A new method based on coulometric titration with potentiometric indication of the titration end point has been developed for the determination of the organic-acid content in wild-rose fruit, cholosas preparation, and wild-rose syrup. The relative error of the coulometric determination of organic acids does not exceed 2%.

A model of extracting the natural products through boiling ground plant material in a solvent using a bain marie is proposed. The model trait is that it has only one adaptation parameter, i.e., the diffusion coef ficient of the solute in the plant material, which depends on the solvent and plant material properties. The model is applied to study the kinetics of extraction, and the minimal solvent volume, which is used for extrac tion, is theoretically determined. A comparison of the model with the experimental data of the extraction of hydrophobic diterpene acids from sage leaves and hydrophilic flavonoids from common knotgrass herb is in good agreement with the experiment. Experiments performed with finely ground plant material (particle diameter is less than 1 mm) show that, for most extraction conditions, more than 90% of the target com pounds are extracted by the time the solvent starts to boil.

No abstract

No abstract