July 13, 1919 Carbohydrate Metabolism in Green Sweet Corn 149 



com used in this work. According to the foregoing rate of respiration 

 this system would lose 163.72 mgm. of sugar during the first period of 

 storage of 24 hours. At the same time 98.269 mgm. of water would be 

 freed in the system. Our system would now contain 80.0983 gm. of 

 water and 4.8363 gm. of sugar. By correcting for the slight loss of dry 

 matter, the system would contain 80.1507 per cent water and 4.8395 

 per cent sugar. These percentages would be those found by actual 

 analysis of the 100 gm. of corn after 24 hours' storage, assuming that no 

 other changes occurred besides respiration. 



If we now calculate the percentage of sugar on the basis of the original 

 water in the system, as was done in all cases in this work, the percentage 

 of sugar would be 4.8726, showing a loss by respiration of 0.1274 per cent. 



It should be noted that the rate of respiration chosen for this illustra- 

 tion was the rate for the highest period at 30° C. It was also assumed 

 that all of the carbon dioxid came from the kernels. During the imma- 

 ture stages of the com it is very probable that some of the sugar in the 

 cob is consumed by respiration. 



During the later periods at the high temperatures and for all periods 

 at the low tempeVatures, the change in the percentage of sugar by res- 

 piration during the short periods of 24 hours would be practically within 

 the experimental error for the sugar and moisture determinations. 



One ton of husked green sweet com, during the first 24 hours of stor- 

 age at 30° C. would lose approximately 3.2 pounds of sugar on account 

 of respiration. 



Under certain conditions, however, respiration may become an impor- 

 tant factor in accelerating the depletion of sugar from green sweet com. 

 One of the products of respiration is heat. This heat of respiration will 

 raise the temperature on the inside of large piles of green corn to a very 

 marked degree. The increased temperature accelerates not only the 

 respiratory process itself but also the other processes responsible for 

 most of the sugar loss. Aeration of green corn is therefore important in 

 order to dissipate the heat of respiration. In other words, green corn 

 should not be allowed to remain in large piles for even a short time, 

 especially during midsummer temperature. 



Starch formation. — If the sugar is all converted into starch or other 

 polysaccharides, hydrolyzed by dilute acids, then the sum of the total 

 sugars and the polysaccharides as glucose should be the same before and 

 after storage. During the first period there is a slight deficit after 

 storage, especially in the more immature ears. A part of this deficit is 

 due to the high respiration of this period; but some of it is probably 

 accounted for, in the immature ears when the sugar is high, by the for- 

 mation of cellulose. During the later periods of storage many of the 

 ears, depending largely upon the stage of maturity, show a slight increase 

 in the sum of the total sugars and polysaccharides. This is true espe- 

 cially at the higher temperatures and is probably accounted for by the 



