Studies on the Residue of Sulfur Dioxide and the Production of Formaldehyde in the Prawn Treated with Sodium Bisulfite

Abstract

The level of sulfur dioxide in the muscle portion of imported frozen prawn treated with sodium bisulfite ranged from 10 to 30 ppm, which was below the permissible residual amount (100 ppm) designated in the food additives standard under the Japanese Food Sanitation Law. However, at the same time, 4 to 6 ppm of formaldehyde was detected in the muscle. When the Japanese prawn (Penaeus japonicus Bate) Was dipped in 0.5 % solution of sodium bisulfite, 40 ppm of sulfur dioxide was recovered in the muscle immediately after the treatment, and 0.6 ppm and 1.5 ppm of formaldehyde were produced after 2 days of cold storage at 3°C and after 2 months of frozen storage at -20°C respectively, while no formaldehyde was detected in the muscle of the untreated prawn. It may be presumed that formaldehyde was generated from trimethylamine oxide in the muscle of prawn by a non-enzymatic reaction as a result of the treatment with sodium bisulfite. Sulfur dioxide in the muscle and shell of prawn decreased considerably during frozen as well as cold storage. © 1977, The Japanese Society of Fisheries Science. All rights reserved.