Supercritical and subcritical extraction of ursolic acid and polyphenols from apple pomace: Effect of variables on composition and antioxidant capacity


Elizabeth Ordoñez‐Quintana1 | Ivan Salmeron1 | David Chavez‐Flores1 | Victor Ramos1 | Nestor Gutierrez1 | Lourdes Morales‐Oyervides2 | Efren Delgado3 | Ebenezer Kwofie4 | Michael Ngadi4 | Samuel B. Perez‐Vega1

1 School of Chemical Science, Autonomous University of Chihuahua, Chihuahua, Mexico
2 Chemical Engineering Department, Autonomous University of Coahuila, Saltillo, Mexico
3 Department of Family & Consumer Sciences, New Mexico State University, Las Cruces, NM, USA
4 Bioresource Engineering Department, McGill University, Ste‐Anne‐de‐Bellevue, Quebec, Canada


This research explores the effect of temperature, pressure, static time, dynamic time, co‐solvent, pretreatment, and particle size on the supercritical/subcritical extraction of ursolic acid (UA), polyphenols, and their antioxidant activity. Experiments were controlled by a screen‐out (Plackett–Burman) statistical methodology. From the results, it could be observed that similar conditions benefited the extraction of UA and polyphenols. The highest yield of UA (6,117.2 μg/g) was obtained when ethanol (25% w/w), particle size (>250 μm), and temperature (60°C) were at their high boundaries. Phloridzin and epicatechin were identified as the most abundant polyphenols, showing concentrations of 531.4 and 288.3 μg/g, respectively. A maximum oxygen radical absorbance capacity of 113.5 μmol TE/g and total polyphenolic capacity (TPC) of 1.7 mg GAE/g were obtained. As a result, higher yields were strongly related to the effect of variables on diffusion and solubility, leading to a more efficient and sustainable process.