Investigation of the antioxidant potential of black oat, rye and wheat cereals through multi-response extraction optimization with different solvents

Cereals possess functional and nutritional properties already consolidated in the literature; they are also an excellent source of health-promoting bioactive compounds. This work aimed to determine the best solvents to extract phenolic compounds from black oat, rye, and wheat through a simplex centroid design, using pure solvents and binary and ternary mixtures. The response variables were the total phenolic compounds (TPC) and the antioxidants (DPPH, ABTS, FRAP) were quantified. For optimized extract, the phenolic compounds were identified by UHPLC. An optimization study for the recovery of antioxidant compounds from these cereals to obtain extracts with better antioxidant properties is reported. The water and acetone binary mixture extracted 18, 49, and 110% more than water and 3.2, 4.0, and 5.5 times more than TPC acetone for black oat, rye, and wheat, respectively. Chromatography identified that rye has the highest number of phenolic compounds, including vanillic acid (3008.64 μg g-1), ellagic acid 352.05 μg g-1, hesperetin 24.33 μg g-1, and formononetin. To conclude, the binary mixture of water and acetone was the best condition to obtain a maximized extract for the analyses in the optimized proportions of solvents for the extract are as follows: 0.52/0.48 for oats, 0.46/0.54 rye and 0.33/0.67 for wheat, respectively. This study optimizes the time and improves quality in measuring antioxidants, both for cereals and derivatives, and for evaluating the potential of new products.