310 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



degree. The unfrozen lemons held in storage averaged 1 gram of 

 sugar per fruit, while those that were frozen decreased from .7 to .2 

 gram per fruit. The fruit which remained on the tree showed about 

 the same amount of variation. 



The tables for invert sugar and sucrose present data that is little 

 different from those in the total sugar (see tables 10 and 11). In 

 other words, there seems to be practically no change in the relative 

 amounts of the different classes of sugar present. 



ACID CONTENTS 



The percentage of acid in the frozen and unfrozen oranges in 

 storage decreased in almost the same degree. The fruit picked at 

 different intervals showed the same change in acidity as the fruit in 

 storage, but had a lower average. Owing to the fact that lemons 

 have a much higher percentage of acid than do the oranges, a much 

 greater variation is found between the unfrozen and frozen fruit. 

 The unfrozen lemons kept in storage averaged 6.98 per cent acid 

 throughout the experiment, while the frozen ones averaged 5.19 per 

 cent. The acid in the fruit picked at different intervals averaged 

 6.27 per cent in unfrozen lemons and 4.79 per cent in frozen samples 

 (see table 12). 



r FE TABLE 12. Per Cent Acid in Juice* 



Date 

 1/14 



18 



22 



26 



30 

 2/ 7 



15 



23 



3/ 3 



7 



11 



15 

 Average 



(a) Fruit picked on January 13th. 



(b) Successive new lots picked on date given. 



* The acid was determined by titration, usins; phenolphthalein as an indicator and was calculated to 

 anhydrous citric acid. 



We find again, however, that, as with sugar, the total amount 

 of acid present decreases very markedly in the frozen fruit. The 



