BUREAU OF CHEMISTRY. 225 



manufacturers, all of whom exhibited eagerness to cooperate and to 

 offer every facility to promote the work. Laboratory investigations 

 were undertaken to compare the nutritional qualities of dried products 

 with those of canned and fresh material. About 30 departments of 

 home economics, mostly in the agricultural colleges, cooperated, thus 

 making it possible to reach conclusions more speedily than could have 

 been done had the w^ork been confined to a single laboratory. Studies 

 on the nutritional value of dried products were also undertaken at 

 Johns Hopkins University and at the University of Rochester. On 

 the whole, the findings have been quite favorable. 



Studies have also been made to determine the best conditions for the 

 storage of dried products, especially the most suitable types of con- 

 tainers, and an mvestigation of the flora of such products is in 

 progress. Bulletins bearing on the various phases of the dehydration 

 work, now in preparation, should appear during the coming year. 

 Two general addresses by those in charge of the work have been pub- 

 lished, one of them as Office of the Secretary Circular 126, " Relation 

 of Dehydration to Agriculture." The net result of the work has been 

 of real practical assistance to the industry. Poor materials are dis- 

 appearing from the market, and a few plants producing materials of 

 excellent quality liave become established. 



In cooperation with a plant in South Carolina, an attempt was 

 made by tlie bureau to produce sweet potato flour by the methods 

 used with success in the production of white potato flour. The plant 

 was operated for a few months, but the results were disappointing 

 because of the very hygroscopic nature of the product which in- 

 fluenced unfavorably its keepmg quality. The data will be pub- 

 lished. The bureau has also been able to assist in the establishment 

 of the white potato flour industry, which seems to be gaining ground. 

 Data on potato flour and potatg bread have been published. 



Cooperation with the potato starch industry is in progress, looking 

 toward the utilization of potato pomace, improvement of the meth- 

 ods for drying starch, the production of potato dextrin, and an in- 

 crease in the capacity of tne plants. Assistance was given to the 

 Office of the Quarterjiiaster General in the inspection and supervision 

 of plants producing dehydrated vegetables for the Army. 



FLOUR AND CEREALS. 



Department Bulletin 701, "The Chemical Analysis of Wheat- 

 Flour Substitutes and of the Breads Made Therefrom," has been 

 issued, and a paper on the composition and baking value of the dif- 

 ferent sized particles of flour is in press. 



As it was proposed during the year to import from Australia 

 wheat badly infested with w^eevils, experiments were performed to 

 determine the degree to w^hich wheat may be heated in the attempt 

 to destroy the w^eevils without affecting the quality of flour pro- 

 duced from the treated wheat. It was found safe to heat to 160 F., 

 but not to 180 F., for 30 minutes. 



Rice is one of the flour substitutes employed during the war which 

 promises to continue to be used in baking. Baking experiments, 

 therefore, were made w^ith flour prepared from different varieties and 

 grades of rice, polished to varying degrees. Fifteen per cent of 

 rice and 85 per cent of white flour were used. No appreciable dif- 



