8 



the cooking of meats upon their total dig-estibility, and upon the ease 

 and rapidity of their dig-estiuii, ard the results obtained, which have 

 been described in part," it is expected will soon appear in full as a 

 bulletin from this Office. 



During- the year 1903-4 the methods used in these studies have been 

 in a number of ways materially extended in scope and moditied in 

 form. The plan of the investigations has also been extended with a 

 view to studying as completely as possible the influence of different 

 methods of cooking upon the nutritive value of meats and the charac- 

 ter of the physical and chemical changes which take place in meats 

 when they are cooked by various common methods. It is the object 

 of this bulletin to describe this work and to give in detail some of the 

 results which have so far been obtained. 



The work here reported includes (1) thirty-one experiments made 

 to determine the amount of the losses which result in the cooking of 

 meats in hot water at different temperatures and for different lengths 

 of time, a special feature being a detailed study of the nature of 

 the nutritive constituents of the meats before and after cooking; 

 (?) four experiments to estimate the amount and character of the 

 losses which take place when meats are cooked by pan broiling 

 and at the same time to find out the relation existing between the 

 nutritive value of the raw^ and that of the cooked meats; (3) three 

 experiments to find what losses and changes in nutritive value result 

 when meats are cooked by roasting; (4) six experiments to determine 

 the losses and also the changes in nutritive value which meats undergo 

 when they are cooked by sauteing, frying, gas broiling, and pot roast- 

 ing; (5) three experiments to show the influence of the different meth- 

 ods of cooking meats upon flavor and palatability, and (6) four experi- 

 ments to determine the amount and nature of the substances which 

 bones yield when cooked in hot water, as in making soup. 



HISTORICAL REVIEW. 



A review of chemical literature shows that many studies of the 

 changes brought about in various proteids, fats, and carbohydrates by 

 oxidation by heat or otherwise, and by treatment with water under 

 pressure or other methods of hydration and by the action of different 

 reagents have been undertaken which, properly considered, would 

 throw light on the changes brought about by cooking. But appar- 

 ently no attempt has as yet been made to collect and digest this widely 

 scattered material. An extended search of the literature of the sub- 

 ject indicates that comparatively few experimental investigations have 

 been undertaken with the direct object of studying the chemical, histo- 

 logical, and other changes which different foods undergo during the 

 process of cooking. Considerable has been said by different writers 



"Univ. 111., Univ. Studies, vol. 1, No. 5, p. 1. 



