Armeniaca mume Sieb. blossom is among the traditional Chinese edible flowers, and it is widely used in the food and pharmaceutical industries. Flavonoids are among the most abundant bioactive compounds in A. mume Sieb. blossom. However, the research on the extraction of flavonoids from A. mume Sieb. blossom and their immunomodulating function is insufficient. In this study, we developed a microwave-assisted enzymatic extraction of flavonoids from A. mume Sieb. blossom (FAMB) and explored their immunomodulating effect on mice with dextran sulfate sodium salt-induced colitis. The results showed that the optimum parameters for microwave-assisted enzymatic extraction of FAMB were as follows: cellulase: 2.0%; microwave power: 200 W; microwave action time: 5 min; and enzymatic hydrolysis time: 50 min. FAMB significantly promoted the lymphocyte proliferation and natural killer (NK) cell killing activity in colitis mice, and increased the concentrations of TNF-α, IFN-γ, and IL-2 in serum. FAMB also significantly reduced the apoptosis of spleen lymphocytes in these mice. These results demonstrated that the microwave-assisted enzymatic method could significantly improve the yield and efficacy extraction of FAMB. FAMB showed a good immunomodulation effect on colitis mice.

Carboxymethyl chitosan (CMCS) is ideal for active packaging due to its non-toxicity and degradability, but its poor film-forming performance (strong hydrophilicity, weak mechanical properties, and low antibacterial activity) limits practical use. This study prepared a new edible antibacterial presFervation film (SDEWL-CMCS) by adding salted duck egg white lysozyme (SDEWL) to CMCS (as the film-forming substrate). It investigated how SDEWL concentration affects the composite film’s properties (thickness, water solubility, moisture/oil resistance, mechanical properties, and antibacterial activity) and tested the film’s preservation effect on small nectarines. The results showed the composite film had significantly improved packaging and antibacterial properties: compared to pure CMCS film, it had higher tensile strength, lower water solubility, better oil resistance and water vapor barrier performance, and stronger antibacterial activity against Escherichia coli and Staphylococcus aureus (larger inhibition zone diameters). The SDEWL-CMCS film effectively preserved small nectarines by inhibiting surface bacteria, regulating the preservation environment, and delaying fungal decay. This study confirms the film’s potential as a sustainable fruit packaging alternative, providing a theoretical basis for developing new fruit/vegetable preservation packaging and reducing the food industry’s reliance on non-degradable petroleum-based packaging.