CHEMICAL AND NUTRITIONAL CHARACTERISTICS OF 

 FISH PROTEIN CONCENTRATE PROCESSED FROM 

 HEATED WHOLE RED HAKE, Urophycis chuss 



David L. Dubrow and Bruce R. Stillings' 



ABSTRACT 



This study was to determine whether cooking lean, whole fish before they are extracted by solvent af- 

 fects the chemical and nutritional characteristics of the resulting fish protein concentrate. When red 

 hake were heated at 100° and 109° C for as long as 80 min, the chemical and nutritional properties 

 of the fish protein concentrate were not adversely affected significantly. The nutritional quality was 

 slightly lower, however, in fish protein concentrate produced from red hake that were heated at 121° C 

 for 10 to 80 rain. 



Fish protein concentrate (FPC) contains pro- 

 tein tliat is high in quality. It tlierefore can be 

 used to supplement diets that contain inadequate 

 amounts of high-quality protein. 



Fish protein concentrate is prepared by re- 

 moving most of the lipids and water from whole 

 fish. Several methods for preparing FPC have 

 been investigated. They can be classified as 

 chemical, biological, and physical. Most inves- 

 tigators have used chemical methods in which 

 solvents extract the lipids and water from whole 

 fish. 



In the United States, two processes for making 

 FPC have been approved by the Food and Drug 

 Administration. Both of these are chemical 

 processes in which solvents are used. In the 

 overall program of the National Marine Fisher- 

 ies Service National Center for Fish Protein Con- 

 centrate, various approaches to processing are 

 being investigated. One such approach is cook- 

 ing and pressing fish prior to solvent extraction. 

 This procedure would tend to reduce the volume 

 of solvent required for extraction, inasmuch as 

 water and lipids would be expressed during the 

 pressing stage. 



Raw fish are diflicult to press because of their 

 physical consistency. The processor can over- 

 come this problem by cooking the fish before 



' National Marine Fisheries Service National Center 

 for Fish Protein Concentrate, College Park, Md. 20740. 



pressing them. If he subjects the fish to a high 

 temperature for a long time, however, undesir- 

 able chemical reactions may occur that decrease 

 the quality of the protein. 



The purpose of this study therefore was to 

 find whether or not the chemical composition 

 and nutritional quality of fish protein coilcen- 

 trate are altered when the FPC is produced by 

 solvent extraction of fish that have been cooked 

 at different temperatures for varying periods 

 of time. 



CHEMICAL COMPOSITION 



Reported here are both the proximate compo- 

 sition and amino acid composition of the FPC 

 produced from cooked fish. 



PROXIMATE COMPOSITION 



We used red hake, Urophycis chuss, which are 

 lean fish. They were caught off the coast of 

 New England in the area of Block Island, situ- 

 ated south southwest of Point Judith, R.I. The 

 hake were iced on board the vessel and were 

 then frozen in 25-lb. wax laminated cartons at 

 the dock. The hake were kept frozen while 

 being shipped to the National Marine Fisheries 

 Service National Center for Fish Protein Con- 

 centrate in College Park, Md. The shipment 

 contained about 96 cartons. From these 96 

 boxes, 15 cartons (375 lb.) were picked at 

 random for the investigation and were stored 



Manuscript received August 1970 



FISHERY BULLETIN: VOL. 69, NO. I, 1971. 



141 



