THE BY-PRODUCTS OF RICE MILLING. 15 



In the calculated analyses given in Tables 8, 10, 12, and 14, for the 

 mixed brans as they would ordinarily appear on the market, the ash 

 in all cases was 10 per cent or less, the insoluble ash in all cases was 

 below 5 per cent, and the fat plus protein ranged from 26.7 per cent 

 to nearly 30 per cent. The crude fiber was always above 10 per cent, 

 a figure considered by many chemists to be the limit for a pure rice 

 bran. The nitrogen-free extract approximated 40 per cent. This 

 figure, however, seems to be of little use in determining the char- 

 acter of the product, except that in some cases a high figure may 

 confirm the presence of a large amount of broken rice. 



The results show that rice polish is characterized by very low acid- 

 insoluble ash, by low crude-fiber value, and by high nitrogen-free 

 extract. It should have a fat plus protein content above 20 per cent. 

 The rice polish in lot D was somewhat abnormal for the reason 

 that, on account of the light milling to which the rice had been sub- 

 jected, the portion taken off in the brush machine consisted in part of 

 the material which usually would be taken off in the second-break 

 hullers. 



ALL SAMPLES. 



A consideration of the chemical results on all samples taken shows 

 that all the rice hulls examined were very high in both ash and fiber 

 and were of such low protein and fat content as to have practically no 

 feeding value. In addition, their physical structure renders them 

 harmful to animals if fed in too large amounts. 



The stone-reel bran was uniformly much higher in total ash, acid- 

 insoluble ash, and crude fiber, and was lower in protein and fat than 

 were the huller brans. This was due to the presence of the hulls 

 which entered the stone-reel bran after they had been broken up by 

 the stones. The analysis of this by-product would indicate that 

 usually it contains from 25 to 50 per cent of hulls. The huller brans 

 were nearly all very low in fiber and acid-insoluble ash, showing their 

 comparative freedom from hulls, and were high in protein and fat. 

 Their composition would make them a very rich feeding stuff if used 

 alone. At present, however, huller brans are not used for feeding 

 purposes, partly for the reason that they do not keep well and partly 

 because millers always have made a practice of including the product 

 of the stone reel in their bran. This mixture is the bran as com- 

 monly found on the market and contains an amount of hulls from the 

 stone-reel bran which would seem to add materially to the keeping 

 qualities of the product, and at the same time to give a feed acceptable 

 to the consumer. This product, when produced under known condi- 

 tions that preclude the addition of ground hulls, should contain over 

 26 per cent fat plus protein. It should not exceed 13 per cent of 

 crude fiber or 5 per cent of ash insoluble in hydrochloric acid. 



