A 3D aerogel-like porous composite for colorimetric sensing with sumac anthocyanins and silica-stabilized LDH/nanofibers for rapid assessment of shrimp freshness

Freshness in seafood, especially in shrimp, is considered a significant matter in the food sector because of its high nutritional value as well as short shelf life. In this research, a new three-dimensional aerogel-like porous colorimetric sensor using sumac fruit ( Rhus coriaria ) anthocyanins, silica-stabilized magnesium-aluminum layered double hydroxide (LDH-Silica), and polyvinyl alcohol (PVA) nanofibers has been designed. This sensor can discriminate the volatile amines, which can provoke seafood spoilage, especially trimethylamine (TMA), showing a marked color change from pink hue to light green depending on TMA concentrations, which can visually estimate seafood freshness. The sensor has been synthesized through electrospinning/freeze-drying techniques, and its properties were examined through scanning electron microscopy, FT-IR, Thermogravimetric, and X-ray diffraction methods. The sensor's morphology is extremely porous and has a high thermal stability. There is a linear relation between ΔE values, which depend on color changes, and TMA concentrations in the 10-1000 ppb range (R² = 0.9961), detecting the minimum 11.56 ppb. In practical experiments carried out on real shrimp, its color change had an excellent correlation between total volatile basic nitrogen (TVB-N) content in line with Iranian National standards, ensuring high accuracy in shrimp freshness measurement. The sensor maintained stable performance for up to 120 days, after which a significant decrease in ΔE was observed