Reduction of deoxynivalenol during durum wheat processing and spaghetti cooking

The reduction of deoxynivalenol (DON) during durum wheat processing and spaghetti cooking was investigated in nine samples of durum wheat contaminated with DON under field conditions (either naturally contaminated or artificially inoculated with Fusarium) at levels ranging from 0.3 to 13.1 microg/g. A consistent reduction of DON levels was observed during each of the processing steps from uncleaned durum wheat to cooked spaghetti. With respect to the uncleaned wheat, the average levels of DON were 77% in cleaned wheat, 37% in semolina, 33% in spaghetti and 20% in cooked spaghetti, with relative standard deviations of 11%, 13%, 12% and 8%, respectively. Average DON levels in the screenings, bran and fine middlings were 4.1-, 1.6- and 0.6-fold, respectively, relative to the uncleaned wheat. DON was almost completely recovered from spaghetti after cooking, with a repartition between cooked spaghetti (without the corresponding DON amount from absorbed water) and cooking water generally in favour of the latter. An increased DON leaching into the cooking water was observed when a higher water to spaghetti ratio was used during cooking. This study strongly supports the basis of previous knowledge on DON distribution in durum wheat, semolina and pasta products, and concludes that the retention level of DON from grains on the market to cooked pasta in the plate can be conservatively assessed at 25% or less.