Paper-Based Biopolymer Seafood Packaging with Integrated Colorimetric Ammonia Detection for Intelligent Barrier Technologies

There is a growing demand for bio-based intelligent packaging solutions to maintain and monitor food freshness. The bio-based material exhibits inadequate moisture resistance, making it unsuitable for its intended applications. In this work, coatings of shellac and a zeolitic imidazolate framework-67 (ZIF 67) of various proportions are developed. Some formulations show that there is a high barrier protection against water, moisture, and oil to enhance the shelf life of packed food. The presence of ZIF 67 within shellac on coated paper exhibits ammonia sensitivity to detect the freshness of shrimp. The ZIF 67 shellac composite-coated papers show improved barrier properties over uncoated paper. The improvement of water vapor transmission rate, water resistance, and grease resistance is 96.1% (<200 g·m^-2·day^-1), 82.2% (<2.3 g·m^-2), and 100%, respectively. Additionally, the coating enabled rapid ammonia sensing at -20 °C, the real-time storage temperature, with a detection limit as low as 5% (v/v) of ammonia with % color change (Δ<i>E</i>) of >57%. The experiments on storing shrimp food material with various materials indicated that the fabricated composite-coated paper showed a 40% improvement in storage time and a 12% reduction in drip loss compared to the uncoated paper. The coated paper gave a shelf life extension comparable to the polyethylene used as standard packaging material.