FISHERY BULLETIN: VOL. 69. NO. 1 



ed by the observed decrease in yield after pro- 

 cessing — namely, 12.0 percent of 2-day-old fish 

 to 10.0 percent of 8-day-old fish. 



Storage of whole red hake in ice up to 11 days 

 did not influence the extractability of the lipids. 

 A slight loss of nitrogen occurred, however, dur- 

 ing the processing of whole fish stored for 11 

 days as compared with fish stored for shorter 

 periods. 



AMINO ACID COMPOSITION 

 Standard Reference Sample 



Amino acids were determined by the method 

 of Spackman, Stein, and Moore (1958). 



Table 4 shows that the recovery of amino 

 acids was relatively constant at about 92'^^'c of 

 the protein. The essential amino acids for 

 which analyses were made ranged between 45.5 

 and 46.3 "^r of the total. No major change in 

 the pattern of any one particular amino acid 

 resulted from storage. 



In general, this finding agrees with those by 

 Cohen and Peters (1963) on whiting, Mer/«cc»« 

 bilinearis, that were stored in ice. These auth- 

 ors reported, however, that methionine de- 

 creased after the 13th day with a subsequent 



Table 4. — Amino acid composition of raw freeze-dried 

 whole ground fish. The samples were prepared after fish 

 were held in ice for periods up to 11 days. 



increase in methionine sulfoxide. We do not 

 know whether this compound was present in the 

 hake that we studied. 



Fish Protein Concentrate 



The same methods were used as with the 

 standard reference sample. That is, the amino 

 acids were determined by the method of Spack- 

 man, Stein, and Moore (1958). 



Table 5 shows the concentration of amino 

 acids in the FPC's processed from the fish held 

 in ice. The data indicate that about 1009c of 

 the amino acids were recovered. 



The essential amino acids constituted 47% 

 of the total amino acids in the FPC made from 

 fish stored 2 days, but the concentration of these 

 amino acids dropped to 43 Sr after the fish had 

 been stored 11 days. Individual amino acids 

 decreased in concentration. Of these amino 

 acids, leucine and isoleucine decreased slightly, 

 whereas lysine and histidine decreased markedly 

 after the 8th day of storage. The total concen- 

 tration of lysine was about 11 '^r less in the FPC 

 made after the fish had been stored for 11 days 

 than in the FPC produced after they had been 

 stored for 2 days. The concentration of histidine 



Table 5. — Amino acid composition of FPC prepared 

 from raw fish held in ice for periods up to 11 days. 



148 



