The objective of the present study was to develop a supercritical fluid extraction (SFE) method, suitable for extraction of total oil content from linseed, and to be used as a preparative technique for fatty acid determination. Optimum conditions (volume of added ethanol as a co-solvent, dynamic extraction time (DET), and pressure) were predicted in order to obtain the maximum yield of the extract. Response surface methodology (RSM) and central composite rotatable design (CCRD) were used for modeling the process. Variable values ranged as follows: co-solvent 0-1 mL, DET 36-60 min, and pressure 45.57-62.05 MPa (6000-9000 psi). Effects of co-solvent volume and extraction pressure were well described by simplified polynomial equation (R 2 ¼ 0.85), since DET had no significant influence ( p>0.05) on the extract yield. The maximum yield of oil, calculated from experimental results, was obtained with 1 mL of co-solvent, and pressure of 62.05 MPa. Optimized conditions were used for extraction of oil from four samples of linseed, ground to pass through 1, 2, 3, and 4 mm-sieve, to determine adequate granulation for SFE. Finally, results for yield and fatty acid composition of the extract obtained using SFE were compared with the results of Soxhlet extraction.Practical applications: The obtained extracts can be used for fatty acid analysis, since they have not been damaged and their fatty acid compositions have not been degraded by reagents or aggressive extraction conditions. It is shown that the selection of appropriate milling equipment for grinding of samples is necessary to achieve adequate granulation and avoid fractionation of sample.

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Summary: Linseed is a good source of linoleic (LA, 18:2, n-6) and especially α-linolenic acid (ALA, 18:3, n-3), ω6 and ω-3 polyunsaturated fatty acids (PUFA), which are essential because mammals, and therefore humans, cannot endogenously synthesize them and must adopt them exogenously from dietary sources. In spite of its high nutritive value, linseed has not been effectively exploited in animal feeding, due to the fact that it contains antinutritive components, which are cyanogenic glycosides (CG) and antivitamin B6 (linatine). CGs are a major limitation in application of linseed and its meal in animal nutrition. The objective of the study was to investigate effect of microwave heat treatment on the content of hydrogen cyanide, and consequently cyanogenic glycosides in linseed. Operating frequency of microwave oven was 2450 mHz, and working power was 240W, 400W, 560W and 800W. Samples were treated for 0, 3, 6 and 10 minutes for every working power. When microwave power of 560 W and 800 W was used for 6 min and longer, linseed samples were burned and damaged, therefore these treatments should not be used. Minimal time of heating with microwave power of 400W, which would provide reduction of HCN content under allowed limits (250 mg/kg of linseed), was determined graphically using three-dimensional contour plot graph and it was 290 s (4 minutes and 50 s). This regime is recommended for treating linseed before usage as a feed compound.

This paper shows the results of screening of mycotoxins in animal feed originating from the region of Vojvodina. Permanent screening is needed on all levels of production and storage, as well as the use of known methods to reduce mould contamination or toxin content in feedstuffs and feed. A total of 56 representative samples were collected from feed companies from the region of Vojvodina. Samples were collected during February 2009. The collected samples included 41 samples of feedstuffs (soybean, soybean meal, soybean grits, soybean cake, maize, sunflower meal, barley, wheat feed flour, rapeseed meal, dehydrated sugar beet pulps, alfalfa meal, yeast, dried whey, fish meal, meat-bone meal) and 15 samples of complete feedingstuffs. The amounts of aflatoxins, ochratoxin A, zearalenone, fumonisin and deoxynivalenol were determined. Screening method for the analysis was done using Neogen Veratox® testing kits. The test itself is a competitive direct enzyme-linked immunosorbent assay (CD-ELISA). Mycotoxins were present in 71.4% of the samples, but the values determined were below the maximum allowed limits for both Serbian and EC reference values. Zearalenone was found with the highest incidence (57.1% of samples), followed by ochratoxin A (37.5%), fumonisin (33.9%), deoxynivalenol (14.3%) and aflatoxins (3.6%)

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