Subcritical (carbon dioxide plus ethanol) extraction of polyphenols from apple and peach pomaces, and determination of the antioxidant activities of the extracts


Adil I. H. , Cetin H. I. , Yener M. E. , Bayindirli A.

JOURNAL OF SUPERCRITICAL FLUIDS, vol.43, no.1, pp.55-63, 2007 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 43 Issue: 1
  • Publication Date: 2007
  • Doi Number: 10.1016/j.supflu.2007.04.012
  • Title of Journal : JOURNAL OF SUPERCRITICAL FLUIDS
  • Page Numbers: pp.55-63
  • Keywords: subcritical carbon dioxide extraction, co-solvent, fruit, pomace, phenolic content, antioxidant activity, PRESSURE SOLUBILITY DATA, PHENOLIC-COMPOUNDS, GRAPE SEEDS, NATURAL ANTIOXIDANTS, SUPERCRITICAL CO2, BETA-CAROTENE, VITAMIN-C, ACID, CULTIVARS, OIL

Abstract

The effects of pressure (20-60 MPa), temperature (40-60 degrees C), ethanol concentration (14-20 wt.%) and extraction time (10-40 min) on subcritical (CO(2) + ethanol) extraction of polyphenols from apple and peach pomaces (moisture content congruent to 14%, particle size = 0.638 mm) were determined. All variables increased total phenolic contents (TPC) and antiradical efficiencies (AE) of the extracts significantly (p <= 0.05). The optimum pressure and temperature were 54.6-57 MPa and 55.7-58.4 degrees C for apple pomace, and 50.6-51 MPa and 50.9-52.3 degrees C for peach pomace. The optimum ethanol concentration and extraction time were 20% ethanol and 40 min for both pomaces. TPC of the extracts were 0.47 and 0.26 mg gallic acid equiv./g sample and AE of the extracts were 3.30 and 1.5 mg DPPH(center dot)/mg sample for apple and peach pomaces, respectively. Low TPC and AE of the extracts from peach pomace could be contributed to low concentrations of ferulic and p-coumeric acids, epicatechin, and presence of anthocyanins in peach. (C) 2007 Elsevier B.V. All rights reserved.