Dec. 15, 1914 Changes in Composition of Ripening Bananas 191 



SECOND EXPERIMENT 



In the second experiment similar composition changes occurred. In 

 addition, it was demonstrated that the banana stem does not contribute 

 materially to the fruit during ripening. The details of this experiment 

 are as follows: 



Four bunches of green bananas, consisting of the most evenly ripened 

 fruit, judging by color, of a lot of eight bunches of the green fruit, were 

 placed in the calorimeter after sampling and weighing. Six fruits had 

 been removed as samples from each of two bunches of green bananas 

 and eight from each of the others. 



During ripening the temperature varied from 20.9° to 24.2° C, averag- 

 ing 23.1° C; the oxygen content of the air varied between 20.0 and 6.1 

 per cent by volume, averaging 14. i per cent; and the humidity remained 

 high, as before. When removed, all of the fruits were thoroughly ripe, 

 and indeed one bunch was slightly overripe. Several specimens on this 

 bunch were beginning to spoil. The skins were bright golden yellow, 

 and the fruit surfaces were waxy and moist. No browning occurred, 

 except where the bananas were superficially injured. 



After weighing, the bunches were again sampled. In the analyses 

 determinations of protein, ash, and ether extract were omitted, as the 

 quantities of these substances present had been found to change but 

 very slightly during ripening. 



The four bunches remaining after selection of the bananas for the 

 respiration calorimeter were used in the study of the composition of 

 the green stem. Mr. W. H. Evans, of the Office of Experiment Stations, 

 suggested that possibly the stem contained reserve materials supplied 

 to the fruit during ripening. The bananas were detached from the 

 stems in the same manner as when taking samples for analysis, leaving 

 on the stems the stubs of the short stems by which the bananas were 

 attached. The percentage of stems was 5.04 per cent. They were 

 finely divided in a shredding machine and analyzed, using the methods 

 employed for the analysis of peel and pulp. At the conclusion of the 

 ripening experiment in the calorimeter the weight of the stems of the 

 ripened bananas was determined and the stems then ground and analyzed. 



The original weight of the four bunches of green bananas placed in 

 the calorimeter after sampling was 75.90 kg. They suffered a loss upon 

 ripening of 6.36 kg., or 8.38 per cent. 



The bananas after ripening consisted of 95.30 per cent of fruit and 

 4.70 per cent of stem. Assuming that the fruit and stalks lost weight 

 in equal proportions, the respective weights of green fruits and stems 

 when placed in the calorimeter were 72.33 and 3.57 kg. The propor- 

 tions of pulp and peel of the green bananas were 58.22 and 41.78 per 

 cent, respectively. The entire bunches of green bananas as placed in 

 the calorimeter after sampling consisted therefore of 55.48 per cent of 



