Production of antioxidative protein hydrolysates from corn distillers solubles: Process optimization, antioxidant activity evaluation, and peptide analysis

Bioprospects of corn distillers solubles containing a unique thermally treated blend of corn and yeast from ethanol industries were evaluated. This includes alcalase hydrolysis optimization of protein concentrate, measurement of antioxidant activities, and peptide analysis. Response surface methodology (RSM) computed optimum values of enzyme: substrate ratio and incubation time, 5.2% (w/w) and 9.3 h. Besides, artificial neural network proved to be a good predictor of responses (R2 similar to 0.94-0.97) in agreement with RSM. The optimum RSM values maximized antioxidant yield, degree of hydrolysis, DPPH-, hydroxyl-, and superoxide-radical activities. The optimal PH and its three ultrafiltered fractions revealed higher scavenging activities against radicals of DPPH (76.15-85.66%), hydroxyl (81.26-91.91%), and superoxide (35.21-54.06%) at 5.0, 5.0, and 3.0 mg. mL(-1), respectively. The foremost corn (QQPIIGGA, LPPYLSPA, SNIPLSPL, NPILQPY) and yeast (NIIPSPI) peptides were identified. The greater antioxidative characteristics might be due to more hydrophobic amino acids. The results are potent and pave the way forward for alternative valorized product streams in bioethanol industries.