COMPOSITION OF THE CHINESE JUJUBE. 
By C. G. Church, Assistant Chemist, Laboratory of Fruit and Vegetable 
Chemistry, Bureau of Chemistry. 
In view of the interest aroused by the successful propagation and 
distribution of the Chinese jujube by the Bureau of Plant Industry, 
it seemed desirable that a study of the general composition of this 
fruit be undertaken. No such data concerning fruit grown in the 
United States appeared to be available. 
For this purpose samples of fruit at different stages of maturity 
were supplied by the United States Plant Introduction Garden at 
Chico, Calif., and the results of the analysis of these samples are 
tabulated and discussed in the following pages. 
SAMPLES EXAMINED. 
The samples usually reached the laboratory two or three days after 
being picked. In some cases it was impossible to handle them as 
soon as they were received, and such samples were held in cool storage 
(4° C.) until they were analyzed, the time varying from one to nine 
days. The effect of storage at this temperature upon the composition 
of the fruit is difficult to estimate, but there seems to be no great loss 
of sucrose under these conditions. It is possible that enzymic 
activity continues and changes the proportions of the different 
sugars, but it is doubtful whether the total sugars are affected or 
any of the other constituents undergo appreciable change. 
METHODS OF ANALYSIS. 
The methods of analysis used were those prescribed by the Asso- 
ciation of Official Agricultural Chemists 4 for foods and feeding 
stuffs, with one or two variations, as follows : 
Moisture. — Official method, drying at 70° C. in vacuo. Quartz sand was 
omitted, as the residue was used for crude-fiber determinations. 
Sugars. — The sample was extracted with hot water, to which had been added 
a few drops of concentrated ammonia to neutralize the acidity and prevent 
inversion of the sucrose. After the usual clarifications, the cuprous oxid was 
precipitated, according to the Munson and Walker method, and subsequently 
determined by the official volumetric permanganate method. 
Acidity. — The sample was boiled for 30 minutes in 200 c. c. of distilled water 
and allowed to stand over night. The resulting extract was titrated against 
standard alkali, phenolphthalein being used as an indicator. 
Protein. — Nitrogen was determined by the official Gunning method and the 
result was multiplied by 6.25. 
Ether extract. — Official direct method. 
Crude fiber. — Official method. 
Ash. — Official method. 
Pectin!" — The determination was made by the usual double alcoholic precipi- 
tation method. 
« Association of Official Agricultural Chemista Official tentative meUiods of anal- 
ysis, as compiled by the Committee on Revision of Methods. Revised to November 1, 
1919. 417 p., 18 fig. Washington, D. C. 1920. 
6 II. D. Poore made the pectin determinations. 
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