Development and characterization of smart indicator composed of gelatin/carboxymethyl cellulose/morning glory anthocyanin for red meat freshness monitorin

Abstract

This study investigates the development and characterization of a new smart colorimetric indicator system based on anthocyanin-enhanced gelatin (Gel) and carboxymethyl cellulose (CMC) films for real-time monitoring of meat spoilage. This formulation combines natural anthocyanins with a Gel/CMC matrix, specifically designed to achieve broad pH responsiveness and clear visual discrimination of spoilage stages, addressing the need for effective natural indicators in intelligent food packaging. FTIR and SEM analyses confirm the successful integration of anthocyanin into the matrix, revealing minor spectral shifts and surface morphology changes that suggest enhanced intermolecular interactions. The indicator exhibits distinct pH-dependent color changes, transitioning from reddish at pH 3 to greenish-yellow at pH 12, as demonstrated by anthocyanin extract and film tests. In a practical application, smart indicator color packaged with meat shifts from red to yellow over 48 h, correlating with a pH increase from 5.8 to 8, indicating spoilage. Color parameter changes (L: 20.3 to 46.3, a: 21.3 to 10.6, b: 10 to 11.6) further support its sensitivity to freshness. These findings highlight the potential of this indicator as an effective natural tool for intelligent food packaging applications.