38 CHEMICAL COMPOSITION OF SOME TROPICAL FRUITS. 



Table XIII contains the results of analysis of 43 samples of canned 

 pineapples from Singapore, the Straits Settlements, and the Bahamas. 

 It is apparent from the high content of sugars that practically all of 

 the canned pineapples from Singapore and the Straits Settlements are 

 preserved with addition of cane sugar. On the other hand, the 

 analyses indicate that but few of the samples from the Bahamas have 

 had any addition of cane sugar. 



A study of the data contained in the foregoing tables fails to bear 

 out the common supposition that the pineapples grown upon or near 

 the equator contain more sugar than those grown at some distance 

 farther north, and, in fact, the normal content of sugar in pineapples 

 grown in Florida differs so little from that of pineapples grown at 

 Singapore that the difference is practically negligible. 



It may not be out of place to state at this point that these investiga- 

 tions were undertaken in the Bureau of Chemistry at the request of 

 the Secretary of the Treasury for the purpose of establishing a basis 

 of classification for imported pineapples for the guidance of the 

 appraisers. Since the classification of these bodies for dutiable pur- 

 poses depends upon the answer to the question of whether or not 

 sugar has been added during the process of preserving, it was neces- 

 sary first to establish the normal content of sugar in the pineapples. 

 It is evident, from inspection of the analyses, that since the normal 

 pineapples contain a large quantity of cane sugar, the mere presence 

 of this substance would be no evidence whatever of its artificial addi- 

 tion. It is further evident that if a sirup containing practically the 

 same quantity of sugar as the natural sirup of the pineapple were 

 added it would be quite impossible, by a mere determination of the 

 sugar present, to detect the addition. The only guide in this case 

 would be to determine the Kelation of the sugar present to the total 

 insoluble matters of the pineapple. If, on the other hand, a sirup 

 rich in sugar were added in preserving, it would be easily detected by 

 the increase 1 in the percentage of sugar in the contents of the can. 



In looking over the accessible literature relating to the analysis of 

 pineapples, at the commencement of these investigations, it was sur- 

 prising to find that no paper has been published on this subject except 

 one by Buignet in "Les Sucres," published byMaquenne (Paris, L900). 

 The average content of sugar found by Buignet, viz. 1H.<* per cent as 

 invert sugar, is not materially different from the amount found in these 

 investigations. 



