TRANSACTIONS OF WAGNER 

 94 



THE CHEMISTRY OF BREAD-MAKING 



diminution of the water (drying out) and the retention of part of the water in 

 the peculiar form spoken of under water as a constituent of bread. 



Sometimes changes of an abnormal character occur, usually of biologic 

 origin, caused by molds, bacteria, etc., as noticed in ordinarily moldy bread 

 in which the common mold gives a green color superficially. A red bread is 

 sometimes seen, caused by a less common microbe. This being of a bright 

 color resembling blood, is startling when seen for the first time, even by an 

 educated person who knows how to account for it. Among the ignorant it 

 usually causes unwarranted fears, hard to allay. Ropy bread is another con- 

 dition of abnormahty brought about by bacterial action. In such bread, 

 when pulled apart, the crumb, instead of breaking off more or less short, 

 stretches out into long elastic strings. These conditions are all accompanied 

 by chemical changes, imperfectly understood, and not capable of definite 

 description. 



In wrapped bread, now coming into more wide-spread use in response to 

 the modern demand for more careful sanitary handling of foods, there are also 

 some more or less obscure changes hkely to occur, especially if it is wrapped in 

 absolutely impervious paper, which has come to be recognized as not so good 

 as one which is slightly porous. Moldiness and souring have been reported. 

 Increase in the amount of aqueous extract, partial hydrolysis of starch, in- 

 crease in amount of soluble proteins, and increase in acidity have all been re- 

 ported. These changes are all undoubtedly due to the action of molds or 

 bacteria. They are being studied constantly, and as our knowledge increases 

 these changes are being minimized by knowing just the length of time the 

 bread must stand before being wrapped as well as the proper kind of paper 

 to use in wrapping. If, however, these precautions are observed, wrapped 

 bread is just as good and wholesome as unwrapped bread. 



The foregoing chemical changes are those normally occurring in bread- 

 making. It is proper, in closing, to refer to some of the adulterants of bread 

 and the chemical changes, if any, resulting from their use. Such adulterants 

 as talc, terra alba, clays, etc., which have been reported in former times, are 

 purely mechanical and play no part in the chemistry of the subject. Their 

 presence has not been reported for many years, and they are of little or no im- 

 portance at present. 



Potassium alum has been used surreptitiously during several hundred 

 years for ostensibly improving the bread, but is now forbidden by the food 



