16 



BULLETIN 330, U. S. DEPARTMENT OF AGRICULTURE. 



Table IV. — Size separation of samples of rice of the Honduras and Japan 

 types from various milling machines in modern mills. 





Average of 56 series of the Honduras 

 type of grains (per cent). 



Average of 25 series of the Japan type of 

 grains (percent). 



Milling stage. 

 / 



Whole. 



Three- 

 fourths. 



One- 

 half. 



One- 

 third. 



Less 

 than 

 one- 

 third. 



Whole. 



Three- 

 fourths. 



One- 

 half. 



One- 

 third. 



Less 

 than 

 one- 

 third. 



Paddy machine 



Hullers and pearling 



74.35 



52.51 



49.96 

 52.57 

 51.69 



8.76 



13.38 



13.56 

 14.62 

 14.44 



15.33 



24.73 



25.51 



26.28 

 27.18 



1.16 



5.67 



6.54 

 5.11 

 5.49 



0.40 



3.71 



4.43 

 1.42 

 1.20 



92.38 



84.22 



80.37 

 82.52 

 82.57 



2.38 

 4.30 



4.89 



4.84 

 4.70 



4.38 



7.66 



8.54 

 8.96 

 8.29 



0.65 

 2.44 



3.83 



2.88 

 3.61 



0.21 

 1.38 



Brush, brewer's rice: 



In 



Out 



2.37 

 .80 



Tnimhlfls 



.83 







The five points in the milling process at which these samples were 

 taken are considered very significant. The first is rice from the 

 paddy machine, and this shows the condition of the grain after the re- 

 moval of its hull in the stones and the separation in the paddy ma- 

 chine of the remaining portion of rough rice. This, then, is brown 

 rice, retaining the bran coat and germ nearly intact. Naturally, the 

 whole-grain content is comparatively large, but it has been found 

 that badly sun-cracked rice often shows a considerable amount of 

 breakage even at this point. 



The second line is rice from the hullers and pearling cone. Inas- 

 much as the pearling cone performs the same work in some mills as 

 is done by the hullers in others, the results are combined in the table, 

 so that the figures show the condition after the final scouring oper- 

 ation in each case, before the material goes to the brush. The severe 

 scouring which the grain undergoes in these machines is clearly 

 shown by the marked decrease in the percentage of whole grains 

 from that of the previous line. It is at this stage that most of the 

 breakage in rice milling occurs. 



The third line shows the rice after it has been scoured by the brush 

 and still contains all the small particles of brewer's rice. The fourth 

 line gives the percentage composition after most of the brewer's rice 

 has been removed in the brewer's reel. It is seen that the brush re- 

 duces the whole grain content only about 2^ per cent. On the other 

 hand, a small increase in the percentage of whole grains naturally 

 results from the removal by the brewer's reel of the fine particles of 

 brewer's rice. 



The last line shows the ungraded rice as it leaves the trumbles, 

 where it has been rolled and heated after having received in many 

 cases an application of coating materials. A slight breakage has 

 also occurred here. The rice grain normally is hard and brittle and 



