ON KAKI-SHIBU, A FRUIT JUICE IN JAPAN. 



331 



tannin ; but this has some abnormal properties, as will be seen 

 later on. 



When water is mixed slowly with old Kaki-shibu it can be 

 observed that the latter remains for sometime suspended in the 

 water in the form of a reddish and slimy liquid and only on 

 shaking' well does a complete distribution result, but this solution 

 remains opalescent. Fresh Kaki-shibu is whitish and nearly 

 odourless ;" old Kaki-shibu is more or less reddish brown, and 

 gives off the odour of butyric acid. Old commercial Kaki-shibu 

 in the undiluted state will yield when exactly neutralized with 

 sodium carbonate a fiocculent precipitate, and soon afterwards a 

 jelly which is almost insoluble in boiling water and alcohol. 

 Boiling alcohol does not extract a tannin-like compound while 

 the insoluble part turns black at once in contact with ferric 

 chloride, which shows that the tannin compound has here 

 exceptional properties. The jelly mentioned is, however, 

 soluble in dilute acids, but it is again precipitated by the 

 addition of an excess of strong acids, as whitish flocculcs. The 

 acid solution also gives precipitates by ferric chloride and basic 

 lead acetate, but not by phosphotungstic acid. The jelly is 

 soluble in dilute sodium carbonate, which latter solution becomes 

 very dark on contact with the air. 



The fresh juice shows only a moderate acid reaction but this 

 reaction increases on standing, 1 which is no doubt due to the 

 moderate development of microbes. On distillation in a current 

 of steam a considerable portion of the acid distills over.- I have 

 determined by titration the total acidity, and further the amount 

 of non-volatile acid after evaporation of IO c.c. to dryness. It was 

 thus found that the amount of volatile acid is almost equal to 

 that of the non-volatile acid in new Kaki-shibu, while it is more 

 than twice as great as the amount of non-volatile acid in the old 

 Shibu. :: 



1 For my observation for the acidity served two kinds of Kaki-shibu prepared in the 

 same place, one of which was made this year (1901) and the other last year. The total 

 acidity per litre of the new and of the old corresponded respectively to 0.978 g. and 

 1.948 g. of S0 3 . 



- The nature of this volatile acid was investigated about twenty years ago by Prof. 

 I. Ishikawa (1. c. p. 19-20) who found butyric acid in it. 



a The samples that served for my analysis came from Awotani-mura, Tsuzuki 

 county near Kyoto. The new Kaki-shibu was prepared this year (1901), and the old 

 in the last year (1900). 



