The extrusion process advantage of agricultural raw materials processing into food and feed over traditional technologies is the high specific productivity, energy efficiency and versatility of use. The presence of a large number of control factors and influence on the raw materials quality, such as operating parameters and structural elements, make extrusion a difficult reproducible process when scaling or moving from one installation to another. But this aspect is the reason for the maximum flexibility of extrusion systems and the possibility of their continuous improvement. One of the ways for the extrusion technology development is the improvement of equipment and design solutions in the field of energy saving. Investigations of the thermoplastic extrusion process of wheat grinding with the application of the recovery of steam heat generated by a special configuration of screw elements and its degassing with the feeding into the processed material were carried out in the work. The modernized extruder Werner & Phleiderer Continua 37, supplemented by a developed recuperative unit and a steam line, was used to achieve this goal. An assessment of changes in energy consumption during steam recovery was carried out. The physicochemical properties of the experimental and control samples of wheat grain extrudates obtained under various operating conditions were investigated and determined. It was found out that the steam recovery mode is a statistically significant reason for increasing the humidity of the extruded product from 3.8 to 5.0 bulk density - by 15% relative to the mode without recovery. A decrease in the explosion coefficient and the water-holding capacity of the extrudates during operation in the regenerative mode of extrusion was noticed. The presented method with additional thermal effects on the processed raw materials allows us to expand the technological capabilities of the process of thermoplastic extrusion in obtaining products of various functional and technological purposes.

extrusion, agricultural raw materials, steam recuperation, specific energy consumption, technological properties

1. Ostrikov A.N., Magomedov G.O., Derkanosova N.M., Vasilenko V.N. et al. Technology of extruded products. Saint-Petersburg, Prospekt nauki, 2007. 202 p. (in Russian).

2. Sharikov A.Y., Rimareva L.V., Stepanov V.I., Ivanov V.V. et al. Influence of cereal extrusion variables on efficiency of biotechnological processes for agroculture processing industries. Storage and Processing of Farm Products. 2012. no. 5. pp. 18–21. (in Russian).

3. Riaz M.N. Introduction to extruders and their principles. In: Extruders in food applications. Boca Rafon, FL, CRC Press, 2000. pp. 1–23.

4. Voronina P.K. Practical perspectives for thermoplastic extrusion starchcontaining grain feedstock in shaping the quality of food products. Innovative machinery & technology. 2015. no. 3. pp. 5–9. (in Russian).

5. Didyk T.A. Reducing the energy intensity of press extruders. Vavilov Readings – 2004: materials of the All-Russian Scientific and Practical Conference. Saratov, Federal State Educational Institution of Higher Professional Education “Saratov State Agrarian University”. 2004. pp. 49–52. (in Russian).

6. Novikov V.V., Kharybina N.A. Justification of the design parameters of the working bodies of the extruder feeder. Bulletin of the Samara State Agricultural Academy. 2011. no. 3. pp. 113–118. (in Russian).

7. S?rensen M., Nguyen., Storebakken, T., ?verland M Starch source, screw configuration and injection of steam into the barrel affect the physical quality of extruded fish feed. Aquaculture Research. 2010. vol. 41. no. 3. pp. 419–432. doi: 10.1111/j. 1365–2109.2009.02346.x

8. Pacheco P.D.G, Putarov T.C, Baller M.A., Peres F.M. et al. Thermal energy application on extrusion and nutritional characteristics of dog foods. Animal Feed Science and Technology. 2018. doi: 10.1016/j.anifeedsci.2018.07.003

9. Roke G.J., Plattner B., Souza E.M. de. Feed extrusion process description. Revista Brasileira de Zootecnia. 2010. vol. 39. pp. 510–518. doi:10.1590/S1516–35982010001300055

10. Levine L. Using Injection in Extrusion: The Thermal Value. Cereal Foods World. 2006. vol. 51 (6). pp. 355. doi: 10.1094/CFW 51–0355

11. Wenger M., Wenger L., Rokey G.J., Spellmeier A.C. Method and apparatus for producing fully cooked extrudates with significantly reduced specific mechanical energy inputs. Patent US, no. 07521076, 2009.

12. Canjyal G., Hanna M.A., Supprung P., Noomhorm A. et al. Modeling selected properties of extruded rice flour and rice starch by neural networks and statistics. Cereal Chemistry. 2006. vol. 83. no. 3. pp. 223–227.

13. Potter R., Stojceska V., Plunkett A. The use of fruit powders in extruded snacks suitable for Children's diets. Lebensmittel-Wissenschaft und Technologie. 2013. vol. 51. pp. 537–544. doi:10.1016/j.lwt.2012.11.015