JOURNAL OF AGRICET1AL RESEARCH 



DEPARTMENT OF AGRICULTURE 

 Vol. VI Washington, D. C, September ii, 1916 No. 24 



PROGRESSIVE OXIDATION OF COLD-STORAGE BUTTER 



By D. C. Dyer, 

 Chemist, Dairy Division, Bureau of Animal Industry 



OUTLINE OF PREVIOUS WORK 



Much has been written concerning the changes occurring in butter. 

 The word "change" is here used in its broad and general sense to include 

 any perceptible alteration whatsoever, although it refers principally to 

 an organoleptic one, whether induced by one or several factors. 



Butter has been kept for certain periods of time during which it has 

 been exposed to the action of various decomposing and disintegrating 

 agencies, and a study of the products of change thereby resulting has led 

 investigators to draw conclusions relative to the causation of the "off 

 flavors" so often found in stored butter. As a general rule, the majority 

 of opinions advanced in accounting for the deterioration of butter seem 

 to have been based either upon insufficient analytical data or upon a 

 study of butter or butter fat kept under conditions which prevail only 

 to a very limited degree when butter is stored. 



Many investigators confined their attention to a study of the fat of 

 butter alone and sought to attribute the appearance of undesirable 

 flavors in whole butter to some change which this one constituent under- 

 goes. However, more recent investigations carried on with fats other 

 than butter would appear to render such an assumption doubtful and 

 would seem to make imperative more conclusive information concerning 

 the causation of disagreeable flavors in whole butter held in cold storage. 



The early literature in regard to the chemical changes which take place 

 in butter is voluminous, but it is also conflicting and confusing, a great 

 deal of it being of a purely speculative nature. 



A great variety of bodies, products of chemical change, have pre- 

 sumably been identified in butter kept under varying conditions. The 

 confirmation of the presence after a certain interval of time of such 

 substances in fats known to have been originally pure is of value; yet 

 such data obtained in the investigation of a material containing other 

 constituents as well are obviously not so satisfactory unless it is defi- 

 nitely known that these attendant components do not likewise undergo 



Journal of Agricultural Research, Vol. VI, No. 24 



Dept. of Agriculture, Washington, D. C. Sept. 11, 1916 



fi A-24 



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