Effects of different packaging methods on the storage quality of mulberry–purple potato compound freeze-dried fruit blocks

During extended storage, dried foods experience color fading, nutrient degradation, and flavor loss. Appropriate packaging is essential to maintain food quality and economic value. To improve the storage quality of mulberry-purple potato compound freeze-dried fruit blocks (MPFBs), we evaluated 4 packaging methods: aluminum foil vacuum packaging, aluminum foil nitrogen-filled packaging (AN), nylon vacuum packaging, and nylon nitrogen-filled packaging. The changes in color, texture, active nutritional components, and volatile flavor compounds under different packaging conditions were systematically analyzed. The results revealed that the quality of MPFBs under all four packaging methods declined during storage. However, AN packaging demonstrated the best performance in terms of color stability, texture consistency, and retention rates of nutritional components (total phenols, anthocyanins, etc.). After 120 days of storage, the anthocyanin retention rate reached 79.59%, which was 23.8% and 18.17% higher than that of NV and NN packaging, respectively. Additionally, the phenolic compound retention rate reached 98.25%, significantly higher than other packaging methods ( P < 0.05). Electronic nose and -gas chromatography-mass spectrometry analysis identified esters, ketones, olefins, and aromatic hydrocarbons as characteristic flavor compounds in MPFBs. The flavor response value of AN packaging remained close to the initial state after 60 days of storage, with no significant deterioration in odor characteristics. This study systematically elucidated the impact of different packaging methods on the storage quality of MPFBs. Considering both nutritional components and flavor characteristics, AN seems to be the optimal packaging method for MPFBs. Our results provide a theoretical foundation for extending the shelf life of oxidation-prone lyophilized products.