CONVERSION OF RAW STARCH INTO STARCH-PASTE, ETC. 95 



Since the investigations of Musculus, Griessmayer, Briicke, 0'Sulli\'an, and Mus- 

 cuhis and Gruber, a very volimiinoiis literature lias accimiiilated which treats, in a large 

 measure, of soluble starch, amylodextrins, erythrodextrins, achroodextrins, and the sac- 

 charine products; and also much bearing directly upon the constitution or configuration 

 of the starch-molecule, together with sporadic and unimportant inquiries as to the differ- 

 entiation of starches from different sources based upon differences in the products of 

 digestion, etc. 



NATURE OF THE CHEMICAL PROCESSES INVOLVED IN THE DEXTRINIZATION AND 

 SACCHARIFICATION OF THE STARCH-MOLECULE. 



From the time of the publication of the article by Musculus in 1860, in which it was 

 held that the conversion of starch into dextrin and sugar is a process of hydrolysis, it seems 

 to have been almost universally accepted that the mechanisms throughout the breaking 

 down of raw starch into its final sugars and intermediate derivatives are those of repeated 

 simple hydrolysis. This, howe\-er, is a convenient if not a justifiable assumption, as will 

 be apparent by the context. There are a number of facts which seem to be opposed to 

 it as an entirety, and which are to be harmonized before it can be accepted, as, for 

 instance, the formation of dextrin by torrefaction, certain marked differences exhibited 

 in the beha\'ior of enzymes and inorganic decomposing agents, both as regards the initial 

 substances acted upon and the final products of activity, the probable importance or 

 necessity of oxygen, as is indicated by the investigations of Sacharow (Russki Wvratsch, 

 1904, No. 17 ; Biochem. Centralbl., 1904-5, iii, 115) and Griiss (page 146) in enzymic action 

 and by Wortmann (page 186) in bacterial digestion, and the practical identity of the 

 behavior of raw starch and gelatine and other of the so-called organic colloids when placed 

 in water. 



Based upon the investigations of Musculus and Gruber, Neumeister (Lehrbuch d. 

 physiologischen Chemie, 1893, Teil i, 32) proposed the following scheme, each step being 

 one of hydrolysis: 



Starch (amidulin) -f inaltoso ^ maltose , ,. 



Whether or not there may be as many, or more or less, intermediate and final steps 

 and products is yet an open question, but in very recent years the tendency has been toward 

 the acceptance of a simpler scheme, such as the following: 



Starch-^soluble starch \ f^i?ff j^ f maltose 



\ erythrodextrm j ^p^^^jg^j^^^jj,3jjgg_^gjy^pgg 



THE PROCESSES IN THE CONVERSION OF RAW STARCH INTO STARCH-PASTE (HYDRATED STARCH), 

 AND INTO PSEUDO-SOLUTION AND TRUE SOLUTION. 



Wliile there can be no doubt of the essential part played by water in the swelling, 

 gelatinization, pseudo-solution, and solution of starch, it seems clear that none of these 

 phenomena is due either to hydrolysis (decomposition in which molecules of water are 

 taken up and become an integral part of the molecules), or hydration in the strictly chemical 

 sense (the formation of derivatives in wliich basic matter is substituted by hydrogen atoms 

 of water, or the actual combination of water so that the molecules of water constitute 

 intramolecular components of the derivatives). The terms hydrolysis and hydration are 

 often used synonymously, but at tunes incorrectly, because while hydration may mean 

 hydrolysis, it may on the other hand signify a combination with or impregnation of 

 water which is an extramolecular and not an intramolecular phenomenon. According 

 to the recent developments of physical chemistry, none of the processes concerned in the 



