BUREAU OF CHEMISTRY. 347 



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growth and development. Some of the vegetable proteins are de- 

 ficient in these essential amino acids. Therefore a knowledge of the 

 constituents of the vegetable proteins is essential to a knowledge of 

 nutritional requirements and the value of our food materials. 



During the year the ph3'sical and chemical properties of various 

 proteins were determined. The cystine and tryptophane content of a 

 large number of proteins is being determined. A study on the nu- 

 tritive deficiency of arachin, which is the chief protein of the pea- 

 nut, is in progress. Peanut meal, when fed to animals as the sole 

 source of protein, has an unusually high degree of efficiency. 



A study of the proteins of wheat bran is in progress. When this 

 Avork was begun practically nothing was known regarding the chemi- 

 cal or phj^sical properties of the proteins of wheat bran, notwith- 

 standing the fact that 22 per cent of the total protein of the wheat 

 kernel is in the bran. Bran has long been regarded by practical 

 feeders of farm animals as having high nutritive value, and it has 

 been considered that the proteins of wheat bran are superior in 

 nutritive quality to those of the endosperm. Nearly 66 per cent 

 of the total protein in the bran has been isolated and identified. 

 The chemical properties and composition of these proteins have 

 been studied. A study of the nutritive value of the proteins of the 

 lentil has been made. 



A critical study of the amino acids in the hydrolysis products of 

 glycinin, the chief protein of the soy bean, is being continued. Special 

 attention is being paid to the development and improvement in the 

 methods and technique involved in the quantitative determination 

 of amino acids. There is under way a study of the proteins of cacao 

 beans and also a chemical study of the proteins of cottonseed. Anal- 

 yses of several preparations of the cottonseed globulin liave been 

 made. In a study of the proteins of the navy bean, a hitherto un- 

 known globulin, which has been called conphaseolin, has been 

 isolated. The chemical properties of this globulin have been deter- 

 mined and analyses to determine the percentages of the nutritionally 

 essential amino acids have been made. 



A paper on " The nutritive value of mixtures of proteins from 

 corn and various concentrates," in the Journal of Agricultural Re- 

 search, shows that the proteins of peanut meal, soy-bean meal, coco- 

 nut press cake, and tomato-seed press cake contain, in sufficient 

 quantity to supplement satisfactorily the corn proteins, the amino 

 acids which are lacking in corn. The various proportions of con- 

 centrate to corn which were used and found satisfactory for the 

 normal growth and development of animals are reported. 



VEGETABLE OILS. 



In nutrition the fats and oils are second in importance only to 

 the proteins. Through the application of chemistry to the refining 

 of crude products and to the so-called hardening (hydrogenation) 

 of vegetable fats there has been a tremendous development in the 

 utilization of vegetable oils — a profitable development for the farmer 

 and planter, which has added millions to our national wealth. Such 

 research work is of no less importance to the consuming public in 

 making available a nutritious and cheap food. This development 

 has been dependent almost wholly upon agricultural chemical re- 

 search. 



