Black discoloration of spiny lobster of genus Panulirus white. IV. Influence of freezing, storing and thawing on melanin formation in lobster tails.

Abstract

There is little information as to the black discoloration related to frozen lobster, because of the negligible incidence of this phenomenon. However, when the refrigeration machine is out of order on board, it noted that large volume of lobster tails has been lost by melanosis here in Northeastern Brazil.It is very important to acquire a better knowledge on the relationship of technological facts between melanosis and freezing, storing and thawing.Live injured lobsters whose enzymatic reaction process could reach certain advanced stages under slow freezing rate were observed to have occurrence of darkening in spite of low storage temperature at -20°C. Melanosis was inevitable for lobsters once injured in the live state in the process of storing and thawing.However, quick freezing showed better effect of preventing discoloration in comparison with slow freezing owing to slower enzymatic oxidation, and thawing must be under relatively low temperature. While, lobsters died without anything injuries show nothing problem of darkening.