576 Howard : Tannin cells of persimmons 



Experiment also demonstrated that fruit packed in a container 

 with vapors of chloroform lost its astringency much quicker than 

 those simply kept in a container without the chloroform, but there 

 was developed at the same time a marked increase in the degree of 



mushiness. 



Another feature which is commonly associated in our minds 

 with the ripening of persimmons, is the development of mushiness. 

 This feature, however, does not run parallel, stage for stage, with 

 changes in the tannin, for it not infrequently occurs that mushi- 

 ness develops before the astringency is gone, while in other cases 

 just the reverse is true. The latter case is notably so in specimens 

 artificially cured by the saki process. In this method, which is 

 largely employed by the Japanese in ripening their varieties, the 

 fruit is stored for a few days in empty saki barrels. At the end of 

 the treatment it is found that the tannin has all been localized and 

 rendered insoluble in water, though the flesh of the fruit is nearly 

 as firm as that of an ordinary apple. From this it seems that the 



* 



change in the physical characteristics of the tannin is not at all 

 closely related to the development of mushiness. This makes 

 highly improbable a hypothesis, which we at first thought might 

 be true, namely, that as the middle lamella was rendered soluble 

 in the process of ripening it in some way combined with the tannin, 

 producing a compound insoluble in water. Mr. Gore, of these 

 laboratories, in his studies into the chemical changes occurring 

 during the process of ripening of persimmons, has demonstrated 

 that the sum of tannin and marc (pulp less alcohol-soluble matter) 

 is nearly a constant throughout the process of ripening; from 

 which it seems improbable that the tannin combines with any 

 soluble substance, such as sugar, producing an insoluble com- 



• !• 



as 



process maintains its power of color reaction toward tannin re- 

 agents such as iron salts and chromic compounds. 



Bureau of Chemistry, 



United States Department of Agriculture 



