NOTES ON THE CHEMICAL NATURE OF THE 



"TANNIN MASSES" IN THE FRUIT OF 



THE PERSIMMON 



ERNEST D. CLARK 



(Biochemical Laboratory of Columbia University, at the College of Physicians 



and Surgeons, New York) 



Introduction. The researches of Lloyd upon the nature of the 

 ripening process in persimmons and dates led him to believe that the 

 loss of astringency at maturity is due to the combinatlon of tannin 

 with a colloidal substance of carbohydrate nature in the "tannin 

 mass." This combination takes place ordinarily at the time of 

 ripening, probably under the influence of enzymes ; but it may be 

 hastened by artificial means, such as exposure to the vapors of acetic 

 acid and ethyl nitrite, and to carbon dioxid under normal and supra- 

 normal pressures. Lloyd^ defines his tannin mass as "the tannin 

 idioblast containing tannin associated with a second coUoid." After 

 the Union of tannin and this colloidal substance has taken place no 

 more tannin can be extracted nor do alkaloids indicate its presence. 

 It is evident, then, that a knowledge of the chemical substances in the 

 tannin mass would facilitate further investigation of the mechanism 

 of the ripening process. 



Preparation of tannin masses. The tannin masses used in 

 cur experiments were prepared by Prof. F. E. Lloyd^ as follows : 

 Fully ripe persimmons (Diospyros) were shaken and macerated 

 with water until they formed a thick paste, from which the heavy 

 tannin masses settled out. This process was repeated until the sepa- 

 rated masses were thoroughly washed by decantation and also 

 purified from all debris. The resulting thick Suspension of tannin 



''Lloyd: Biochemical Bulletin, 1911, i, p. 7. See also Plant World, 191 1, 

 xiv, p. i. 



^ Lloyd: Zeitsch. f. Chem. und Ind. d. Kolloide, 1911, ix, pp. 65-73. The 

 material was shipped to this laboratory from Prof. Lloyd's laboratory at 

 Auburn, Ala. 



412 



