No abstract

It has been established that the influence of surface-active agents (SAAs) on the extraction of essential oils (EOs ) is connected with a fall in the surface tension of water, which facilitates the process of steeping, wetting, and swelling of plant raw material and also the solubilization of the EOs in micellar solutions of SAAs.The main method of isolating essential oils (EOs) from plant raw materials is steam distillation. In view of this, it is necessary to develop scientific principles of regulation of the processes at the phase-separation boundaries of dispersions of medicinal plants and solvents. Nontraditional methods based on the use of liquefied gases [1, 2], wide-range frequency vibrations, electric and magnetic fields, impulses, etc. [3, 4] are being used to solve this problem. In the present paper we give results on the possibility regulating the properties of the surface of a dispersion of plant origin and the structure of a solvent (water) with the aid of additions of surface-active agents (SAAs) in order to intensify the extraction of EOs. where AX is the displacement of the meniscus in a calibrated capillary; D is the diameter of the calibrated capillary (1.18--2.28 ram); D o = 37 mm is the diameter of the tube into which the sample powder was charged; and n is the porosity of the raw material.It can be seen that with a rise in the concentration of the SAA the depth of penetration of the raw material increased.A. Sultanov

An increase in the yield of rutin from the extraction of Japanese pagoda tree buds on the use of surfaceactive agents because of a facilitation of the wetting process and an acceleration of the swelling of the raw material has been demonstrated.Many publications have been devoted to methods of extraction [1, 2]. It is known that the initial stages of the process of extracting medicinal plant raw material is the penetration of the extractant into this material and its wetting of substances present within the cells [3]. According to Young's equation, the wetting of substances by the extractant depends on the surface tension, which can be lowered by surface-active agents (SAAs). Consequently, the use of SAAs will permit an intensification of the process of mass transfer and a faster and fuller extraction of biologically active substances from plant raw material.It has been shown previously that under the influence of SAA solutions in the extraction of essential oils from plants the surface tension of water falls and the wetting, 15enetration, and swelling of the plant material are facilitated [4]. In the production'of rutin from the buds of the Japanese pagoda tree, losses are connected with incomplete removal at the extraction stage. Thus, a single extraction under industrial conditions permits only about 60 % of rutin to be isolated [5].We have studied the influence of some SAAs on the extraction of rutin from Japanese pagoda tree buds. The swellability of the raw material was studied by the procedure of Lishtvan et al. [6]. In the experiments we used anionic (ASSAs), cationic (CSAAs), and nonionogenlc (SAAs) surface-active agents in various concentrations.It can be seen from the results presented in Table 1 that the total swellability of the buds amounted to 300% and was reached in 10-12 h in the absence of SAAs. The investigations showed that the degree of swelling and the time to reach equilibrium depend on the temperature. Thus, at 20~ equilibrium was reached in 10-12 h, and at 60~ after 2.5 h, the amount of water exceeding 215 % of the initial weight.The experimental results are well described by the equationwhere G s is the weight of raw material after saturation, k is a coefficient, and r is the time.To increase the rate of swelling we used SAA solutions with various concentrations. The maximum effect was achieved at concentrations of 0.25-0.3 %. The swelling process has an exponential nature, with the rate of penetration almost doubling.Thus, the preliminary wetting of plant material with an aqueous solution of an SAA promotes swelling, the opening up of a large number of cells, and an increase in the proportion of macropores, which considerably accelerates the processes of mass transfer in the system. It was established that with a twofold extraction of rutin from Japanese pagoda tree buds after the wetting of the raw material with a 0.25% solution of an SAA the yield of desired product amounted to 86.5%, as compared with 78.0% in threefold extraction by the existing technology. EXPERIMENTALThe swellabili...