Amidated Pectin/Gelatin‐Based Films Containing Black Rice Anthocyanins and Their Coating Preservation Effect on Seriola aureovittata Fillets

Abstract

ABSTRACT This study developed a multifunctional intelligent film based on modified polysaccharides/gelatin (Ge) for freshness monitoring of Seriola aureovittata fillets. Structural characterization confirmed the successful synthesis of amidated pectin (AP) and oxidized carboxymethyl cellulose (OCMC). The black rice anthocyanin (BRA) pH indicator exhibited a distinct chromatic transition from light pink to dark purple across pH 3–11. Fourier transform infrared spectroscopy revealed that hydrogen bonding interactions between film components facilitated the formation of homogeneous matrices with a smooth surface morphology. Additionally, all film formulations exhibited strong oxidant activity against DPPH radical. Among all the fabricated Ge/AP/OCMC + BRA composites, the 5% BRA‐incorporated film (Ge/AP/DC‐5%) demonstrated optimal performance characteristics: enhanced mechanical strength (18.65 MPa tensile strength), superior hydrophobicity (127 ± 0.20° contact angle), improved barrier properties (3.51 × 10 −10 g/m·s·Pa water vapour permeability) and pronounced colorimetric responses to pH variations, ammonia and dimethylamine. Besides, Ge/AP/DC‐5% film could effectively monitor the freshness of S. aureovittata fillet during 4°C storage, with its colour turning from black (Day 0) to dark brown (Day 3) and light brown (Day 6) for freshness, moderate corruption and complete corruption, respectively. Meanwhile, all the other film formulations could also prevent the deterioration of S. aureovittata fillet in textural properties during 4°C storage for 6 days. These findings demonstrate the dual functionality of Ge/AP/DC‐5% as both active barrier and intelligent indicator in food packaging systems.