The effect of soaking of white and red varieties of Sorghum bicolor flour on its antioxidant, antidiabetic and physicochemical properties

Sorghum is rich in beneficial phytochemicals such as phenolic acids, anthocyanins, phytosterols, tannins, and policosanols. This study aimed to study comprehensively the antioxidant and antidiabetic activities of red and white sorghum compared to soaked sorghum. The treatment process of soaked sorghum was carried out by soaking white and red sorghum grains for 2 h at 50 ℃ followed by drying in the sun for 8 h. All the sorghum grains were processed into flour. The antioxidant assay by DPPH showed that red sorgum flour (RSF) had the highest antioxidant activity with IC50 of 98.85 ppm, followed by soaked red sorgum flour (RSF2), white sorghum flour (WSF) and soaked white sorghum flour (WSF2). Meanwhile, for the antidiabetic assay, WSF and RSF had similar alpha-glucosidase inhibitory activity as of 97.43% and 97.42%, respectively at concentrations of 1000 ppm. Total phenolic assay using Folin-Ciocalteau reagent showed that RSF2 had the highest content as of 5031.6 mg GAE/g. The physico-chemical properties of sorghum flour were also studied by proximate analysis, SEM (Scanning electron microscopy), FTIR (Fourier transform infrared spectroscopy), XRD (X-ray diffraction), and XRF (X-ray fluorescence spectroscopy).The result showed that sorghum flour had good potential properties as flour substitution in functional food products since its good antioxidants and antidiabetic properties.