Development of chitosan-based films and microspheres impregnated with plant extracts with antimicrobial properties: application in the industry and agriculture

Abstract

Antimicrobial compounds extracted from natural sources have great potential in the control of bacterial and fungal contamination in the food industry. They are found in herbs, spices, fruits, seeds, leaves and animal shells, constituting a new, safe and environmentally recommended option, since that wastes can be utilized as antimicrobial sources. In the alcoholic fermentation for fuel ethanol production, the conventional strategies for the control of bacterial growth involve the utilization of antibiotics and cell treatment with sulfuric acid. Problems regarding to the increase in antibiotic resistance found in bacteria isolated close to distilleries and even the high cost of its application, besides the dangerousness of the handling of sulfuric acid in the cell treatment between the fermentative cycles, have stimulated the search for nonconventional strategies to combat the contamination. The objective of this project is the utilization of shrimp wastes to obtain chitosan by bacterial fermentation (Lactobacillus plantarum), following by chemical deacetylation of chitin to obtain chitosan, and then preparing films and microspheres of chitosan impregnated with extracts of fruit seeds and peels. The films and microspheres will be characterized and tested against contaminant micro-organisms of the ethanolic fermentation and against phytopathogenic fungi in vitro. Further, the microspheres will be tested during the ethanolic fermentation in two steps of the process: during the acid treatment of the cells that occurs between the fermentative cycles; and during the fermentation itself. Regarding the films, a test with tomato will be carried out to verify the utilization of the film in the control of the growth of fungi causing postharvest rot. The idea here is to expand the possibility of using the set chitosan + plant extracts to another sphere of application, in the agriculture. (AU)