Encapsulation of lemongrass essential oil into cassava starch fibers for application as antifungal agents in bread

This study aimed to inhibit fungal spoilage in bread by applying cassava starch fibers loaded with lemongrass essential oil (LEO). Cassava starch was extracted and measured for amylose content, and the LEO was extracted and characterized for chemical composition. The starch-LEO polymeric solution was prepared at various LEO concentrations (0, 20, 30, and 40%, v/w) and evaluated for rheological parameters. The fibers were produced by electrospinning and evaluated for morphology, size distribution, FTIR spectra, thermogravimetric properties, contact angle with water, mechanical properties, antioxidant activity against DPPH, OH, and NO radicals, and in vitro and in situ antifungal activities in bread against Penicillium crustosum and Aspergillus flavus. The amylose content of cassava starch was 27.3%, and LEO showed citral as the major compound (β-citral and α-citral). Incorporating LEO into the polymeric solutions did not affect the viscosity, and the fibers displayed homogeneous and continuous morphologies with mean diameters ranging from 460 to 577 nm. The FTIR spectra of the fibers showed characteristic bands of their constituents (starch and LEO). The fibers presented high thermal stability and antioxidant activity, and low contact angle with water and tensile strength. The in vitro assays revealed that LEO had inhibitory and fungicidal effects, and starch-LEO fibers only had an inhibitory effect. For the in situ assays, the treatments were applied as two systems directly in the bread dough and as membranes in active bread packages. The fibers with 40% LEO showed great antifungal activity (for both systems), reducing the fungi count compared to the other treatments (control, free LEO, and 0% LEO fibers) applied over the storage period analyzed (0, 5, and 10 days). Therefore, the cassava starch-LEO fibers are a promising antifungal agent to replace synthetic additives applied to the food matrix and as active packaging for bread.