MASS. EXPERIMENT STATION BULLETIN 182. 



CHEMICAL COMPOSITION AND DIGESTIBILITY. 



Table I. — Chemical Composition of Dry, Ripened Soy Beans. ^ 



Table I. plainly indicates the very high percentage of protein, 31.21 to 

 42.05 per cent., and of fat, 15.53 to 21.89 per cent., which compares with 

 beef (round steak), containing an average of 19 per cent, proteins and 

 12.8 per cent. fats. 



While it is a w^ell-estabhshed fact that these substances, namely, pro- 

 teins and fats, are essential materials in animal nutrition, the results of 

 recent investigations indicate that indi^Tidual proteins difi'er in their 

 digestibility and nutritive value, and that this difference is due to the 

 particular amino acids which they yield upon hydrolysis. The interpre- 

 tation, however, of such experimental results as have been thus far secured 

 is somewhat confused. In case of the soy beans, the digestibility of the 

 crude protein and fat is estimated at somewhere between 65 and 92 per 

 cent., and 70 and 80 per cent., respectively, by the different investigators, 

 such as Oshima,2 KeUner ^ and others. Although these figures may not 

 necessarily be indicative of actual food value, the relative merit of the 

 soy bean as human food is very significant. 



The author feels that there is still much to determine in the case of 

 vegetable and animal proteins, and that we have not yet reached the 

 stage in our knowledge where definite recommendations can be made. 

 Prauswitz'* conception, one of many, may have some bearing in the case 

 of this particular food, for the preparation of soy beans does seem to have 

 a distinctive effect upon their digestive and assimilative values. It is 

 possible that the fundamental differences in the nature of the nutrients, 

 or proteins, may be disregarded. The long-continued, successful use of 

 soy beans in oriental countries, over two thousand years, cannot be con- 

 sidered lightly in scientific interpretation. 



' M. Inouye: Bull. 2, 209, 1894-97, College of Agriculture, Tokyo, Japan. 

 * K. Oshima: Bull. 159, p. 191, 1905, U. S. Dept. of Agr., Office of Exp. Sta. 

 ^ O. Kellner: U. S. Dept. Com., Bur. For. and Dom. Com., Special Agents Series, No. 84, 

 Pt. I., p. 35. 



« Prauswitz: Ztschr. Biol., 35 (1897), p. 335. 



