The Inhibitory Effect of Wheat Husks Addition on Aflatoxins Production byAspergillus flavusin Liquid Culture With Various Wheat Compositions as Carbon Sources

Wheat may be infected by the aflatoxigenic moldAspergillus flavusduring pre- and post-harvest activities. Control strategies reported to manage aflatoxin contamination of wheat are expensive and require extensive testing to verify the absence of toxic secondary metabolites or newly formed compounds. The objective of this study was to develop anin vitronew control strategy based on assessing the influence of wheat husks on aflatoxin production byA. flavusin liquid culture. The results showed that aflatoxin production is significantly influenced by the existence of husks in the wheat forms used as carbon substrates according to the following order: full wheat grains < half-crushed wheat grains < wheat flour 82% < wheat flour 72%. By applying a fractional factorial design and a response surface methodology, maximum aflatoxin production (2.567 ng/mg) was predicted when wheat flour 72% (39 g/l) as a carbon source, yeast extract (5 g/l), and a 75-ml medium volume/250 ml flask were utilized. At this optimized condition, after addition of wheat husk extract, the growth and synthesis of aflatoxins ofA. flavuswere repressed by 74.85 and 98.72%, respectively. This finding paves the way to examine the antifungal potential of wheat husk constituents and to compare their efficacy with thyme, cinnamon, sweet basil, and coriander essential oils, which possess antimycotic activities. Accordingly, the wheat husk component SiO(2)showed the highest growth inhibition (67.04%) and reduction ofA. flavusaflatoxins (82.67%). These results are comparable to those obtained from various examined antimycotic essential oils.