JAMS. 55 



ash will be found. Still, exceptions to this rule must not be overlooked. 

 In several anah^ses of ash of apple considerable amounts of soda have 

 been shown to be present. Also, in some fruits, such as lemons and 

 oranges, the percentage of lime is much larger than is the case with 

 most other fruits. The ash of a pure fruit product, however, should 

 contain not less than 40 per cent of potash. 



By consulting the tables of analyses it will be noticed that the ash 

 of the glucose products varies exceedingly, according to the grade of 

 glucose emplo3^ed and the method of its preparation. The sulphates 

 in some cases constitute almost the entire ash, while in other cases 

 onh^ a very small part of the ash is sulphate. The average percentage 

 of ash of jams not containing glucose was 0.319, while the average 

 alkalinity was 0.262. In the compound jams the average ash was 0.590 

 per cent and the alkalinity 0.285 per cent. These proportions, how- 

 ever, will not always hold good. For example, sample No. 19887, 

 which is ver}^ largeh^ glucose, has 0.387 per cent of ash and only 

 small amounts of sulphates and chlorids. This sample evident^ con- 

 tains a better grade of glucose than that used in sample No. 19865, 

 which has 0.648 per cent of ash and 0.546 per cent of sulphates. The 

 dextrin and sugar in the sample of glucose last mentioned are present 

 in about equal proportions. An ash of this sort indicates that there 

 can be very little if an}^ fruit present. 



There is little value in a comparison of jams made from different 

 fruits by taking as a basis the amount of any constituent present, as 

 the variation is too great. The goods of one manufacturer, however, 

 may be compared with considerable value sometimes, as is seen b}^ 

 consulting Table 31, prepared to show the probability of the use of 

 a gelatinizing agent to produce a uniform product from different kinds 

 of fruits. It is well known that some fruits jelh^ readily, while others 

 do not, and with many fi'uits it is necessary to have a high content of 

 solids in order to get the required consistency. By the use of apple 

 as a basis it is possible to produce the desired consistency^ with a lower 

 percentage of solids. 



The relation between cane sugar and reducing sugar in jellies or 

 jams is of little value, as the amount of h3^drol3^sis caused by the fruit 

 acids in the process of preparation is an exceedingly variable quantity, 

 changing with the amount of boiling and the quantity and kind of 

 acid present. Data of considerable value may be obtained by a con- 

 sideration of the total sugar present and the invert polarization. The 

 following table was made by calculating all the reducing sugar as cane 

 sugar (reducing sugar x .95 = cane sugar), and adding it to the cane 

 sugar found, and from the total cane sugar, calculating the invert 

 reading at the temperature at which the polarizations of the sample 

 were made. It is easily seen that if the fruit product had contained 

 no sugar besides the sugar of the fruit and pure cano sugar the ob- 

 served polarization and the calculated polarization would be very close 



