Impact of cooking and nixtamalization on the bioaccessibility and antioxidant capacity of phenolic compounds from two sorghum varieties

Sorghum (Sorghum bicolor L. Moench) has been sparsely used as human food due to certain anti-nutritional factors such as tannins that reduce its digestibility, although the grain is an important source of bioactive compounds such as phenolic compounds (PCs). This study aimed to assess the impact of cooking and alkaline cooking (nixtamalization) on the bioaccessibility and antioxidant capacity of PCs of two sorghum varieties (white/red). Nixtamalization was the most effective procedure for the reduction of tannins (74.3%). Gallic acid proved to be the most bioaccessible PC (6359 mu g/g). The total phenolics and condensed tannins correlated with the antioxidant capacity (ABTS/DPPH; R-2: 0.30-0.43, p < 0.05). These results confirm the potential of thermal procedures to significantly modify the bioaccessibility of sorghum compounds, enhancing their concentrations and reducing anti-nutritional factors (tannins) while improving their antioxidant capacity.