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The focus of this study is on the physical quality traits and starch composition of various maize kernel genotypes grown in Serbia. Furthermore, the aim was to determine the relationship among these quality traits. Results obtained from the Stenvert hardness test showed great variability among the maize samples. The portion of the hard endosperm fraction (HE) ranged from 53.29% to 76.28%. Test weight (TWt) and 1000-kernel weight (KWt) of 10 different ZP maize genotypes ranged from 782.69 to 907.39 kgm-3 and from 128.40 to 376.50 g, respectively. The specialty maize genotypes had the highest content of amylose (27.8% and 28.9%). Yellow dent genotype, ZP 606, had the lowest amylose content in the kernel (22.3%). The results suggested that the composition of starch granule differed depending on the hardness of the endosperm. The amylose content was highly correlated with the physical traits such as TWt, KWt, density and HE.

Aflatoxins (AFs), fumonisins (FUMs), zearalenone (ZEA) and deoxynivalenol (DON) have been recognized as major contaminants of maize. Therefore, the presence of AFs, ZEA, DON and FUMs was examined in a total of 100 maize samples from the Autonomous Province of Vojvodina. Sample analyses were performed using the Enzyme Linked Immunosorbent Assay method. The results obtained indicate that 74 % of the maize samples were contaminated with FUMs (540.1-5076 μg/kg), followed by 52 % contaminated with DON (275.2-882.1 μg/kg), 15 % contaminated with ZEA (35.6-183.5 μg/kg) and 5 % contaminated with AFs (2.28-4.31 μg/kg). Although 78 % of the samples were contaminated with at least one mycotoxin, the concentration of FUMs exceed the maximum level (ML) proscribed by the Serbian regulations only in 4 % of the samples. Furthermore, the detected concentrations of AFs, ZEA and DON were in accordance with national regulations. This study is the first research of its kind on the presence of AFs, ZEA, DON and FUMs in maize harvested in the APV in 2016.

Extrusion technology is commonly used in fish feed production. In cooking zone of the extruder barrel, sufficient energy is imparted to gelatinize starch and denature proteins. Time in which material will be exposed to high temperatures and pressures depends of the time that material spends in the cooking zone. Length of the cooking zone can be varied by changing independent extrusion variables. In this investigation, screw speed, amount of added oil and total area of die openings were varied. The most severe conditions of 0% of added oil, screw speed of 420 rpm, and 50 mm2 of total area of die openings, resulted in the highest temperatures at measuring points (T1 = 102.6°C, T2 = 104.0°C, T3 = 110.3°C, T4 = 118.8°C). It can be concluded that by changing independent extrusion variables, temperature profile in the barrel can be modified in order to achieve optimal extrusion conditions.

In this paper, effect of moisture addition during steam conditioning of feed on pellet quality and electrical energy consumption in pelleting process was investigated. Complete mixture for pigs II (from 15 to 25 kg) was conditioned up to moisture content of 15.97 %, 19.40 %, and 21.88 %. Physical properties examined in purpose of pellet quality determination were hardness and durabillity of pellets. Pellets, produced from conditioned material with higher content of moisture, were more stabile and less hard. Higher moisture content of conditioned material resulted in decreasing of energy consumption during pelleting process. Electrical energy consumption in pelleting process, along with achieving targeted pellet quality, could be significantly lower by choosing proper conditioning process parameters.