Extraction and fractionation of alkylresorcinols from triticale bran by two-step supercritical carbon dioxide

Bran from triticale cultivars Ultima and Pronghorn and Canadian Prairie Spring (CPS) wheat were fractionated using a two-step sequential supercritical carbon dioxide (SC–CO2) extraction technique with and without ethanol to selectively extract and enrich high-value alkylresorcinols (ARs). Pure SC–CO2 (70 °C; flow rate 25 g/min; pressure 35 MPa), was used for the first extraction step. The non-polar lipids yield ranged from 3.08 to 3.26 g/100 g and they were composed mainly of C18:2 (33–41 g/100 g), C18:1 (15–21 g/100 g), C16:0 (15–19 g/100 g), and C18:3 (4–5 g/100 g) fatty acids. The second extraction step, performed on the bran remaining after the first extraction, was carried out with SC–CO2 plus 0.5 mL/min ethanol (70 °C; flow rate 5 g/min; pressure 35 MPa). The resulting total polar lipid yield of bran samples ranged between 0.62 and 0.86 g/100 g and the main compounds present in the polar lipids were ARs. The total AR contents of triticale cv Ultima, wheat, and triticale cv Pronghorn were 70, 68 and 36 mg/100 g, respectively. Saturated and unsaturated AR homologues of C15:0, C17:0, C19:0, C19:1, C21:0, C21:1, C23:0 and C25:0 were detected in all samples. Over 98% of the triticale ARs and over 95% of the wheat ARs were extracted under the SC–CO2 conditions used.