FISHERY BLXLETIN: VOL. 69, NO. I 



tein efficiency ratio than did the casein. Diets 

 containing FPC made from fish stored for 2, 6, 

 and 8 days in ice resulted in protein efficiency 

 ratios ranging between 3.59 and 3.65. The diet 

 containing FPC from the U-day-old fish yielded 

 a slightly lower gain in weight and a protein 

 efficiency ratio of 3.47. These results agree 

 with those obtained with the standard reference 

 samples made from the same fish. The nutritive 

 quality of the 1 1-day standard reference samples, 

 however, was poorer than that of the FPC 

 sample. This anomalous result suggests either an 

 improved utilization of protein as a result of ex- 

 traction with isopropyl alcohol or the removal 

 of some factor that may have depressed growth. 

 Freeze-dried fish produced from whole red 

 hake stored in ice 2 to 8 days did not differ in 

 protein quality. Freeze-dried fish produced 

 from whole red hake stored for 11 days, how- 

 ever, was lower in protein quality but still had 

 a protein efficiency ratio equal to that of casein. 

 FPC produced from whole fish stored for 2 to 

 11 days showed no diff'erences in protein quality. 

 All the FPC's had protein efficiency ratios high- 

 er than that of casein. 



SUMMARY AND CONCLUSIONS 



Whole red hake were stored, in ice for 2, 6, 8, 

 and 11 days. The fish were organoleptically 

 evaluated for freshness at each storage period 

 and were then processed by freeze-drying to 

 form a reference sample or by solvent extraction 

 with isopropyl alcohol to form a fish protein 

 concentrate. These products were then analyzed 

 for proximate composition and amino acid con- 

 centration and for protein quality. 



The results of the subjective evaluation for 

 freshness indicated that the fish stored up to 8 

 days were still acceptable for food but that those 

 stored for 11 days were not acceptable. 



The proximate composition and the amino 

 acid concentration of the freeze-dried whole 

 samples of fish showed very little change as a 

 result of the storage of the raw fish in ice. Rat- 

 feeding tests indicated a loss in protein quality 

 of the freeze-dried sample prepared from 11- 

 day-old raw fish. Protein efficiency ratio values 

 ranged from 3.35 to 3.49 for fish stored up to 8 



days, whereas the llth-day sample resulted in 

 a protein efficiency ratio of 3.18. All protein 

 efficiency ratio values, however, were equal to 

 the value for casein or were higher. 



The proximate composition of FPC's pro- 

 duced from fish stored up to 8 days in ice re- 

 mained relatively constant. The crude protein 

 in the concentrate produced from fish stored for 

 1 1 days decreased about 2.5 9f  The concentra- 

 tion of amino acids also followed this pattern 

 with a resultant lowering in the concentration 

 of lysine and a slight increase in that of proline 

 and glycine. The protein quality of the FPC 

 processed from the 11-day-old fish was also 

 slightly lower than that of FPC processed from 

 fresher fish. All FPC's, however, had protein 

 efficiency ratios higher than that of casein. 



We conclude that storage of whole hake in 

 ice up to 8 days is a satisfactory means of hold- 

 ing them prior to extracting the ground hake 

 with isopropyl alcohol to produce FPC. 



LITERATURE CITED 



Brown, Norman L., and Harry Miller, Jr. 



1969. Experimental production of fish protein con- 

 centrate (FPC) from Mediterranean sardines. 

 Commer. Fish. Rev. 31(10): 30-33. 

 Campbell, J. A. 



1960. Evaluation of protein in foods for regulatory 

 purposes. J. Agr. Food Chem. 8(4): 323-327. 

 Cohen, Edward H., and John A. Peters. 



1963. Effect of storage in refrigerated sea water 

 on amino acids and other components of whiting 

 (Merluccius bilinearis) . Fish. Ind. Res. 2(2): 

 5-11. 



DuBROw, David, and Olivia Hammerle. 



1969. Holding raw fish (red hake) in isopropyl 

 alcohol for FPC production. Food Technol. 23(2) : 

 254-256. 

 HoRWiTZ, William (chairman and editor). 



1965. Official methods of analysis of the Associa- 

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 Association of Official Agricultural Chemists, 

 Washington, D.C., xx + 957 pp. 

 Smith, Preston, Jr., Mary E. Ambrose, and George N. 

 Knobl, Jr. 



1964. Improved rapid method for determining total 

 lipids in fi.sh meal. Commer. Fish. Rev. 26(7) : 1-5. 



Spackman, Barrel H., William H. Stein, and 

 Stanford Moore. 



1958. Automatic recording apparatus for use in 

 the chromatography of amino acids. Anal. Chem. 

 30(7): 1190-1206. 



150 



