper strips for qualitative analysis. The sensitivity of paper sensor was checked by colorimetric detection of ammonia gas and then it was implemented to monitor the freshness of fish visually. The extract of hibiscus flower containing anthocyanin molecules are the key molecule for visual detection of spoiled food. The above molecule was spectroscopically analyzed with change in pH of the solution before and after the interaction of food products. We also studied the variation of both color and shade of paper sensor with change in pH at natural and artificial light conditions. The color information extracted from images and their relationship with pH was explored in red, green, blue (RGB) and hue, saturation, and value (HSV) color spaces by the image-J software for qualitative monitoring of food. Anthocyanin based paper sensor is used as a convenient and real time smart food sensor in packaging application.