1. Dragan Živančev, Slavko Filipović, Šandor Kormanjoš, Jelena Filipović, Marijana Sakač Institute for food technology, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia ACKNOWLEDGEMENTS This work was supported by Ministry of Science and Technological Development, Republic of Serbia, the Project No. 20068 (Foods for Consumers with Special Demands and Needs), ABSTRACT Food production worldwide is one of the major challenges of the modern life. Therefore, novel technology processes are applying to increase the nutritional value of raw materials, food and feed. One sophisticated technological process for improving nutritional value and quality of raw materials is extrusion. Heat treating of cereals is used for improving their nutritional, hygiene, physico-chemical and other properties, i.e. it increases the nutrient value of some nutrients, improve sensory properties (i.e. increasing, "sweetness" of extruded product), provides the microbiological safety of the products and inactivate possibly present thermo-labile nutrients. This paper presents the technico- technological parameter of the process, physico-chemical composition and microbiological safety of raw materials before and after extrusion. CONCLUSIONS Stable products were obtained by extrusion of whole-milled corn and light buckwheat flour mixture (ratio 9:1) at 115 ºC and 150 ºC. Application of higher extrusion temperature caused greater changes in physico-chemical properties of extrudates. Statistically significant changes in starch content, total and reducing sugar content, crude fat content and test wieght were detected for extrudate at 150 °C in comparison with extrudate obtained at lower temperature (115 °C) and with nonterated mixture. Corn extrusion at 90 and 95 ° C leads to physico-chemical changes in treated material, primarily to changes in the structure of proteins, which is demonstrated through significantly different levels of NSI, and accompanied by statistically significant differences of crude protein content. Dry extrusion of corn resulted in statistically significant changes of crude fat content in extruded product in comparison to untreated corn. The starch content of extruded corn was statistically significantly lower, with the consequent increase in the content of total sugar and reducing sugar. Extruded enriched corn meal feed have higher nutritional value in comparison to the meal which is not extrude, also it is microbiological safe. Table 1. Particle size distribution of whole-milled corn and light buckwheat flour Sieve mash Ø (mm) Sieve overtails (%) Whole-milled corn Light buckwheat flour/ 2.0019.1- 1.2525.9- 1.009.9- 0.6313.60.2 0.2519.98.5 0.12511.532.6 0.630.146.8 Bottom-11.9 Table 2. Chemical composition of extruded products and raw materials Quality characteristic Whole- milled corn (%) Light buckwheat flour (%) Mixture (90% whole-milled corn: 10% light buckwheat flour) Extruded mixture at 115 °C Extruded mixture at 150 °C Moisture 17.3211.7016.7613.309.63 Crude proteins 7.4411.387.838.448.50 Crude fat 3.442.713.373.402.92 Starch 62.1269.1662.8265.8766.90 Total sugars 1.441.481.442.163.60 Reducing sugars 0.960.590.920.860.48 Table 3. Chemical composition of Chemical composition of extruded products and raw materials in dry matter Quality characteristic s Whole- milled corn (%) Light buckwheat flour (%) Mixture (90% whole-milled corn: 10% light buckwheat flour) Extruded mixture at 115 °C Extruded mixture at 150 °C Crude proteins 9.00 a 12.89 c 9.41 ab 9.73 b 9.41 ab Crude fat 4.16 a 3.07 b 4.04 a 3.92 ac 3.23 bc Starch 75.13 a 78.32 d 75.47 ab 75.97 b 74.03 c Total sugars 1.74 a 1.68 a 1.73 a 2.49 b 3.98 c Reducing sugars 1.16 a 0.67 bc 1.11 a 0.99 ac 0.53 b Table 4. Particle size distribution of milled corn Sieve opening (Ø, mm) Sieve overtails (%) 2.0014.9 1.2515.4 1.008.1 0.6318.5 0.2534.8 0.1258.3 0.063- Bottom- Tabela 5. Chemical composition of milled corn and extruded corn at 90 and 95 °C in dry matter 22 Quality characteristic Corn (%) Extruded corn at 90 °C Extruded corn at 95 °C Crude proteins9.25 c 9.07 b 8.97 a Crude ash1.83 b 1.56 a 1.58 a Crude fiber3.45 c 2.47 a 2.80 b Crude fat4.80 c 2.08 a 2.66 a NSI15.91 c 6.66 a 6.21 a Starch70.90 c 67.06 b 64.98 a Total sugar1.00 a 3.99 b 4.12 b Reducing sugar0.40 a 0.42 a 0.45 a Table 8. Particle size distribution of enriched corn meal and extruded enriched corn meal Sieve opening (Ø, mm) Sieve overtails (%) Corn meal Extruded corn meal 4.000.000.30 2.000.503.00 1.255.009.00 1.0011.857.85 0.6323.8534.30 0.2525.7536.45 0.12527.558.20 0.635.000.90 Bottom0.500.00 Table 7. Physical and chemical characteristics of enriched corn meal and extruded enriched corn meal (T = 95 ° C) Quality characteristics Corn meal Extruded corn meal at 95 ° C Water content (%) 14.58.50 Crude protein content (%) 1111.0 Celullose content (%) 3.53.50 Starch content (%) 5550.68 Ash content (%) 4.02.50 Fat content (%) 7.57.50 Phosphorous (%) 0.50 Calcium (%) 0.20 β-carotene content (mg/kg) 1.101.11 Test weight (g/l)526.1359.0