Fate of Phytochemicals during Malting and Fermentation of Type III Tannin Sorghum and Impact on Product Biofunctionality

Abstract

The aim of the present study was to assess the effects of sorghum bioprocessing into Gowéon iron bioavailability and antioxidant properties of the final products. Gowé is an African sour beverage, whose process combines malting and fermenting of sorghum grains. The effects of the durations of germination and fermentation on the phytochemicals were evaluated using a central composite design. The antioxidant capacity and iron bioavailability of the derived flour were also evaluated. During the germination process, the tannin content of the grain decreased from 429.5 to 174.1 mg/100 g DM, while the total phenolic content increased from 300.3 to 371.5 mg GAE/100 g DM. The phenolic acid contents of the flour were significantly modified as a result of the durations of germination and fermentation. Both germination and fermentation enhanced the antioxidant capacity of sorghum flour, and antioxidant characteristics were significantly correlated with the levels of total phenolics, tannins, and phenolic acids. Phytate content of sorghum grain decreased drastically from 1003 to 369.1 mg/100 g DM when the duration of germination or fermentation increased. This was associated with an increase in the bioavailability of iron.