あおみどろタンニンの研究

(其の3)あおみどろのタンニン含量に就て

抄録

The tannin content of naturally living Spyrogyra arcta has been estimated. The method is as follows: Freshly prepared sample is extracted with 70% acetone by using the SOXHLET's apparat (Table 2). After the removing of acetone on boilling water bath, the residue is filled up to 100cc with water and tannin content is estimated by the method of the colloidal titration method. After 5cc of N/200 N=methyl polyglycol glucosamine and 5cc of 1N NH⁴OH are added to 10cc of tannin solution, this mixed solution is titrated with N/400 potassium polyvinyl alcohol sulfonate (Fig. 1, Table 1 and 3).
The relationship pf the tannin content of Spyrogyra arcta to several conditions is shown in Table 4 and Fig. 2. The tannin content is about 3.5_??_5%.