RECENT WORK IX A(;RICliETURAL SCIENCE. 



CHEMISTRY. 



The action of enzymic ferments upon starches of different 

 origin, AV. E. STO^■E {U. IS. JJept. Ayr., Office of Experiment Siations 

 Bui. 34, pp. 39— U). — The author refers to the differences which have 

 been noticed between starclies from various phints. He reports studies 

 made to compare the susceptibility of ditfereut starches to a number of 

 enzymic ferments, viz, diastase, saU\ary enzyms, pancreatic euzyms, 

 and "Taka-diastase/' Tlie starches were freshly prepared from maize, 

 wheat, rice, potatoes, and sweet potatoes. They were gelatinized by 

 heating- in water. Varying amounts of starch were treated with solu- 

 tions of the enzyms of different strengths, and the time noted which 

 was required for complete solution or saccharihcation, as showu by the 

 iodin reaction. 



The following conclusions were reached: 



"(1) The starches of jtotato, sweet potato, maize, rice, and wheat vary jiieatly iu 

 their susceptibility to the action of cuzyiiiic feriueiits. 



"(2) This variation reaches such a degree that uuder precisely the same condi- 

 tions certain of the starches reiiuire eighty times as long as others for complete 

 solution or saccharification. 



"(3) This variation is exhibited toward all of the common enzymic ferments 

 studied, viz, diastase, ptyaliu, pancreatin, and "Taka-diasta.se," in the same rela- 

 tive order, with slight exception. 



"(4) Tins order, beginning with the starch which is most easily changed, is, for 

 malt extract — sweet potato, potato, wheat, and maize; for saliva — potato, sweet 

 potato, maize, rice, and wheat; for jiancreatic Uuids — potato, sweet potato, maize, 

 with wheat and rice nuchaugeil; for 'Taka-diastase' the potato was more (j[uickly 

 changed than any other. 



•'(5) Certain of the experiments indicate that the rapidity of the change iu par- 

 ticular cases is very clearly projiortional to the concentration of the solution ol the 

 ferment. 



"(6) It seems reasonable to assume that the same relative degree of snsceptibility 

 exhibited by these starches iu the experiments described would still obtain when 

 they are subjected to the action of the same euzyms in the i^rocesses of digestion. 



"(7) The facts here presented have very important bearings upon industrial oper- 

 ations involving the use of starches, upon questions of physiology and untrition, 

 and upon the study of the ditferent starches from the purely scientific standpoint." 

 662 



