Studies on phenoloxidase activity and its sensitivity to metabisulphite in frozen metapenaeus monoceros

Abstract

The incidence of black spot in frozen prawns was observed in many cases during thawing at tropical ambient temperatures. A dip in 0.5% (100% purity basis) sodium metabisulphite solution for 30 seconds controlled black spot in frozen Metapenaeus monoceros upto 10 months. Phenoloxidase activity in the shell extract of prawn showed a decreasing trend during frozen storage (-180C). The activity was lower in the sulphite treated sample when compared with the untreated sample. Residual sulphur dioxide in thawed meat was within permitted limits.