Dec. 15. 1914 Changes in Composition of Ripening Bananas 



201 



We are therefore justified in calculating the water formed by the equa- 

 tion C8Hj20j + 6O2 = 6CO2 + 6H2O. From the water so formed is sub- 

 tracted the water absorbed in the saccharification of starch. See Table 

 VIII. 



Table VIII. — Percentage of water formed by the pulp of bananas in physiological 



processes 



a Probably slightly larger than actual on account of failure to completely estimate maltose. See p. 189. 



In the first two experiments absorption of water amounting to 0.782 

 and 0.512 per cent occurred as a net result of respiration and starch 

 hydrolysis. In the fourth experiment, where the bananas became over- 

 ripe, the water formed in respiration was greater by 0.195 P^r c^'nt than 

 that absorbed in starch hydrolysis. 



The increases of water in the pulp during ripening are all derived from 

 the peel, except when bananas become overripe, when the water formed 

 in respiration may more than balance the water absorbed in starch 

 hydrolysis. From the quantity of sugar formed in the pulp it is evident 

 that the osmotic pressure of the pulp must undergo a marked increase, 

 with a corresponding decrease of vapor pressure, during the ripening of 

 the fruit. A possible operating cause of the water transfer from peel to 

 pulp is obvious. 



From a knowledge of the carbon dioxid formed in respiration and know- 

 ing from the calorimeter data that carbon dioxid results from the com- 

 plete combustion of carbohydrates, it can be determined whether or not 

 the carbohydrates consumed in respiration were accurately made known 

 from the analyses. Carbohydrate losses found by analysis contrasted 

 wath the expected losses from the calorimeter data are shown in Table IX. 



Table IX. — Comparison of carbohydrate losses with theexpected losses from carbon dioxid 



in pulp of ripening bananas 



