Shrimp shell waste contains chitin compounds which are useful in the food sector. The synthesis of chitin into chitosan can be useful as an edible coating on tomatoes. The research was conducted in three stages: the chitosan manufacturing process, the antibacterial test of chitosan, and the application of chitosan as an edible coating on tomatoes. The manufacture of chitosan consisted of the isolation of chitosan (deproteination, demineralization, depigmentation, and deacetylation) and characterization of chitosan (moisture content, ash content, solubility, and spectrum test using FTIR). The yields obtained from the manufacture of chitosan were deproteination (66.66%), demineralization (57.5%), depigmentation (58.79%), and deacetylation (59.65%). Chitosan characterization includes water content of 3.2% and ash content of 0.41%. FTIR spectra test on isolated chitosan resulted in %DD which was 87.2%. Antibacterial activity of chitosan with four variations of chitosan (0.25%; 0.5%; 0.75% and 1%) produced chitosan with the best inhibitory power at a concentration of 1%. At the chitosan application stage, the average data for each test was obtained, namely the weight loss test of 1.60%; the organoleptic test showed a slower colour change of tomatoes than the control; the test for reducing sugar content of 12.46%; vitamin C test of 36.31 mg/100g; total acid test of 7.79%; so that the use of chitosan as an edible coating has a significant effect on the shelf life of tomatoes.
