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Sirvi Autor "Bandura, Valentyna" järgi

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  • Pisipilt
    Kirje
    Application of the differential scanning calorimetry method in the study of the tomato fruits drying process
    (Estonian Academic Agricultural Society, 2020) Kuznietsova, Inha; Bandura, Valentyna; Paziuk, Vаdym; Tokarchuk, Oleksii; Kupchuk, Ihor
    Structural changes in the process of heating fresh fruit, sundried fruits and powder obtained from the dried tomato fruits were studied by differential scanning calorimetry method application. The kinetics of the shredded fruits in the dryer proves the prospects for using convective drying, which is performed for 295 minutes. The kinetic coefficients of drying and critical moisture content in the crushed fruits of tomato were determined. The kinetic coefficients were determined by the graphicalanalytical method: a = 0.839, ln(α) = 1.3 and α (1 s–1 ) = 0.262. It was determined that the critical maximum moisture content for drying the shredded fruits of tomatoes is 1.503% mm–1 , after what the process of combustion of vegetable tissue begins. The application of the differential scanning calorimetry (DSC) method allowed the fuller study of the mechanism of drying the fruits of tomato in different condition: fresh, sundried and dried. It was determined that the greatest amount of energy is consumed to remove free moisture (1,993 J g–1 ) from the fresh tomatoes. At the same time, when being cooled, crystallization in plant tissue occurs with the release of energy in the amount of 0.03922 J g –1 . When drying the previously sun-dried tomatoes the process of moisture removal and the partial decomposition of the compounds that are unstable to temperature is completed. At the same time, at the 129.61 °C temperature in the powder obtained from the fruits of tomatoes, melting of carbohydrates and other compounds occurred. Thus, this confirms the need to observe the normalized value of the mass fraction of moisture in the powders in the process of their packaging, storage and use. The basic technological system of production of powder from dried fruits of tomatoes is offered.
  • Pisipilt
    Kirje
    Case study: Dynamics of sunflower seed movement in the vibrating tray of the infrared dryer and its influence on the drying process
    (Estonian Academic Agricultural Society, 2021) Bandura, Valentyna; Yaroshenko, Leonid; Fialkovska, Larisa; Kondratyuk, Dmytro; Palamarchuk, Vladyslav; Paladiichuk, Yurij
    Analysis of researches on the study of the material particle movement on the vibrating surface of the container machine intended for seed drying in the infrared field is carried out. Comparison of traditional devices for dehydration of raw materials with energy supply of infrared irradiation is performed. It is shown that current tendencies of the development of heat and mass transfer equipment are connected with the use of electromagnetic generators of infrared energy. The purpose of the work is to study the process of movement of sunflower seeds on a vibrating tray dryer. To achieve this goal, a dynamic scheme of the vibrating tray has been proposed and theoretical and experimental studies of the process of grain movement have been carried out. It has been established that when the speed of drive electric motors increases from 950 to 970 rotations per minute, the speed of vibro-transportation increases as well, but when reaching a certain value of speed, under a further increase in speed, the speed of vibro-transportation decreases. Experimental studies have allowed to specify the design parameters of vibrating trays and select rational parameters of the technological process of drying, namely the oscillation frequency of the vibrating tray, which is f = 100 s–1.
  • Pisipilt
    Kirje
    Identification of mathematical description of the dynamics of extraction of oil materials in the electric field of high frequency
    (Estonian Academic Agricultural Society, 2021) Bandura, Valentyna; Kotov, Boris; Gyrych, Sergey; Gricshenko, Volodymyr; Kalinichenko, Roman; Lysenko, Oksana
    One of the most important stages of the technological process of extraction of target components from oilseeds is extraction. This stage lasts the longest, and therefore, it generally determines the speed and cost-effectiveness of the whole process. A promising direction for effective organization of the extraction process is involving microwave technologies, the use of ultra-high frequency electromagnetic field (EHF) microwave energy directly in the technological process. The complex nature of the interaction of the factors that determine the intensity of the extraction process in the microwave field does not allow establishing (create) an exact mathematical model of extraction. We propose a method of parametric identification of the mathematical description of the extraction dynamics. This method allows determining the kinetic coefficients of the process from one experimental experiment on the existing installation. A simplified process mechanism was chosen for the study and a general description of the phenomena of heat and mass transfer in a capillary-porous body was used for the known general description. The parameters of the obtained model were identified according to experimental studies. The thus obtained model of non-stationary processes can be used to optimize the parameters and automate the technical means of extraction of oil materials.
  • Pisipilt
    Kirje
    Investigation of properties of sunflower and rapeseed oils obtained by the soxhlet and microwave extraction methods
    (Estonian Academic Agricultural Society, 2022) Bandura, Valentyna; Fialkovska, Larysa; Osadchuk, Petro; Levtrynskaia, Yuliia; Palvashova, Аnna
    The main purpose of the study was to evaluate the possibility of replacing hexane, which is traditionally used for the extraction of vegetable oils, with ethanol as a safer solvent when extracting oil from sunflower meals and rapeseed in the microwave field. Thus, the influence of the solvent type on physicochemical characteristics of oil and the low-fat meal was studied. The main indicators of the composition and quality of sunflower and rapeseed extraction oil were studied. The quality of oil and ways of its use in food products are mostly determined by its fatty acid composition. Analysis of the fatty acid composition of the oil was performed by the method of gas chromatography using a column HP-88 100 m* 0.25 mm*0.20 µm. The possibility of using oil in food was established by conducting pilot laboratory studies and investigating changes in physicochemical parameters during storage. The extraction by the Soxhlet method (hexane as a solvent) was compared with the method of extraction of raw materials in a microwave field (ethyl alcohol as a solvent). Studies of physicochemical parameters indicate the degree of oil oxidation (determination of peroxide and anisidine values). The peroxide value is an indicator of the content of primary oxidation products. The peroxide value of the oil obtained by the method of Soxhlet extraction (hexane as a solvent) was 5.0 (½O mmol) kg–1 . The peroxide value of the oil obtained by extraction in a microwave field (ethyl alcohol as a solvent) was 3.8 (½O mmol) kg–1 . The anisidine value is an indicator of the content of aldehydes in vegetable oils (secondary oxidation products). The anisidine value of the oil obtained by the method of Soxhlet extraction (hexane as a solvent) was 0.3 s.u. The anisidine value of oil obtained by extraction in a microwave field (ethyl alcohol as a solvent) was 0.2 s.u. Comparing the data of peroxide and anisidine values, it can be argued that the oil obtained by extraction of raw materials in a microwave field (ethyl alcohol as a solvent) had the best indicators. The acid value is one of the main qualitative indicators that characterize the degree of oil freshness. The acid value of the oil obtained by the method of Soxhlet extraction (hexane as a solvent) was 3.1 (mg KOH) g –1 . The acid number of the oil obtained by extraction in a microwave field (ethyl alcohol as a solvent) was 2.1 (mg KOH) g –1 . A comparison of the acid values of oils extracted from the raw material by different extraction methods shows that the oil obtained by the method of extraction of raw materials in a microwave field using ethyl alcohol as a solvent has the best acid value. Studies have shown that the oil, which was obtained by extraction of raw materials in a microwave field using ethyl alcohol as a solvent, had the best resistance to oxidation during storage (three months).