REPORT OF CRANBERRY SUBSTATION FOR 1916. 237 



Effect of Carbon Dioxide on Cranberries. 



Several series of tests were made in which cranberries from various 

 sources (Early Blacks and Howes from Massachusetts, and Howes from 

 New Jersey) were kept for short periods in an atmosphere of nearly pure 

 carbon dioxide. It was noticed in each case that at the end of three days 

 practically a]] the berries in the carbon dioxide were spoiled, whereas ber- 

 ries from the same lots kept in similar containers with air showed very 

 little rot even at the end of two weeks. 



The berries which had been kept in an atmosphere of carbon dioxide 

 had the peculiar uniform duU, lusterless, red color which had been noticed 

 in many of the berries which had spoiled in closed cans. On sectioning 

 these berries it was found that the tissue of the berry, which is white in a 

 normal berry, had taken on the same uniform red color. Berries which 

 have been treated in this manner have a peculiar, bitter taste, which is very 

 characteristic. They are no longer firm, as in the sound fruit, nor elastic 

 to the touch as in rotten fruit, but have become flaccid. The same effect 

 on the berries was readily produced by sealing up a quantity in an air- 

 tight container, and allowing them to remain at room temperature for a 

 week. 



That this injurious effect is produced by the accumulation of carbon 

 dioxide is indicated by preliminary tests made in December, 1916. Equal 

 quantities of sound Early Blacks or Howes were put in similar containers 

 (Hempel desiccators). One of these desiccators was filled with carbon 

 dioxide, the other two contained air, but the upper portion of one of them 

 was filled with a saturated solution of potassium hydroxide, which would 

 absorb the carbon dioxide almost as fast as given off by the berries. The 

 berries in the fii'st lot were thus exposed to an atmosphere of carbon 

 dioxide throughout the test; those in the second lot were exposed to air 

 containing practically no carbon dioxide; and those in the third to an at- 

 mosphere in which the carbon dioxide given off in respiration was allowed 

 to accumulate. The results of one of these tests which was typical of all 

 are given in the following table : — 



It will be noted that the amount of spoilage, including rot due to fungi, 

 is greatest in the berries exposed to carbon dioxide and least in the con- 

 tainer from which this gas was removed, which apparently indicates that a 

 large portion of the spoilage was due to the carbon dioxide. 



