8 BULLETIN 323, U. S. DEPARTMENT OF AGEICULTUEE. 



In studying the protein of the various types of rice many factors 

 seem to be of importance. Chinese white rice, which has a very 

 small and very flinty kernel, contains in a water-free sample 9.17 per 

 cent of protein; and Patna rice, which shows indications of severe 

 milling, also has a high protein content. The climatic and, possibly, 

 the soil conditions under which rice is grown seem to exert as great 

 an influence upon the quantity of its protein as does the method or 

 severity of milling. By comparing the protein content of the first 

 with that of the second subdivision of the Japan rice type, as shown 

 in Table III, it is seen that only 0.64 per cent of this constituent is 

 scoured off in the process of milling. Even though the milling of 

 rice does not remove the major part of its protein, as is commonly 

 supposed, there is in the milling of a given quantity of the grain a 

 total loss of this expensive food constituent which should be con- 

 sidered. Completely milled rice can not be regarded as a balanced 

 ration, simply because a large part of the original protein remains in 

 the starchy endosperm of the kernel after milling. In judging a food 

 the protein content is, of course, an important factor, but it must be 

 considered in connection with various other important factors, such 

 as ether extract and, to a less extent, ash. As previously mentioned, 

 the milling of rice reduces its ash content very materially, and the 

 ether extract, the greater part of which is in the germ of the kernel, 

 is decreased from over 2 per cent to about 0.2 or 0.3 per cent, which 

 is almost a negligible quantity. The slight losses in protein and in 

 minute quantities of a substance called "vitamine," together with 

 the very great loss in ether extract and ash, which result from the 

 modern methods of milling rice, tend to greatly lessen its food value 

 and to yield by-products containing large quantities of valuable 

 constituents of human food. 



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