Impact of supercritical CO2 and traditional solvent extraction systems on the extractability of alkylresorcinols, phenolic profile and their antioxidant activity in wheat bran

Abstract

SC-CO2 and traditional solvent methods were used to extract alkylresorcinols (ARs) in wheat bran (WB) cultivars. WB soluble free, soluble conjugated and bound phenolics were separated by alkaline hydrolysis. Also, the effects of extraction solvents on antioxidant activity were investigated by using three different solvents. The HPLC results showed that the AR content was higher in acetone extracts compared to the SC-CO2. Using ethanol as a co-solvent yielded higher ARs, especially in collector-2 for hard red WB (HRWB) (57.8 mg/100g) and soft red WB (SRWB) (37.8 mg/100g). Ten phenolic acids and six flavonoids were detected in phenolic fractions which ferulic acid was the predominant and mostly found in bound fractions. Two-way ANOVA showed that cultivar, solvent and their interactions had significantly (P < 0.05) different effects on TPC, DPPH, and ORAC values. The best solvents for ORAC, DPPH, and TPC assays were acidified ethanol, 100% acetone, and 50% acetone, respectively.

Keywords

• Alkylresorcinols
• Supercritical carbon dioxide
• ORAC
• Phenolic fractionation
• Extraction solvents