Melanosis or Black-spot

Melanosis, also known as black-spot, is the development of black pigments on the exoskeletons of crustacean's postmortem (Montero et al. 2004). Black-spot is caused by a system of enzymes that are naturally present in the shrimp. These enzymes, in the presence of air, can chemically transform colourless compounds in the shrimp into complex brown pigments near the shrimp surfaces and shell.

Black-spots occur mostly due to discolouration, which is a defect caused by the activity of Tyrosinase during storage (Mu et al. 2012; Tsironi et al. 2009). Tyrosinase is a copper-containing enzyme present in plant and animal tissues that catalyses the production of melanin and other pigments from tyrosine by oxidation. It is found inside melanosomes which are synthesized in the skin melanocytes.

On shrimp, black-spots typically begin on the cephalothorax and caudal tip of the tail, before spreading to the rest of the shell. Melanosis is a major issue in the marketability of the product with the consumer.

A major challenge in aquaculture and wild-caught sectors is ensuring that freshly caught Shrimp, Prawn and other Crustaceans should retain their full market value.

Shrimp and Prawn are important aquatic species for use in aquaculture and for their catches worldwide for human consumption. The quality and shelf life of shrimp/prawn freshly harvested from different ponds/farms or catches from seas/rivers are usually stored on ice and then freezes. To quantify the quality and shelf life is difficult to assess the untreated shrimp.

NatuFresh is a Food Grade formulation with 1,3-Dihydroxy-4-Hexylbenzene which effectively avoids the development of melanosis/black-spot and helps to retain the original colour and texture of the catch for extended periods.