on the quality of tuna canned therefrom. During the field survey of the 

 industry, many conments had been made by processors regarding the import- 

 ance of this stage of the processing in obtaining the maximum yield. 

 Opinions varied as to the effect on the quality of the pack of shorteipjig 

 the pre cook. 



Albacore, cau^t about August 1, 1952, in waters off the coast of 

 Oregon and held since that date in cold storage at 0° F., were used for 

 this experiment carried out on November 17, 1952. Ei^t fish ranging 

 from 11.5 to 15.5 pounds and averaging 13.3 pounds were thawed and 

 butchered. Three fish were precooked for what was estimated to be nor- 

 mal precooking time (2^ hours at 218° F,), three were cooked for one-half 

 of the normal time (l^ hours at 218° F,), and two fish were not cooked 

 at all. All three batches were thai cleaned, packed with oil, and pro- 

 cessed in the usual way. Fish were sampled at various stages, weired, 

 and protein, moisture, and oil content were determined. 



Butchering losses amounted to only 2.8 percent. The loss of 

 weight brought about by precooking (before cooling) amounted to 14.4 

 percait (based on the total weight of the fish) for the half normally 

 cooked fish and 16,1 percent after normal precooking period. The total 

 losses (occurring during cooking and cooling) were 17.3 percent and 19.9 

 percent respectively. 



In tables 74, 75, and 76 are shown the protein, moisture, and oil 

 content of the fish. Analyses are shown for the precooked fish before 

 addition of oil or salt and for the final canned fish after draining 

 away the oil. Each figure in these tables represents an average of values 

 fr5m siXi Number i tuna cans. In table 77 is shown the amount of fluids 

 (aqueous phase and oil) drained from a No. 5 tuna can receiving different 

 degrees of precook and the amount of dissolved solids in the aqueous 

 phase of such fluids. Here again values reported are averages of data 

 obtained from six cans of fish. 



The protein contait of drained tuna, determined before retorting, 

 rose frcm 22.4 percent for \incooked fish to 28.1 percent for fish given 

 the fun precook time (table 74). This difference is not nearly so 

 great after the fish had been retorted, an increase of from 26.1 percent 

 (no precook) to 27o5 percent (normal precook) occurring for the same 

 samples. The final retorting, being a much more drastic process than 

 the precook, tends to equalize differences due to the degree of precook. 



317 



