Preparation and Evaluation of Pullulan/Astragalus Extracts Bioactive Food Packaging Incorporated with β-Cyclodextrin and Its Anti-Browning in Apples

Polysaccharides-based bioactive films are regarded as a promising strategy to delay fruit spoilage. β-cyclodextrins (CD) was incorporated into pullulan/Astragalus extract (AE) bioactive films (CD-AE-P) to systematically investigate its effect on multi-scale structures features, physicochemical properties, migration behavior, anti-browning efficacy, and aroma substances in sliced apples. With increasing CD content, a slight blue shift was observed in O-H stretching vibration peak; CD-AE-P films retained an amorphous structure, as evidenced by the disappearance of scattering peak at 0.075 < q < 0.25 nm−1, and they exhibited smoother, continuous fractured surfaces with sparsely distributed protrusions. Meanwhile, CD incorporation contributed to the preservation of macromolecular thermal stability and induced an initial increase followed by a decrease in storage modulus (E′), with CD15-AE-P sample exhibiting the highest Tg value. Although the hydrophilicity increased marginally in the films upon adding CD, WVP decreased progressively, reaching a 23.3% reduction in CD25-AE-P relative to CD0-AE-P. Furthermore, total migration from the films was significantly suppressed by CD incorporation, and the anti-browning effect on sliced apples was extended; notably, treatment with CD25-AE-P effectively preserved the aroma substances of sliced apples during storage. These results demonstrate that CD serves as an effective functional carrier to modulate the effective release of bioactive compounds in active food packaging systems.