9 



rejjardiiirif the effects of cooking upon nutritive vsilue. and more espe 

 cially upon chemical composition and din-estil)ility, Init as a rule tiie 

 stuteuuMits are not accompanied by experimental data nor do the 

 generalizations always show evidence of being based upon careful 

 laboratory investigations. 



Many studies have been made with a view to ascertaining the 

 chemical structure of ditierent proteid bodies of animal and vegetable 

 origin, and at the present time many investigators are working along 

 these lines. The luiijority of the proteids studied, it seems fair to say, 

 are not those occurring in meats used as food, and the statement seems 

 warranted that up to the present time little is definitely known regard- 

 ing the chemistry of uncooked meats, and still less regarding the 

 complex changes brought about by different methods of cooking, 

 Wlmtever is known, however, is of great interest and value, not only 

 for itself but for the suggestions it offers for future lines of work. 



In 1895 Atwater" compiled and studied the results of investigations 

 on the changes brought about when meat and other foods are cooked. 

 The experimental data regarding the effects of cooking on the compo- 

 sition, digestibility, and nutritive value of foods were discussed, as 

 well as data regarding the losses resulting during the cooking of 

 meats, and also regarding the composition and luitritive value of broth. 



In Konig's'' extended compilation of data relative to the chemistry 

 of foods and food products, investigations are sununarized which have 

 to do with the cooking of food. That the amount of such data was 

 limited is shown by the fact that the summary covers only 16 pages. 



The results of a number of studies, most of them carried on by 

 American and English investigators, which add to our knowledge of 

 the changes which take place when foods are cooked, have been pub- 

 lished but are not included in either of the compilations just cited. 



The changes which take place in the carbohydrates when sweet 

 potatoes are baked was studied by W. E. Stone.'' 



Snyder, Frisby, and Bryant'' have reported determinations of the 

 losses of nutrients resulting in the boiling of potatoes, carrots, and 

 cabbage. Katherine I. Williams'' has studied in detail the chemical 

 composition of cooked vegetables as served at the table. Voorhees,/ 

 Isabel Bevier,^' Snyder,''' and Woods*' have published results of investi- 

 gations showing the losses involved in the process of bread making. 



«U. S. Dept. Agr., Office of Experiment Stations Bui. 21, p. 91. 



b Chemie der Mensclilichen Nahrungs- und Genussmittel. 4. ed., vol. 2, p. 1244. 



cBer. Deut. Chem. Gesell., 23 (1890), p. 1406; Agr. Sci., 14 (1890), p. 31. 



<^U. S. Dept. Agr., Office of Experiment Stations Bui. 43. 



«Jour. Amer. Chem. Soc, 26 (1904), p. 244. 



/U. S. Dept. Agr., Office of Experiment Stations Buls. 35 and 67. 



S'U. S. Dept. Agr., Office of Experiment Stations Bui. 52. 



^U. S. Dept. Agr., Office of Experiment Stations Buls. 67, 101, and 126. 



^U. S. Dept. Agr., Office of Experiment Stations Bui. 85. 



