the Columbia River and has since spread to Puget ^ound and Alaska. 

 The process used for the preparation of the oil has consisted of the 

 following steps: 



1. Pressure cooking of the raw material. 



2. Segregation of liquors from solids by settling and/or screening. 



3. Separation of the oil from the liquor by centrifugation. 



4. Storage of finished oil in tin containers. 



In connection with the utilization of Alaska salmon cannery waste, 

 one possible use for a portion of the offal would be the preparation 

 of an edible or canning grade oil similar to that new being used. Since 

 the visceral portions of the waste lend themselves to alkali digestion 

 in the preparation of a vitamin A oil, the head and collarbone section 

 of the offal vras utilized to prepare canning oil by the same method. A 

 series of packs of the five species of salmon were prepared to evalu- 

 ate arid compare any changes in the odor and flavor attributable to the 

 added salmon oil. The effect of salmon oil prepared by the alkali 

 digestion process was also compared with the salmon oil prepared by 

 boiling the heads. 



Selection of Raw ^teriaO. 



The salmon heads were collected at the header machine just before 

 the decapitated fish is sent to the "Iron Chink" for the balance of 

 the butchering operation. The severed head usually contains a small 

 part of the liver and possibly the heart. The heads were washed thoro- 

 u^ly by spraying them with high pressure salt water from a hose, after 

 which they were re-washed in potable water. Slime and blood were re- 

 moved in this washing operation » 



Material was collected in lots of approximately 200 pounds for 

 each of the five species of salmon. Each of these lots was divided 

 into two equal parts. One hundred pounds of heads from each lot were 

 processed into oil by the alkali digestion method. The other hundred 

 pounds were processed by boiling the heads at atmospheric pressure. 



Equignent Used for Alkali Digestion 



The digester used was a wooden barrel approximately 30 inches in 

 diameter and 42 inches in height. A piece of iron pipe, l/2-inch in 

 diameter, was bent in a semi-circle to conform to the shape of the bottom 

 of the barrel. This pipe was then placed in the bottom of the barrel 

 and connected, by means of a second vertical pipe and a hose, to a source 

 of high-pressure steam. A portable stirrer unit, powered with one- 

 quarter horeepower 1750 RPM direct-drive motor and equipped with two 



90 



