FISHERY BULLETIN: VOL. 69, NO. 1 



at — 20° C (The other cartons were used in 

 another experiment.) The hake were used with- 

 in 1 month after storage. 



About 17 to 18 hr before studying each pro- 

 cessing variable, we placed one carton of fish 

 in a refrigerated room at a temperature of 5° 

 to 6° C. This treatment allowed the fish to thaw 

 sufliciently so that they could be handled indi- 

 vidually. The fish were ground through a Ho- 

 bart meat grinder," which was equipped with an 

 end plate containing holes that were one-quarter 

 inch in diameter. After the hake were ground, 

 they were thoroughly mixed, and a sample that 

 weighed 20 lb was removed. The sample was 

 divided into three equal portions, and each por- 

 tion was placed in a 2-inch-deep tray lined with 

 aluminum foil. (This procedure was used in 

 order to permit existing equipment to be used.) 



The trays were placed in an autoclave and 

 were heated at 100°, 109°, or 121° C for 10, 

 20, 40, or 80 min. Thermocouples were used to 

 measure the temperature of the samples. After 

 being heated, the trays were removed from the 

 autoclave, were covered with aluminum foil, and 

 were cooled in a refrigerated room at 5° to 6° C. 

 A control sample was also prepared, which con- 

 sisted of raw, unheated ground hake. 



The entire contents of the trays were mixed 

 with solvent at a 2:1 (w/w) ratio of solvent 

 to solid. The samples were extracted by the 

 "cross-current" batch-extraction procedure de- 

 scribed by Brown and Miller (1969). The 

 solvent used for extraction was 91 % , by volume, 

 isopropyl alcohol. 



The extracted and dried samples of FPC were 

 ground in a Rietz Disintegrator. 



The samples were analyzed for crude protein, 

 volatiles, and ash by the methods described by 

 Horwitz (196.5). Lipids were determined by 

 the method of Smith, Ambrose, and Knobl 

 (1964). 



Table 1 shows the concentrations of crude 

 protein, ash, and lipids found. 



The concentration of crude protein in the 

 samples that were heated was slightly lower 

 than in the sample that was not heated. The 



Table 1. — Proximate composition, expressed on a mois- 

 ture-free basis, of samples of FPC prepared from hake 

 that were heated for var>'ing times and temperatures 

 before being extracted with solvent. 



' The use of trade names is merely to facilitate de- 

 scriptions; no endorsement is implied. 



concentration of crude protein, however, was 

 not significantly affected by the temperature at 

 which the samples were heated. Also, the time 

 of heating did not significantly aflFect the con- 

 centration of crude protein in the samples, 

 except for the 20-min treatment. The samples 

 that were heated for 20 min had a slightly low- 

 er concentration of crude protein than did those 

 that were heated for the other intervals of time. 



The concentration of ash was slightly higher 

 in the samples that were heated than in the 

 sample that was not heated. The concentration 

 of ash in the heated samples was not afl!'ected 

 by either the temperature of heating or the 

 length of time of heating. 



The concentration of lipid in the samples was 

 somewhat variable, but it was not significantly 

 affected by the treatments. 



AMINO ACID COMPOSITION 



Es.sential amino acids, excejjt for tryptophan, 

 were determined with an automatic amino acid 

 analyzer by the method described by Moore, 

 Spackman, and Stein (1958). Tryptophan was 

 determined chemically by the method of Spies 

 and Chambers ( 1949) . Cystine was determined 



142 



