16 



Teller points out that about 87.5 per cent of the entire phosphoric 

 acid, 78.5 per cent of the potash, and 37.5 per cent of the nitrogen 

 present in the wheat berry are recovered in the milling products 

 ordinarih' used as cattle feeds. As will be seen from the above table, 

 the percentage of phosphoric acid increases as the grade of flour 

 decreases, being least in the patent flour and greatest in low-grade 

 flour, the proportion present in the latter being greater than in any of 

 the milling products except ship stufl"; in other words, as shown by these 

 figures, the phosphoric acid content, generall}^ speaking, increases in 

 passing from the center of the wheat berry to the outer layer, the 

 inner portion yielding the fine flour and the outer portion the bran. 

 The table also shows that in the various milling products the propor- 

 tion of nitrogen (and hence that of protein, since the latter is computed 

 b}^ multiplving nitrogen by a constant factor) varies in practically the 

 same way as the phosphorus. 



The parallelism between protein and phosphorus, which was spoken 

 of above, is borne out by the analytical data quoted, though it does 

 not necessarily follow that the phosphorus present occurs in the true 

 proteids. 



As a whole, it has been the aim in the experiments conducted at the 

 University of Minnesota to include standard t3'pos and varieties of 

 hard and soft wheat flours, milled under different conditions. The 

 difl'erences in the percentages of flour recovered from the wheat used 

 necessarily make slight diflferences in the composition and character- 

 istics of the grades of flour obtained. The soft wheat products were 

 of different character from the samples of similar products from hard 

 wheat. The hard wheats had been exhaustively milled, as is the 

 usual custom, in one of the large mills of Minneapolis, while the soft 

 winter wheats were ground by mills of smaller capacity using some- 

 what different milling svstems, and, as is the general commercial prac- 

 tice, were less exhaustively milled. 



In general, the flours Trom soft wheat were somewhat similar to, 

 though not in every respect like those from, hard wheat, because of 

 the differences in the kinds of wheat used and percentages of flour 

 recovered. The graham flour contained the largest percentage of pro- 

 tein, fat, and ash, while the patent grades of flour contained the small- 

 est amounts of these ingredients. A noticeable difference in the 

 mechanical composition of the three grades of soft wheat flour was 

 observed. With the process of milling followed, some granular mid- 

 dlings were left in the offals which would have been recovered in the 

 straight and other grades of flour with more exhaustive milling. This 

 results in a straight-grade flour containing slightly less protein than 

 the product of exhaustive milling, as the granular middlings are rich 

 in this nutrient. The particles or granules of the graham flour were 



