Inhibition of Flesh Browning and Skin Color Fading 

 in Frozen Fillets of Yelloweye Snapper (Luijanus vivanus) 



By 



HAROLD C. THOMPSON, JR. and MARY H. THOMPSON 1 



National Marine Fisheries Service 



Fishery Products Technology Laboratory 



Pascagoula, Mississippi 39567 



ABSTRACT 



Fresh yelloweye snapper (Lutjanus vivanus) which had been scaled and evis- 

 cerated were treated with the chemicals 3,3'-thiodipropionic acid, glutathione, di- 

 sodium ethylenediaminetetraacetate dihydrate in combination with propyl gallate, 

 and monotertiary butylhydroquinone. The inhibitory effects that these chemicals 

 had on flesh browning (Maillard reaction) were studied over a 12-month frozen 

 storage period. Also, the effects of vacuum packaging on snapper skin discolor- 

 ation were studied. 



INTRODUCTION 



The Gulf of Mexico red snapper fishery ori- 

 ginated off the northwest Florida coast 15 to 

 20 years prior to the Civil War (Carpenter, 

 19(55). Catches at that time were made with 

 the use of handlines from sailing vessels con- 

 taining live wells. At that time, ice for use 

 on commercial vessels was too expensive owing 

 to cost of shipping from the point of manu- 

 facture. 



The snapper fishery did not start on a large 

 scale until after the end of the Civil War ( War- 

 z - en, 1898). The fishery really began to bloom 

 when ice manufacturing plants began produc- 

 ing ice at a reasonable cost. With ice to cool 

 their catches, the crews of the snapper vessels 

 were able to go out farther and stay longer. 



1 Authors: Harold C. Thompson, Jr., Chemist, and 

 Mary H. Thompson, Research Chemist, National Ma- 

 rine Fisheries Service, formerly Fishery Products 

 Technology Laboratory, Pascagoula, Miss. 39567, pre- 

 sently Southeast Fisheries Center, Miami Laboratory, 

 Miami, Fla. 33149. 



Another boost was given to the fishery around 

 1920 when sail-rigged vessels became diesel 

 powered. The majority of the snapper fleet still 

 ices the fish in the hold; however, a few new 

 freezer vessels have entered the fleet. 



The total landings of snapper in the United 

 States for 1968 were 11,500,000 lb. valued at 

 $3,700,000 while the totals for 1969 were 

 9,500,000 lb. valued at $4,000,000 (Riley, 1970) . 



The present methods used in commercial pro- 

 cessing of snapper are limited to (1) eviscer- 

 ation and freezing the whole fish and (2) fil- 

 leting or steaking the fish and then freezing 

 them. The majority of the snapper are either 

 sold in a fresh iced condition or as eviscerated 

 frozen fish. The flesh of the fillets and steaks 

 turns from white to brown in color during ex- 

 tended periods of frozen storage, thus limiting 

 the market owing to lack of consumer eye 

 appeal. The red skin on the fillets and steaks, 

 one of the snapper's main selling points, also 

 fades in color to a beige or bronze during frozen 

 storage. Skin coloration is used by most large 

 firms as a quality indicator. 



