This study optimized the extraction process, achieving a yield of 83% cellulose and 76% nanocellulose using 8% sodium hydroxide (NaOH) solution and 90% ascorbic acid. The methodology began with grinding 200–250 g of rice husk into a fine powder and adjusting its moisture content to 35% for efficient processing. The moistened sample is soaked and passed through a food extruder to break down its structure further. Alkali treatment with 8% NaOH at 50°C for 2.5 hours removes lignin and hemicellulose. The material is then washed with distilled water until neutral pH is achieved. Bananas, one of the most widely consumed fruits worldwide, are highly perishable, with a rapid ripening process that leads to significant postharvest losses. Enhancing their shelf life is crucial to reducing food waste, improving marketability, and meeting consumer demands for fresh produce. This study investigates the development of cellulose- and nanocellulose-based edible coatings, incorporating glycerol, Tween 80, katira gum, and distilled water in varying proportions, to evaluate their effectiveness in preserving banana quality during storage. The most effective composition contained 8% nanocellulose, 0.5% katira gum, 5% glycerol, 1% Tween 80, and distilled water. This formulation significantly delayed ripening, maintained firmness, reduced weight loss, and preserved overall quality by forming a uniform, thin layer that minimized moisture loss and reduced respiration rates.