Ozone treatment efficiency on Fusarium graminearum and deoxynivalenol degradation and its effects on whole wheat grains (Triticum aestivum L.) quality and germination

The contamination of wheat grains by Fusarium graminearum is directly associated with deoxynivalenol (DON) production. In order to overcome fungal growth, ozone gas (O-3) has been widely used in food laboratory trials, but the application of O-3 at high doses may affect grain quality attributes. The objective of this study was to assess the efficacy of O-3 treatment on wheat grains artificially contaminated by F. graminearum and DON. In addition, several physical and biochemical properties after treatment were investigated. The tests were performed in laboratory pilot cylinders containing grains, divided into control groups (no O-3 gas) and treated groups (40 and 60 mu mol/mol), which were exposed for 30, 60,120 and 180 min. After 30 min of O-3 exposure, F. graminearum showed significant growth reduction at both concentrations, complete inhibition occurring after 180 min. With regard to mycotoxins, the DON levels of pericarp and endosperm grain were depleted and after 120 min of exposure, DON was eliminated from both grain portions. Afterward, physical and biochemical analysis showed that there was a significant difference between the carboxyl contents of control and treated wheat starches only after 180 min of O-3 exposure. X-ray diffraction (XRD), lipid peroxidation, total protein profile and scanning electron microscopy (SEM) did not reflect any significant differences after O-3 treatment. The application of O-3 treatment only affected wheat germination after 180 min of exposure, reducing germination capacity by 12.5%. Additionally, there were no changes with respect to the length of the coleoptile or seminal root of germinated wheat seeds. In summary, O-3 gas was effective against fungal growth and caused DON degradation, especially after 120 min at 60 mu mol/mol concentration, without causing physical and biochemical changes in whole wheat grains. (C) 2014 Elsevier Ltd. All rights reserved.