529 



(1) Tho (lip;estibility of the nitrogenous materials is considerably 

 decreased by the bakiiii;- process. Tlie nitrogenous materials of the 

 crust are more difticult of digestion than those of the "crumb," or 

 interior i)ortion. 



(2) HCl without ])epsin dissolves the nitrogenous substances of tiour 

 to a very considerable degree, but is almost without action on those of 

 baked bread. 



(3) Water alone dissolves about four tiuies as much of albuminoid 

 materials from flour as from alike amount of bread. 



3. Pea-nut cale. — The previous experiments were made with mate- 

 rials rich in carbohydrates and relatively poor in fat and protein. To 

 test the action of a material containing more protein and fat, experi- 

 ments were made with pea-nut cake. Previous lo the digestion trials, 

 the cake was in some instances heated either in ordinary air, in dry air, 

 or in dry carbon dioxide at 90-97° C, and in otluus in boiling water. 

 The result of these trials led to the following conclusions: 



(1) The albuminoids contained in pea-nut cake are rendered difficultly 

 soluble in water by the action of either moist or dr^^ heat. 



(2) Very dilute hydrochloric acid (0.05 per cent) has very little sol- 

 vent action on the albuminoids after the pea-nut cake has been cooked in 

 water. Dry heat made little if any change in their solubility in HCl. 



(3) The albuminoids were less soluble in acid pepsin solution after 

 being subjected to dry heat or cooked in water than before this treat- 

 ment. 



The above experiments all go to show that the albuminoids of vege- 

 table substances are rendered less digestible by drj- heating and by 

 cooking in water. 



Does the presence of small quantities of fat or oils in foods retard the 

 digestion of the albuminoid materials '? — It is well known that large quan- 

 tities of fat impregnating a food may mechanically hinder the digestion 

 of the albuminoid materials, and the object of the author was to ascer- 

 tain if the quantities contained in ordinary oil cakes are sufficient to 

 present such mechanical hindrance. The experiments were made on 

 cotton seed meal containing 9 per ceut fat, and cocoanut cake contain- 

 ing 15 per cent fat. Samples of these materials in their original condi- 

 tion (before the extraction of the fat), and after the fat had been 

 extracted by ether, were treated with water alone, with water containing 

 0.05, 0.1, and 0.2 per centHGl, and with pepsin solution containing the 

 same percentages of HCl, the amount of substance taken for each 

 test being such as to furnish 100 mg. of pepsin -soluble albuminoid 

 nitrogen. 



The results indicated that the fat presented a slight hindrance to the 

 action of water and of IIOI, but tlie difference between the amounts of 

 albuminoid nitrogen dissolved by acid pepsin solution from the material 

 treated with ether aud that in tho original state were so small as to be 

 ■within the allowable error of analysis. The author regards it, there- 



