Melanosis is an enzymatic reaction harmless to consumers and not directly associated with spoilage of crabs, however it affects sensory properties thus reducing the shelf life and quality of the product. In this thesis, the effect of potassium metabisulfite, 4-hexylresorcinol and green tea extract, alone or in the form of a commercially available product (Neocel, Crustaxyl) on the sensory changes and development of melanosis in deep-water rose shrimp Parapenaeus longirostris (Lucas, 1846) was investigated. Additionally, treatments were compared over a period of 19 days in ice and slurry ice. Sensory properties of shrimps changed depending on the treatment applied. The results suggest that melanosis as a natural process cannot stop and can only be prevented for a particular time. The most effective treatment was Neocel in concentration of 1.5% used on shrimps stored in slurry ice. This treatment postponed melanosis during 19 days of storage. Good results were achieved by 3% Neocel stored in slurry ice which prevented the development of melanosis over 17 days. On day 13 of storage, shrimps treated with potassium metabisulfite (5%) achieved maximum quality index grades for colour in shrimps stored in both ice and slurry ice. All treatments showed better efficacy on shrimps stored in slurry ice. Beside treatment, the quality of the raw material was greatly depended on chilling and handling procedures as well as hygiene procedures.