68 



DB. EUTTAN ON THE 



power of the mixture must, however, be a concise expression of the relative diastatic action 

 of the ferment in each case. 



The percentage of starch converted into reducing bodies is calculated according to the 

 following reaction : — 



4 C,H,A + 3 H,0 C,H,A + 3 CJI.X), 



Starch, Dextrin, Dextrose, 



i.e. 6 parts of starch yield 5 parts of dextrose by eight. 



Series III. — Tlie Relative DigeslibiHiy of Breads made jnth Different Baking Poivders and Plain 



Unleavened Bread. Salivary Digestion. 



Table 1. 



In these experiments 1 gramme of dried bread was taken in powder, reduced to a pulp, 

 as in Series II, with 5 c.c. of water, 2 c.c. of filtered saliva added, and each mixture 

 made up to 50 c.c. After digesting for thirty minutes and being boiled to kill the ferment, 

 the mixture was filtered ; the filtrate and washings were then made up YS c.c. and the 

 dextrose estimated by Fehliug's solution. 



There is no other ferment of the digestive tract so susceptible to the influence of 

 foreign substances as ptyalin. Chittenden, Smith and Painter, of Yale College, who 

 studied the action of many therapeutic and toxic salts on ptyalin, found that many neutral 

 salts, even in minute traces, would delay or even stop the amylolytic action of saliva, while 

 not a few salts tend to accelerate the ferment action." 



It seemed, therefore, probable that any retarding influence possessed by the salts in 

 these baking powders would be especially marked in the case of the amylolytic ferment of 

 saliA^a. 



A comparison of Table 6 (Series II) with the foregoing, shews this to be the case. 

 In th» former, the amylolytic ferment of the pancreas converted 26% of the starch in the 

 plain bread against 27 % converted by the ptyalin ; yet in the latter there was about 3 % 

 less starch converted in the case of each bread containing the powders. 



From the experiments detailed in Division A, one may conclude : — (1) That of the forms 

 of bread experimented on, yeast bread and plain flour and water are the most digestible, 



' Trans. Conn. Acad., vol. vi, March, 1885. 



