488 Journal of Agricultural Research voi. xix, No. 10 



temperature from 65° to 70° F., curves 5 and 6 in 40° storage, and 

 curves 7 and 8 in 30° storage. The distance between these curv^es and 

 curves i and 2, at the various dates, represents the increase in sugar as 

 the fruit ripened in the dififerent storages. It will be noted that the 

 sugar runs uniformly highest in the fruit ripened at 70°. This is true 

 for both total and reducing sugar in fruit picked at all the different dates. 

 Apparently, either the loss of sugar from respiration is less, or more sub- 

 stances insoluble or nonreducing in the green fruit are changed to soluble 

 reducing material when the fruit is ripened at this optimum ripening 

 temperature than when ripened at lower temperatures. 



In every lot, regardless of the section from which it came or the date 

 at which it was picked, fruit held at 30° F. was higher in sugar than that 

 stored until ripe at 40°. It must be borne in mind, however, that the 

 30° fruit was not completely ripened in storage but was held for periods 

 of from a little over three months in the early picked lots to a little over 

 six weeks for the last lots from Oregon and Washington. Then it was 

 removed and held at warm room temperature until ripe, the time required 

 being four to six days. This may have made some difference in the 

 analytical results. Also, at one period, because of a sudden drop in 

 temperature, the fruit picked in the earlier lots was partly frozen. It 

 was thawed very gradually, and no ill effects of the freezing were notice- 

 able afterwards. The fact that the frozen lots and those of the later 

 pickings that did not freeze showed no marked difference in analyses 

 other than that to be expected from the results with the same lots in 

 other storages is also evidence that the carbohydrates of the fruit were 

 not materially affected by the freezing. 



The general effect of storage upon the sugar content of the fruit was 

 very similar, however, in fruit from the different sections. The curves 

 for total sugar — No. 2, 4, 6, and 7 — cross in only one point in all the 

 figures, showing that the relative amounts of sugar in the different 

 storages run the same in all cases. It seems well estabhshed, there- 

 fore, that the highest amount of sugar will be secured by holding the 

 fruit at optimum temperature for ripening. In case it is necessary to 

 prolong the time of keeping the fruit, holding it at very low temperature 

 until near the time it is needed and then ripening it up at optimum tem- 

 perature gives a higher sugar content than holding it at a temperature 

 just low enough to retard the ripening processes. From the results 

 obtained by Gore (5) on the respiration activity of fruits at different 

 temperatures, it would be expected that respiration would occur at 

 least three times as rapidly in the 70° as in the 40° F. The number 

 of days required to ripen the fruit in the two storages was about in the 

 proportion of three days at 40° to one at 70°, so the total respiration 

 activity would seem to be about equal. If this is true, it would seem 

 that certain factors other than respiration must enter into the relative 

 amounts of sugar present in the different storage lots. 



