ACIDITY IN DETERMINING SOUNDNESS OF CORN. 



37 



G R /=l D £ 



N°3 



N°4 



T£ 



made consisting of 90 per cent of this sound corn and 10 per 

 cent of the damaged corn showing an acidity of 45 c. c, the sample so 

 prepared would show theoretically a degree of acidity of 22.05 (90 

 per cent of 19.5 c. c. plus 10 per cent of 45 c. c). This sample would 

 be stamped as being "unsound corn" according to the acid test. The 

 percentage of damaged kernels may vary considerably in corn 

 regarded as sound by 

 the acid test. This is 

 dependent upon the 

 degree of soundness or 

 quality of the kernels 

 judged by the eye as 

 being not damaged. 



As a result of this 

 investigation, 22 c. c. 

 is recommended as ap- 

 proximately express- 

 ing the maximum de- 

 gree of acidity found 

 to be contained in corn 

 considered commer- 

 cially sound. Corn 

 showing a degree of 

 acidity exceeding 22 

 c. c. indicates the de- 

 velopment of excessive 

 acidity through the de- 

 terioration of the germ, 

 and is discriminated 

 against as being of 

 poorer quality than 

 corn showing a degree 

 of acidity less than 

 22 c. c. 



In the determination 

 of soundness and qual- 

 ity of corn by means of 

 the acid test, it is the 

 large bulk of the corn 

 which must bo consid- 

 ered rather than the 10 or 15 per cent of damaged kernels which the 

 sample under analysis may contain. The acid test measures defi- 

 nitely the quality and soundness of the 85 or 90 per cent of the so- 

 called "sound kernels," as recognized by the analyst or inspector in 

 his determination of 10 or 15 per cent of damaged kernels by means 



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Fig. 28.— Curves showing the increase in the degree of acidity of 

 samples of corn from the high to the low grades where there is also 

 a corresponding increase in percentage of damaged kernels and 

 decrease in percentage of germination, as found to represent ap- 

 proximately 900 cars of corn received at a principal terminal 

 market (C) throughout a year, all of which corn contained less 

 than 16 per cent of moisture and was graded according to quality 

 and amount of damage. 



