Fiber-based materials are gaining attention as packaging materials for food and other products. Coatings are required for fiber-based materials to perform as needed. Replacing the petrochemical-based coatings used in fiber-based packaging materials with environmentally friendly alternatives to retain recyclability and biodegradability is desired. These alternatives should offer large-scale manufacturability, low cost, and barrier properties like petrochemical-based coatings for adoption. Shellac is a natural resin with good film-forming properties and hydrophobicity; still, very scarce information on shellac-coated fiber-based materials is available. It opens new possibilities for fiber-based packaging materials based on property improvement (e.g., enhanced barrier) and the capability to carry antimicrobial compounds. This study aims to develop, characterize, and validate multilayer shellac-coated bagasse paperboard with enhanced properties and the ability to release antimicrobial (ethanol). Part 1 of this thesis focuses on the properties improving properties of bagasse paperboard with the effects of shellac layering and concentration. Parts 2 and 3 focus on validating the developed shellac-coated paperboard as an ethanol emitter, its ethanol-releasing capacity, effectiveness against fungal growth (in-vitro studies), and a shelf-life study using packaged strawberries. Bagasse paperboard coated with 2 layers of 40% shellac showed 82% (water vapor permeability), 98.8% (oxygen permeability), and 97% water resistance improvement compared to uncoated paperboard. The bagasse paperboard coated with 40% shellac coating can withstand higher temperatures than cast film. Bagasse paperboard coated with 4 layers of 40% shellac released. 14,200 μL ethanol/L air (ppm) on day 1 and then showed a bi-phasic pattern (80% release within the first 10 days and the rest within 15 days). This ethanol-releasing paperboard reduced Penicillium spp. growth by 50% for 4 days and Botrytis cinerea growth by > 98% for 7 days in in-vitro studies at 23 °C. The developed shellac-coated bagasse paperboard when used as ethanol emitter inside packages with Botrytis cinerea-inoculated strawberries reduced mold growth by 30% and strawberry darkening while having no negative effect on fruit respiration, transpiration, and firmness at 23 °C. The developed multilayer shellac-coated paperboard has the potential to be used as a packaging material for food including more sustainable antimicrobial packaging by replacing plastic-based ethanol emitter.
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