Influence of supercritical fluid extraction parameters in preparation of black chokeberry extracts on total phenolic content and cellular viability

Black chokeberries (Aronia melanocarpa), deciduous shrubs of the Rosaceae family, are native to northeastern North America. Chokeberry fruits are cultivated to make jellies, juices, and wines. Black chokeberry pulp is rich in phenolics and other antioxidants and exhibits potential for health and food packaging benefits. Chokeberries' in vitro antioxidant activity is among the highest values of all berries, though chokeberry extraction techniques frequently employ environmentally unfavorable solvents or are time-inefficient. Batch extraction of antioxidants from chokeberry pomace using supercritical carbon dioxide with an ethanol modifier was used to examine the effects of plant loading, pressure, temperature, and percent ethanol by weight. Effects on total phenolic content (TPC) and the optimal conditions for extractions within these ranges are reported. Multivariate analyses reveal the following relationships of extraction conditions upon TPC: Temperature is directly proportional, percent ethanol by weight is inversely proportional, and chokeberry loads can be increased to enhance antioxidant activity, though not through a linear relationship. In studies involving 0.5 g plant load, the conditions 24.9MPa, 68°C, 90wt-% CO_2, and 10wt-% ethanol generated the highest TPC value, 3.42 ± 0.20 mg gallic acid equivalents/gram chokeberry. Chokeberry extracts displayed antiproliferative effects on the SKBr3 breast cancer line and the 52KO MEF line, although TPC was not predictive of cellular responses. HPLC-MS data suggest cyanidin hexose and cyanidin pentose compounds as well as quercetin deoxyhexose-hexose as components of the more favorable extraction product that reflected a significant decrease in viability for the extract in comparison with ethanol control in the SKBr3 breast cancer line.