Exploring the effect of inhibitors, cooking and freezing on melanosis in snow crab (Chionoecetes opilio) clusters

Snow crab (Chionoecetes opilio) is a valuable crustacean either sold live or processed into two sections (i.e., clusters) and commercialized in a freshly-cooked or cooked-frozen form. The market value of snow crab clusters may be impaired by the development of melanosis, a blue-hued discoloration of enzymatic origin. This study explored the effectiveness of anti-melanosis treatments in solutions with commercially available melanosis inhibitors in conjunction with cooking and freezing. Digital image analysis, correlated to the response of a sensory panel, was used to determine melanosis progression during chilled storage. 4-Hexylresorcinol was the most effective melanosis inhibitor (p < 0.001). Phosphoric acid also showed a marginal, yet significant (p < 0.05), inhibitory effect. Ascorbic acid as well as cooking to a leg core temperature of 87 °C (±0.5) showed no effect on melanosis rate, which was instead accelerated by freezing or treatment with a mixture of acetic, ascorbic, citric and ethylenediaminetetraacetic acid. Overall, 4-hexylresorcinol has the potential to lower melanosis, which may otherwise occur very rapidly and markedly during chilled storage, especially in previously frozen clusters. Melanosis should be considered as a critical quality decay indicator in the shelf-life assessment of snow crab clusters.