Total Phenolic Contents and Antioxidant Potential of Soya Bean and Maize and their Beverages In vitro

The present investigations sought to correlate the total phenolic contents (TPC) with antioxidant potential, using in vitro antioxidant evaluation models, of unprocessed soya bean (SB) and its industrial processed beverages (SBB1 and SBB2) as well as unprocessed maize (SM) and its industrial processed beverages (MBB1 and MBB2). The TPC and antioxidant potential of the samples were measured using standard spectrophotometric methods. The radical scavenging capacity index (SCI50) defined the concentration, in μg/mL, of the sample required to scavenge 50% of the investigated radicals. Likewise, AP50 defined the concentration, in μg/mL, of the sample required to reduce 50% of ferric ion. The TPC of SB, SBB1 and SBB2 was within the range of 0.97 ± 0.02-2.86 ± 0.02 mg gallic acid equivalent per gram dry sample, and TPC of SM, MBB1 and MBB2 were in the increasing order: SM>MBB1>MBB2. The TPC of SB, SBB1 and SBB2 and their corresponding SCI50 against NO–, H2O2 and •−OH gave correlation coefficients between the range: -0.77227-0.338172 units, whereas their corresponding AP50 gave a strong positive correlation. The TPC of SM, MBB1 and MBB2 and their corresponding SCI50 against NO–, H2O2 and •−OH gave correlation coefficients between the range: 0.040672-0.51799 units, whereas their corresponding AP50 showed a strong negative correlation. The study revealed that antioxidant potential was intertwined with the combinatorial antioxidant peculiarities of the various samples.