2.2.1. Photocatalytic Treatment

The use of UV-visible irradiation combined with a semi-conductive photocatalyst showed high efficiency in the reduction of aflatoxins in a liquid medium [62]. DON was degraded in contaminated wheat samples by 72.8% following the use of photocatalyst UCNP@TiO2 (8 mg mL<sup>−</sup>1) for 90 min with a ratio of wheat to liquid of 1:2 [76].

The photocatalytic efficiency NaYF4:Yb,Tm@TiO2 on the degradation of DON was greater in solution than in wheat. This decrease in efficiency may be caused by the attachment of toxins to starch or proteins in the wheat, or to other wheat components, or even the shielding effect of wheat grains that hinder the light from reaching all contaminated surfaces. A complete degradation was achieved in a solution containing 10 μg mL−<sup>1</sup> of DON when treated with simulated sunlight using NaYF4:Yb,Tm@TiO2 (6 mg mL−1) at pH 7 for 60 min. This rate was decreased to 69.8% when artificially contaminated wheat was treated with UCNPs aqueous solution (Ratio 1:1) by illuminating the samples with a Xe lamp for 120 min [69].


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**Table 2.***Cont.*





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Many factors make the use of these techniques more advantageous. They are completely inorganic and do not result in the formation of secondary metabolites, causing pollution. They are cost-effective and easy to apply, requiring mild conditions [95]. Photocatalysis did not cause significant changes in the starch, the protein contents, or the amino acid value in wheat. However, there are also many disadvantages, such as the increased yellowness and decreased whiteness of the wheat flour, the damaged surfaces of starch granules when a prolonged illumination time is applied, and decreased fatty acid value, wet gluten content, and pasting properties of wheat [76].
