Preparation, characterization of algae polyphenol-polysaccharide composite films and application in chilled porcine longissimus lumborum packaging

The objective of this study was to assess the efficacy of pullulan (PUL) based films incorporated with algae polyphenol extracts (APE) in preserving the freshness of porcine longissimus lumborum (PLL) during refrigerated storage at 4 °C for 7 d. Among 3 types of polysaccharides (tested konjac gum, soluble soybean polysaccharide, and PUL), the PUL-APE composite film demonstrated superior film performance. The effects of APE concentrations at 1, 2, 3, 4, and 5 % (w/v) on the barrier, mechanical, physical, and optical properties of the developed films were evaluated while exploring intermolecular interactions between APE and polysaccharides. Results revealed that increasing APE concentration significantly enhanced the thickness, moisture content, and water solubility of PUL-APE composite films while decreasing brightness and opacity rate (P < 0.05). Compared to other groups, the composite film containing 3 % APE exhibited superior barrier and mechanical properties with a minimum water vapor permeability value of 2.35 ± 0.05 g/m² and maximum tensile strength value of 55.82 ± 0.42 MPa. Additionally, the packaging effect of PUL-APE composite film on chilled PLL samples was investigated. The film effectively delayed microbial growth and minimized oxidative rancidity, texture changes, and cooking loss during refrigerated storage of PLL samples. Therefore, these PUL-APE composite films hold great potential as edible materials for meat packaging applications.