Antioxidant and cytotoxic properties of nano and fermented-nano powders of wheat and rice by-products

The use of fermentation and nano technology can promote the absorption efficiency and improve the functionality and the added value of cereal by-products. In this study, nano and fermented-nano powders of wheat and rice by-products were prepared by superfine grinding of raw and solid-state fermented materials. Effects of fermentation and superfine grinding on phytochemical, phenolic acids profile, antioxidant and cytotoxic activity were investigated. The results revealed that phenolic contents of fermented-nano wheat bran (FNWB), fermented-nano wheat germ (FNWG) and fermented-nano rice bran (FNRB) increased by 40.5, 59.2 and 27.9%, respectively compared to their raw samples. The free, conjugated and bound forms of most identified phenolic acids apparently increased. Also, the antioxidant activity of nano and fermented-nano forms significantly increased compared to raw materials. The cytotoxic activity of ultrafine ground samples increased compared to raw materials. NRB extract was the most effective treatment with IC50 value of 4.10 mg/mL. These results indicate that superfine grinding and solid state fermentation altered the rigid structure of wheat and rice by-products and increased their bioactivity through increasing the releasable bioactive molecules.