Green Tea Extract: A Natural Alternative to Sodium Metabisulfite for Melanosis Inhibition in Black Tiger Shrimp

Aquaculture, with a history spanning thousands of years, has seen significant growth since the 1960s. India plays a substantial role in seafood exports, with shrimp being a significant contributor to its total seafood exports and holding a leading share in key international markets. Among the various shrimp species, Penaeus monodon is also known as giant tiger shrimp or black tiger shrimp. A common post-harvest challenge in shrimp is melanosis, or black spot, which affects the sensory qualities, reduces shelf life and diminishes commercial value. This melanosis is a metabolic reaction caused by polyphenol oxidase (PPO) enzymes, which produce dark pigments called melanin. While chemical substances like sodium metabisulfite (SMBS) is often used to inhibit PPO activity, concerns regarding their safety have led to a search for natural alternatives. Research suggests that natural plant extracts, such as green tea, can effectively prevent black spots in shrimp during storage. Green tea is known for its antioxidant, antimicrobial, and antimutagenic properties. The study evaluated the effectiveness of green tea extract in controlling black spot formation in freshly harvested black tiger shrimp. Green tea extract proved to be an effective inhibitor of melanosis in black tiger shrimp, presenting a viable natural alternative to sodium metabisulfite (SMBS). Also found that higher concentrations (3%) of both treatments were more effective in preventing black spot formation. Furthermore, cold storage (<4°C) notably enhanced the preservation effects across all treatments.