Chestnut Tannins Research Articles

Effects of vegetable tannins on glucose oxidation by various microorganisms.

The effects of purified tannin preparations of chestnut wood and of wattle bark on the respiration of resting cells of microorganisms were measured in a Warburg apparatus. Tannins were tested at 0.5% (w/v) concentration alone and in mixtures with glucose which provided energy for the microorganisms. In presence of the chestnut and wattle tannins, the exogenous respiration of Asotobacter vinelandii was reduced by 50 and 85% and that of Escherichia coli by 40 and 20%, respectively; respiration of Azatobacler chroococcum was completely inhibited by either tannin. Glucose oxidation by Rhizobium melioti, Rhisobium sp., and Saccharomyces cerevisiae was inhibited by tannins to small degrees. Tannins had no effect on glucose utilization by Rhodotorula sp. and Pseudomonas fluorescens. A. vinelandii, E. coli, and P. fluorescens utilized tannins, especially wattle, as an energy source.

A method for separating the constituents of chestnut tannin

AbstractIn the course of work in this laboratory it was desired to separate the constituents of a comercmial sample of chestnut tannin. A method of effecting at least a partial separation is described; it appears that this may be more generally useful in tannin fractionations as it is also applicable to oak and quebracho tannins.When an aqueous solution of chestnut tannin is passed through an absorbing column of wood cellulose powder (Solka Floc), and the column is subsequently developed with a 4% solution of sodium chloride, at least six different bands show up; the fractions represented by these bands have been collected and show different properties. The fractions are not pure, but refractionation of one of the major bands demonstrates that further purification is easily achieved.