Influence of extrusion on the feed value of flax seeds

Relevance. The wide use of extrusion for processing plant raw materials is explained by the possibility of improving the structure and increasing the availability of macronutrients of the target product. Extrusion of oilseeds is complicated by the negative effect of high lipid content on the ongoing physicochemical processes and, as a consequence, a decrease in the quality of extrudates. Along with their high lipid content, oilseeds such as flaxseed contain significant amounts of protein, soluble (mucilage) and insoluble (cellulose, lignin) fibers, which can also affect the technological properties of extrudates. As a high-energy and protein component, flax seeds are used in the feed industry. Increasing the nutritional value of flax seeds and their safety will expand the range of biologically active additives for the production of feed. The purpose of this work is to study the effect of extrusion on the feed value of flax seeds.Methods. For the research we used unmilled oil flax seeds produced in 2020. Flax seeds were processed by wet extrusion: the raw material was preliminarily moistened to 17% at 80 °C; extrusion process parameters — 120 °С, pressure 40 atm., duration 30 sec. Extruded flax seeds were obtained on a pilot plant of OOO “Fid-Group” (Belgorod region). Studies of extruded flax seeds were carried out on the basis of the laboratory for processing bast crops of the Federal Scientific Center for Fiber Crops (Tver).Results. A comparative analysis of the results showed a positive effect of short-term barothermal treatment, such as extrusion, on the chemical composition of flax seeds and their feed parameters. It has been shown that: the content of crude protein in extruded flax seeds increased by 3.97%, the water-soluble fraction increased by 66.18%, which indicates an increase in the biological value of the extrudate; the mass fraction of crude fiber decreased by 1.18%, which indicates an improvement in the digestibility of the extruded product; the content of mineral nutritional value increased by 12.5%; when using barothermal treatment, the nutritional value of flax seeds increased by 2.46%, metabolic energy increased by 2.19% and digestible protein increased by 4.08%; the level of indicators of the lipid complex, acid number and peroxide number, decreased by 40 and 39% respectively, which indicates a decrease in the activity of enzymes that cause hydrolytic and oxidative deterioration of the extrudate.

Physical and Mechanical Characteristics of a Pine Thermowood Composition during Barothermal Treatment

The studies are aimed at forming ideas on the structure and properties of composite materials obtained from pine wood and the processes occurring in the structure of wood tissue. The article presents the data on the influence of the conditions of barothermal treatment of pine wood samples by the method of explosive autohydrolysis on the properties of a thermowood composition. The composite material is obtained by hot pressing. The influence on density, strength and hydrophobic characteristics was studied. A series of samples was made under different conditions of the explosive autohydrolysis rigidity factor; at a temperature of 200 °C and the process duration from 0.08 to 10 min. All samples of composite material were obtained without the use of additional components. It was found that the increase in the hydrolysis rigidity factor leads to a decrease in the density of hydrolyzed wood from 440 to ~350 kg/m3. There is no fragmentation of wood samples with the selected processing parameters. Hot pressing of hydrolyzed wood obtained under conditions of low or moderate rigidity is accompanied by a linear increase in the density of the thermowood composite material from ~440 to 500 kg/m3. The consequence of a further increase in the rigidity factor is a slowdown in the rate of increase in the density of the composite material. The conditional boundary that determines the achievement of the maximum number of cross-linked intermolecular structures in the composite material corresponds to the rigidity factor of 3000–4500 min. More rigid processing conditions cause intensification of thermal degradation processes. The dependence of hydrophobic characteristics on the rigidity of the barothermal treatment conditions is complex. At the rigidity factor of 1000–3000 min, an extreme point is observed, before which the hydrophobic properties of the material deteriorate. Its water absorption and swelling increase from 50 to 130 % and from 15 to 54 %, respectively. The hydrophobic performance is significantly improved after reaching the extreme point. Water absorption and swelling reduce to ~20 % and ~10 %, respectively. Mild hydrolysis conditions do not result in a material with consistently high hydrophobic properties. The cross-linked structures are not enough to form a strong and water-resistant composition, and as a consequence, the hydrophobic characteristics deteriorate. Increasing the value of the hydrolysis rigidity factor increases the number of active components. Additional intermolecular bonds formed during pressing improve hydrophobic characteristics. The obtained results can be used in the creation of models of processes occurring in the structure of lignocellulose substance during explosive autohydrolysis and in the preparation of composite materials based on it. Optimal parameters of barothermal treatment for obtaining composite materials with specified physical and mechanical characteristics can be determined. Barothermal treatment of solid pine wood by explosive autohydrolysis contributes to the occurrence of chemically active components in the structure of wood tissue. Their number depends on the rigidity of the processing conditions. The properties of the resulting thermowood composition depend on the conditions of explosive autohydrolysis.

The Technology for Manufacturing HighStrength Pipe-Concrete Bearing Elements to Increase the Stability of Underground Structures

It is proposed to use high bearing small-size pipe-concrete units in the construction of underground geotechnical structures instead of large-sized reinforced concrete units (support blocks, pylons, columns, etc.). The analysis of the methods of manufacturing pipe-concrete units, their advantages and disadvantages is conducted. The process flowchart for manufacturing pipe-concrete units with barothermal pre-stressing of a concrete mixture in a steel pipe was developed to ensure the collaboration of a steel pipe and a concrete core and increase its strength. Experimental research in barothermal treatment of a concrete mixture in a steel pipe was performed using the laboratory model of a pipe-concrete unit, which showed the efficiency of the proposed technological scheme for the production of pipe-concrete units. The lines for further research in the development of a method for determining the optimal parameters of the technological scheme for manufacturing pipe-concrete units with barothermal pre-stressing of a concrete mix are planned.