1909.] PUBLIC DOCUMENT — No. 31. 27 



Sour and Colored Gluten Feeds. 



BY P. H. SMITH. 



Gluten feed is, excepting the germ, the residnal ]n'oduct in 

 the manufacture of starch and glucose from corn. It is used 

 extensively in dairy rations, its sales being probably second 

 only to those of the wheat by-products. During the past season 

 considerable agitation has been caused by the condition of cer- 

 tain shipments of gluten feed, which had not only a decidedly 

 acid taste but were found upon examination to have been col- 

 tored with an aniline dye. The experiment station has, through 

 Mr. P. V. .Goldsmith, made a somewhat extended investigation 

 of the gluten feed found on the Massachusetts market, both as 

 to acidity and coloring.^ Some lots of feed were, if at all, only 

 slightly sour ; others were so sharply acid to the taste as to be 

 considered unpalatable. As a very dilute solution of sulfurous 

 acid is used to soften the corn before separating the starch, it 

 seemed probable that the sour taste was largely due to this acid. 

 On examination, however, it was found that neither sulfurous 

 nor sulfuric acid was present in sufficient quantities to account 

 for all the acid found. In the light of the evidence now at hand 

 it is believed that the acidity is due principally to the salts 

 of phosphorus, and that sulfurous acid and the sulfites are 

 present in such minute traces as not to be considered harmful. 

 It is not thought that the amount of acid present is in any way 

 injurious to animals. It is believed, however, that a more 

 satisfactory product would result if, before placing on the mar- 

 ket, the feed were treated in such a way as to leave only a 

 minimum amount of acid evident to the taste. 



Coloring Matter. — Some 80 per cent, of the gluten feeds on 

 the market were fonud to be artificially colored with an aniline 



1 See Pnrt II, of the report of this station, published under separate coyer. 



