72 



Jour. Soc.Chem. Inch, 1417 Arpin (abs.) (1902) ; 368, Baker & Ilulton (1908). 



Canadian Dept. Agric, [57], 37, Shutt (1907). 



Jour. Board Agric. Supp. 4, 29, Saunders (1910); o2, Hardy (1910). 



Agric. Gaz., N.S. Wales, Guthrie (1896). 



Compt. Rend., 123, 755, Fleurent (1896); 132, 1421, Fleurent (1901). 



Agric. Expt. Stn., Arkansas, Bull 53, Teller (1898). 



U.S. Dept. Agric., Bull 101, 66, Snyder (1901). 



Zeit. anal. Chem., 44, 516, Osborne & Harris (1903). 



Jour. Agric. Soc, 2, 1, Humphries & Biffen (1907). 



(c) Mineral Salts. 



The character of bread and, incidentally, the character of gluten 

 are so intimately connected with the action of mineral salts (or other 

 electrolytes) upon colloids, that reference should first be made to the 

 collection of information to be fourwd in the two jirevious Reports. 

 The works of Wood and Hardy have already been referred to, and 

 scattered through the Uterature on colloids may be found many other 

 references to the influence of various salts upon wheat gluten, the 

 chemical composition and original nature of which is seldom specified. 



The " maturing of gluten " is often mentioned in technical works, 

 and means little else than modifying a " short " gluten to a condition 

 by which it is capable of retaining the gas generated by the yeast. 

 Kohman and Hoffman {Jour. Ind. Eng. Chem., 1916, 8, 781-9; 

 1917, 9, 148-59) have made special claims for potassium bromate 

 in this connection, and have employed it in a special yeast food which 

 was used in the U.S.A. Army with great success. It should be noticed 

 that the action of potassium bromate is more effective the higher 

 the grade of flour used, both in modifjong the gluten and in improving 

 the colour and texture of the bread {R»p. Conn. Agric. Expt. Stn., 

 Bull, 200, 1917). The addition of alum was but another attempt 

 to modify a bad gluten, the hardening or coagulating effect of that 

 chemical upon many colloids being well known (Odling, Jour. Soc. 

 Arts, 1858). As a rule, alum was only employed on cAd or damp 

 flour, in which the gluten had deteriorated due to the action of acetic 

 or lactic acids. [See also the ancient use of sulphate of cojiper for 

 improving flour. (Liebig, " Letters on Chemistry ").] 



Deterioration wdth age of the physical qualities of gluten for 

 bread-making is also well loiown (Whymper, R., " Knowledge," 

 36, 85, 1913), whilst the maturing effect on flour gluten of time and 

 bleaching materials should be considered. (i?e^3. Local Govt. Board, 

 1911, I. and II., N.S. 49, Food Report 12, by Hamill and Monier- 

 Willianis respectively.) 



The nature of the Abater used in bread-making is of as much 

 importance in securing quality as in brewing. It is, of course, the 

 quality of the contained mineral salts in the water that determines 

 the suitability or otherwise of any given source. The action of the 

 salts is not only upon the starch and gluten colloid systems but also 

 upon the degree and speed of development of yeast cells. The effect 

 of soft and hard waters upon gluten has already been mentioned ; 

 that upon yeast nd fermentation can be found in any text-book 

 (Reynolds Green, " The Soluble Ferments and Fermentation," d:c.). 

 It is not without interest in the latter connection that Miiller 



