Features of Extraction of Valuable Components from Plant Raw Materials

In practical terms, the extraction of CO2-extractive substances from secondary grain processing resources makes it possible to obtain high-quality products [1]. New ways to intensify the process of extracting valuable components from raw materials are being implemented relatively quickly at the existing extraction plant [2]. The development of modern sub-and supercritical technologies has been recognized not only in the country, but also abroad [3]. The process of obtaining CO2-extracts from grains and nuts can be supplemented with pre-enzymatic and extrusion processing [4]. The prototype for obtaining CO2-extracts has always been essential oils obtained by steam distillation [5]. However, the high temperature of obtaining essential oils leads to the destruction of some of the thermolabile substances. Automation of technological processes plays an important role in increasing the efficiency of extraction production [6,7].

Figure 1: Scheme for obtaining essential oil from vegetable raw materials.

The simplest and most affordable way to process aromatic raw materials is steam distillation (Figure 1). Essential oils are widely used in the perfume and cosmetics industry. The most suitable solvent for essential oils and related substances was liquefied carbon dioxide. Figure 2 shows the line for producing carbon dioxide from flue gases.

The use of liquid carbon dioxide as an extractant has a long history. Scientists and specialists of the scientific and pedagogical school operating at KubSTU made a significant contribution to the development of this technology. Figure 3 shows a diagram of a subcritical CO2-extraction unit operating in the range of temperatures from +10 to +25 oC and pressures from 5 to 6.5MPa. Another option for processing plant raw materials is supercritical fluid extraction, in which the extractant is a dense gas at a temperature of 40 to 60 oC and a pressure of 10 to 60MPa. Thus, the extraction industry has made a transition to high technologies for extracting target components from raw materials with liquefied and compressed carbon dioxide (Figure 4).

Figure 2: line for producing carbon dioxide from flue gases. 1-firebox, 2-heat exchanger, 3-compressor, 4-CO2- production plant, 5-CO2-collector, 6-CO2-tanker.

Figure 3: Scheme of subcritical CO2 extraction plant.

Figure 4: Diagram of a fluid CO2-extraction unit.

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3. Medvedev AM, Magomedov AM (2019) Modern sub-and supercritical CO₂-technologies. In the collection of materials of the 24^th International Scientific and Practical Conference "Innovation-2019". Tashkent, Uzbekistan, pp. 382-383.
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5. Puchkova TV, Gurinovich LK, Tarasov VE (2020) Essential oils: chemistry, technology, analysis, application. School of cosmetic chemists, Moscow, Russia, p. 264.
6. Silinskaya SM, Malashenko NL (2019) Control over the state of carbon dioxide by means of digitalization. In the collection of materials of the international scientific and practical conference "Exclusive technologies for the production of meat, dairy and fish products". KubSTU, Krasnodar, Russia pp. 190-193.
7. Silinskaya SM, Narizhnaya NYu, Tkachenko VV (2017) Methods and means of evaluating the effectiveness of technical equipment for the system of CO₂-extraction of plant raw materials. Polythematic network electronic scientific journal of Kuban State Agrarian University, Krasnodar, Russia, 132: 1354-1365.