Complex coacervation microcapsules by tannic acid crosslinking prolong the antifungal activity of cinnamaldehyde against Aspergillus brasiliensis

The antifungal activity and encapsulation properties of cinnamaldehyde-loaded microcapsules by tannic acid were investigated. The results showed that cinnamaldehyde exhibited a high in vitro antifungal effect against Aspergillus brasiliensis through altering the morphology of the hyphae, and its inhibition zone diameter (IZD) exceeded 15 mm with a minimum inhibitory concentration of 1.0 mg/mL. Cinnamaldehyde-loaded microcapsules crosslinked with tannic acid have a high encapsulation efficiency (92.53 ± 5.20%) and antifungal activity (37.82 ± 0.63 mm), and the retention rate was 2.5 times of that of unencapsulated cinnamaldehyde after 30-d storage at 37 °C. Furthermore, the antifungal stability was enhanced (IZD 25.37 mm) after 60-d storage at 37 °C as compared with that of cinnamaldehyde (IZD 22.07 mm). The results of cell membrane integrity and the extracellular protein content also indicated that the microencapsulation could effectively protect cinnamaldehyde, delay the decrease of antifungal effect and improve its long-term antifungal activity against A. brasiliensis by increasing the retention rate of cinnamaldehyde after storage.