Distributions of some toxic contaminants in the milling products, during the milling process

Research conducted by Schollenberger et al. on 60 samples of wheat flour from a mill in South-West Germany, showed that the degree of contamination with mycotoxins such as deoxynivalenol (DON), nivalenol (NIV), 3 – and 15-acetyldeoxynivalenol, HT-2 toxin (HT -2), T-2 toxin (T-2), fusarenona X (FUS-X), zearalenona (ZEA), α- and β-zearalenol (α-and β-ZOL), decreases as the ash content decreases. This fact suggests that most of the investigated contaminants are in the areas situated outside the grain. Oh-Kyung Kwon et al. have shown that there is a dynamic of the content of mycotoxins in cereals such as barley and wheat, characterized by decreasing the amount of mycotoxins in the flour, compared with bran. researches have also shown that different technological treatments applied in order to reduce the content of mycotoxins are not so effective. Thus, the alcoholic fermentation of the cereal products causes a significant further decrease of the content of mycotoxins, than the operations of simple washing with water, or boiling. The content of mycotoxin also decreases with increasing number of washing of grain products with water. Various studies on wheat flours showed that, although the level of contamination by mycotoxins varies from one agricultural area to another, or even from one harvest to another, the impact on human health is extremely important.

Abdullah et al. tested 83 samples of wheat flour in Malaysia and determined average amounts of aflatoxin B1 up to 25.6 ppb, aflatoxin B2 amounts between 25.0-289.4 ppb and aflatoxin G2 in concentrations ranging from 16.3 to 436.3 ppb [1]. Halt reported an average content of 16.3 ppb aflatoxin B1 for a total of 475 samples of wheat from Croatia, and Aydin et al. determined for 100 samples of wheat flour derived from 7 areas in Turkey, a content of total aflatoxins ranging between 0.05 and14.01 ppb total aflatoxin.

A study made by Gyrai et al. regarding 41 samples of Turkish wheat, showed that 59% of them were contaminated with aflatoxins, most of the contaminants being aflatoxin B1 and aflatoxin G2 . Ayalew, who studied more than 350 samples of different cereals (wheat, barley, sorghum, etc.), found that nearly 9% of them were contaminated with total aflatoxins in quantities up to 26 ppb .

In most areas within Eastern Europe, the contaminant with the highest exposure is considered to be Ochratoxin A. Correlation studies of ochratoxin A with the Balkan endemic nephropathy have shown significantly higher quantities of ochratoxin A in the cereal products from endemic areas within the compared products grain from not endemic areas. Aydin et al. determined quantities of ochratoxin A ranging from 0.025 to 10 ppb in the samples of wheat flour obtained from Turkish wheat, and Zinedine et al. have identified a contamination rate of 40% with a maximum level of 1.73 ppb in samples of wheat from Morocco. Araguas et al. reported a degree of contamination with ochratoxin A of 23.4% for 107 samples of Ethiopian wheat, with a maximum level of contamination ppb µg / kg . Araguas et al. have identified 58 wheat samples contaminated with ochratoxin A, from a total of 115, in a medium level of contamination of 0.219 ppb . Finally, Muscarella et al. identified in Italian grains a degree of contamination of 15.8% and limits of variation in the level of contamination with ochratoxin A between 0.2 and 3.9 ppb .

In terms of heavy metal content, the results highlighted in literature vary significantly both from one area to another, and from one harvest to another. Thus, investigations carried out on a large number of samples of wheat flour in Japan by Shimbo et al. showed a geometric average of Cd content of 0.0019 ppm, respectively values of Pb content between 0.002-0.003 ppm . Previously, a similar study conducted in China, highlighted for the wheat flour samples an average value of the Pb content of 0.0288 ppm.

In a study regarding the content of heavy metals in grain produced and imported in Yemen, Al-Gahr et al. determined the average amounts of Pb between 0.257 and 0.367 ppm for native wheat, respectively 0.346 ppm for the wheat imported from the U.S.A. In terms of Cd, the results ranged between 0.246 and 0.296 ppm for the wheat produced in Yemen and 0.117 ppm for wheat from the U.S.A.

In the Middle East, Salama and Radwan determined an average content of 0.131 ± 0.02 Pb and 0.398 ± 0.180 ppm Cd for the the grains sold on the Egyptian market. Studies made so far suggest that the level of contaminants decreases in the processed agricultural products against the raw material source, but the dynamics of this phenomenon is shaped by factors relating to the nature and complexity of each technological process.

We processed a batch from the Romanian wheat of the 2008 harvest in the mill, obtaining flour type 550, flour type 800 and bran. Both for the initial batch of wheat, and for each product obtained after its processing, we analyzed: moisture, ash content, total content of aflatoxins, ochratoxin A content and the content of heavy metals (cadmium and lead). We identified total amounts of aflatoxins from 3.74 ppb in flour type 550 to 87.71 ppb in bran, when the content of ochratoxin A and heavy metals situated below the limits set by the European health legislation. We also noted that the dynamics of the concentration of contaminants was correlated with the dynamics of the extraction degree, namely: higher concentrations of contaminants were identified in the products of higher extraction.

Full article: 1220tamba


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