Feed Planet Magazine Issue-Sayı: 17 March/April-Mart/Nisan 2019

SPECIAL COVER • ÖZEL DOSYA 70 FEED PLANET /MARCH-APRIL 2019 • MART-NİSAN 2019 TAHIL TEMİZLİĞİNİN ETKİSİ Mikotoksinler, normalde bakterileri etkisiz hale getirmek için uygulanan ısı yöntemi ile kolay bir şekilde tahrip edilemeye- cek kadar dirençli kimyasal bileşiklerdir. Tahıldaki mikotoksin seviyelerini düşürmek adına, kirli kırık parçaları fiziksel olarak temizleyebiliriz. Tipik olarak toplam tahılın sadece küçük bir kısmını teşkil eden kırık parçalar kirlenmenin çoğunun kayna- ğıdır. Bu kırık parçaları ayırarak gruptaki mikotoksin seviyesi bir bütün olarak net bir şekilde azaltılabilir. Toz, küçük veya kırık parçaların yanı sıra düşük yoğunluklu ve büzülmüş çekir- dekler tipik olarak yüksek bir mikotoksin seviyesi içerir. Genel- likle, kirli tahıllar, renk kusurları, yüzeyde değişiklikler veya şekil deformasyonları gibi küf hastalığının görsel belirtilerini taşırlar. Şekil 2’de gösterildiği gibi, toz ve kırık taneler, boyut ayrımı ve havalandırma ile ve düşük yoğunluklu taneler, yoğunluk ayrımı will contain most of the contamination. By removing these fractions, the mycotoxin level of the lot as a whole can be clearly reduced. Dust, small or broken fractions, as well as low-density and shrivelled kernels typically contain a high mycotoxin level. Often, contaminated grains will show vi- sual signs of mould infection, such as colour defects, sur- face modifications, or shape deformations. As illustrated in Figure 2, dust and broken kernels can be removed by size separation and aspiration, and low-density kernels by den- sity separation. Finally, kernels with visual signs of contami- nation can be removed by optical sorting. TRIALS IN CORN Bühler is currently taking part in the Horizon 2020 proj- ect MycoKey, where it has conducted industrial-scale grain cleaning studies together with the Institute of Sciences of Food Production (ISPA) to verify the mycotoxin reduction ef- ficiency of grain cleaning. One of the many studies we per- formed was on corn (maize) with different levels of aflatoxin contamination of 10 μg/kg and 20 μg/kg. The trials were performed on batches of 3 tons each, which were cleaned by size separation in conjunction with aspiration and opti- cal sorting. After cleaning, total aflatoxin contamination was found to have been reduced to below 4 μg/kg, resulting in an overall reduction rate of 70-95% with a total reject rate around 10%. This means the product quality was improved from biomass and feed grade to food grade. A previous study on wheat from 2012 shows similarly good results. Raw wheat with a contamination level of 4000 μg/kg de- oxynivalenol was cleaned by size separation in conjunction with aspiration and optical sorting to a level of 1200 μg/kg. This translates into an overall reduction rate of 70% (Figure 3). Further processing of the grains by milling lowered the contamination level further still to 600 μg/kg, meaning a total reduction rate of 85%. Schematic illustration of mycotoxin mitigation along the process chain. Proses zinciri boyunca mikotoksin azaltmanın şematik görünümü Depiction of grain fractions that typically contain high myco- toxin levels and how they can be removed. Tipik olarak yüksek mikotoksin seviyelerini içeren tahıl parçalarının ve bunların nasıl çıkarılabileceğinin tasviri.