Over-evaluation of total flavonoids in grape skin extracts containing sulphur dioxide

Food Chem. 2015 Apr 1:172:537-42. doi: 10.1016/j.foodchem.2014.09.125. Epub 2014 Sep 28.

Abstract

Sulphur dioxide (SO2) proved to increase absorbance at 280 nm of grape skin and seed extracts containing it, diluted with ethanol-HCl to assess total flavonoids and anthocyanins in the same analysis. Additional absorbance at 280 nm was also observed in acetone:H2O extracts, if the acetone had not completely evaporated before the extracts were diluted with a solvent. Flavonoids were correctly quantified in the extracts when SO2 or acetone were removed by solid-phase extraction with a C18 RP as sorbent and methanol as eluting solvent.

Keywords: Anthocyanins; Anthocyanins (PubChem CID: 5318979); Flavonoids; Polyphenols; Proanthocyanidins; Proanthocyanidins (PubChem CID: 108065); Sulphur dioxide; Sulphur dioxide (PubChem CID: 1119).

MeSH terms

  • Acetone / chemistry
  • Anthocyanins / analysis
  • Anthocyanins / isolation & purification
  • Flavonoids / analysis*
  • Flavonoids / isolation & purification
  • Phenols / chemistry
  • Phenols / isolation & purification
  • Plant Extracts / chemistry*
  • Seeds / chemistry
  • Seeds / metabolism
  • Solid Phase Extraction
  • Spectrophotometry
  • Sulfur Dioxide / chemistry*
  • Vitis / chemistry*
  • Vitis / metabolism
  • Water / chemistry

Substances

  • Anthocyanins
  • Flavonoids
  • Phenols
  • Plant Extracts
  • Water
  • Sulfur Dioxide
  • Acetone