456 THIAMINE 



In the modern milling machines (high milling) the process can be regu- 

 lated in such a way that several fractions are obtained corresponding to 

 the different layers of the kernel. For the preparation of white bread usually 

 a fraction is taken that contains all the endosperm plus so much of the 

 other parts that about 70 % of the kernel is present in this fraction. We call 

 this a 70 % extraction flour. The thiamine content of this flour is about 60 

 7 per 100 g. In wartime in England, Holland, and in several other countries 

 a flour of about 85 % extraction was used for bread making. The thiamine 

 content of this fraction was about 240 7 per 100 g. 



In the process of bread-making yeast is added, so that the thiamine con- 

 tent increases somewhat, but because of the high baking temperature part 

 of the thiamine, especially in the crust, is destroyed. White bread contains 

 approximately 40 7 of thiamine per 100 g., whole meal bread about 180 

 7, and the 85 % extraction war bread about 120 7. To the "enriched" bread 

 so much synthetic thiamine has been added that the total thiamine amounts 

 to 110 to 180 7 per 100 g. 



(2) Rye. Rye bread usually is made of the whole kernel. Sometimes flour 

 is used. The thiamine content of rye bread is somewhat lower than that of 

 the corresponding wheat bread. 



(3) Rice. The thiamine content of rice is lower than that of wheat, namely 

 about 300 7 per 100 g. In home-pounded rice, most of the thiamine remains. 

 In machine-milled rice, only about 30 7 per 100 g. is left. Rice is always 

 thoroughly washed before cooking. This reduces the thiamine content still 

 further. 



In the native process of parboiling, the rice is first soaked in water, then 

 boiled and dried. This product is milled. The resulting parboiled rice con- 

 tains nearly all the thiamine of the whole rice kernel. About the same proc- 

 ess is used in industry for the preparation of "converted" rice. This also 

 contains nearly all the thiamine of the original rice. "Enriched" rice con- 

 tains about 500 7 of thiamine per 100 g. 



(4) Corn. The thiamine content of corn is not very high. Its chief de- 

 ficiency is that of niacin and tryptophan. Therefore, pellagra is the disease 

 of the corn-eating countries. However, in some cases of pellagra clinical 

 signs of a thiamine deficiency may be found. For the prevention and ther- 

 apy of pellagra an extra addition of thiamine, besides niacin, is necessary. 



6. Legumes 



Peas and beans are among the foods richest in thiamine. They contain 

 about 500 to 600 7 of thiamine per 100 g. After the discovery that beriberi 

 was caused by the use of polished rice, "katjang idjo," a kind of green peas, 

 was employed in the prevention of beriberi.* 



Soybeans are just as good a source of thiamine as the common pulses. 



