Super Hydrophobic Pectin-Anthocyanin Colorimetric Sensor to Indicate Freshness in Bovine Meat

In this work, an innovative three-layer sensor was developed in a fully sustainable design. For that purpose, pectin and anthocyanins from Morus nigra and Prosopis alba were used. Furthermore, mixtures of beeswax and colophony as hydrophobic layers were used to prevent the moisture from affecting the sensor work. The ratio of beeswax/colophony (B/C) was studied to optimize the moisture barrier. The response of colorimetric sensors pectin-Morus nigra (PMN) and pectin-Prosopis alba (PPA) in vapors of simulant solutions was recorded. Furthermore, physicochemical and microbiological tests on fresh bovine meat were carried out, and volatile compound content (VC) was correlated with color changes in PMN and PPA sensors. The results depicted that the optimal ratio in the waterproof layer was B/C: 70/30 (BC3) showing the highest water contact angle of 112° and minimal water vapor absorption value of 2.4%. In addition, the light transmittance of the BC3 layer allows to perceive the color of the sensor without alteration. The outcomes of the simulation test showed differences in color values of 26 and 31 to PMN and PPA, respectively, highlighting the ability of both sensors to allow the detection of quality changes in packaged bovine meat. This research paves the way for the development of sustainable and environmentally friendly colorimetric sensors with diverse applications.