Freshness/spoilage monitoring of protein-rich foods by betacyanin-loaded gelatin/carboxymethyl cellulose halochromic labels
Reza Abedi‐Firoozjah, Shamimeh Azimi-Salim, Arvin Afrah, Reza Atef Yekta, Elham Assadpour, Maryam Azizi‐Lalabadi, Seid Mahdi Jafari
Abstract
In the present investigation, easy-to-use colorimetric on-package labels were developed based on gelatin/carboxymethyl cellulose films loaded with betacyanin-rich Mirabilis jalapa extract (MJE) for freshness tracking of shrimp and minced meat . The effect of MJE addition (2 %, 4 %, and 6 % (w/v)) on the morphology, micro-structural, optical, and functional characteristics of the labels was assessed. The addition of MJE indicated dose-dependent improvement of antioxidant potential and light barrier capability of the labels but the reduction of their mechanical strength and water barrier properties. The labels underwent color changes (pinkish-red to yellow) after being exposed to different pHs (2–13), which was similar to the MJE solutions when immersed in buffer solutions. The halochromic label loaded with 6 % (w/v) MJE exhibited the highest sensitivity to ammonia. This label was also capable of detecting ammonia concentrations ranging from 0.01 to 0.1 mg/mL, with a visible color shift from red to pale yellow. When utilized for freshness monitoring of shrimp and minced meat , this label displayed noticeable color changes resulting from the accumulation of volatile ammonia and changes in pH during the spoilage of these samples. The labels were also biodegradable, disintegrating within ∼21 days to a great extent. As a result, we found that a label containing 6 % (w/v) MJE can be used as a biodegradable halochromic indicator in the food packaging industry for visual quality monitoring of seafood and meat products.