Potato Studies. 



21 



POTATO POMACE 



Potato pomace is the residue which is left in the manufac- 

 ture of starch from potatoes. The process in general use in 

 this country and Europe briefly stated is as follows : 



The tubers after being thoroughly cleansed of all dirt are 

 placed in iron grinding cylinders with saw teeth which lacerate 

 the cells, setting the starch granules free. The ground mass is 

 then washed with cold water on sieves placed over tanks, the 

 starch granules pass through and settle out in the bottom of 

 the tank while the pulp passes off with another portion of the 

 wash water. 



The drained pomace carries about 90 per cent of water 

 while potatoes carry less than 80 per cent. 



Table Showing the Analysis of Potato Pomace and Potatoes 





Water 



Dry 



matter 



Ash 



Protein 



Fiber 



Pat 



Nitrogen 



free 

 extract 



On fresh basis 



% 



% 



% 



% 



% 



% 



% 



Pomace 

 Potatoes 



93.0 

 78.7 



10.0 

 23.3 



.3 



.9 



.8 

 3.2 



1.1 



.6 



.1 

 .1 



7iV 

 18.5 



On water-free (dry) 

 basis 

















Pomace 

 Potatoes 





100.0 

 100.0 



3.1 

 3.6 



7.8 

 9.5 



11.4 

 2.7 



.6 

 .1 



77.1 

 84.1 



The increase in fiber, loss in water soluble protein matter, 

 and the consequent changes in nitrogen-free extract are the 

 principal differences between the potatoes and the pomace. 

 These differences are more clearly shown on the water- free 

 basis. 



As this pulp residue all goes to waste in this country the 

 process is necessarily a wasteful one, and manufacturers have 

 been giving some thought to devising a method of recovering 

 it. The chief obstacle to its use in the fresh condition is the 

 large amount of water it contains. If some method could be 

 devised for cheaply removing the larger part of the water, the 

 dry matter would have considerable value as a feeding stuff. 

 Of course, the material could be fed with 80 to 90 per cent of 

 water present, but in this condition it would keep but a short 



