98 TROPICAL AGRICULTURE 



the stump and the fruit stem are completely filled with starch. 

 The supply of sugar for the ripening pineapple is, therefore, 

 secured from the starch in the stump by transformation and 

 translocation. It is obvious, therefore, that when the fully 

 grown pineapple, still green and firm, is cut from the plant there 

 is no material in the fruit which can be transformed into sugar 

 during the process of ripening. Fruit picked in this condition, 

 however, does undergo a process of ripening. The normal 

 color of the ripened fruit develops and the tissue of the fruit 

 becomes soft and juicy. Fruit picked in a green condition, 

 however, contains no more sugar when it is fully ripe than at 

 the time when it was taken from the plant. In the condition 

 in which pineapples are commonly picked for shipment as fresh 

 fruit, the pineapple fruit contains about 4 per cent, of sugar. 

 In the fully ripe condition, on the other hand, the pineapple 

 contains from 9 to 14 per cent, sugar with an average sugar 

 content of about n per cent. It is sufficiently obvious, without 

 argument, that the flavor of a fruit containing n per cent, of 

 sugar is far superior to that of one containing only 4 per cent. 

 Pineapples are not harvested for canning until they are com- 

 pletely ripe and are then canned within 24 to 48 hours after 

 being harvested. For this reason the flavor of ordinary canned 

 pineapples is superior to that of the average run of fresh pine- 

 apples to be found on the market. Without refrigeration it is 

 impossible to ship perfectly ripe pineapples for the reason that 

 they are too easily bruised and immediately begin to ferment. 

 The difficulty of placing fresh pineapples in their best con- 

 dition on the northern markets was not to be overcome with- 

 out the use of refrigeration. A study was, therefore, made by 

 the Hawaii Experiment Station to determine whether refrig- 

 eration was adapted for use for pineapples. These experiments 

 were begun after the Hawaii Station had worked out the essen- 

 tial chemical processes in the ripening of the pineapple fruit. 

 Pineapples were placed in cold storage rooms at temperatures 

 of 32 and 36 F. The fruit used in these experiments was in 



