Optimization of the ultrasound-assisted extraction of polyphenols from Aronia and grapes

Food Chem. 2022 Aug 30;386:132703. doi: 10.1016/j.foodchem.2022.132703. Epub 2022 Mar 17.

Abstract

The extraction of phenolics and tannins from cold-hardy grapes is not maximized with the current methods, which lead to unbalanced wines. This study aims to investigate high-power sonication to improve polyphenolic content in cold-hardy grape juice in comparison with chokeberry juice. Three solid to solvent ratios and times were applied on chokeberry and 'Marquette' grape berries using 50% ethanol or 13% acidified ethanol and compared to a conventional extraction technique. Iron-reactive phenolic compounds, tannins content, and color were analyzed during the extractions using UV-Visible spectrophotometry, and anthocyanin content was analyzed using HPLC-DAD. At the 1:2 solid to solvent ratio, the color intensity, phenolics, and tannins content were improved using the ultrasound-assisted extraction on chokeberries. However, the tannin content of 'Marquette' berries remained the same with both techniques and solvents, suggesting that the plant cell wall structure may have a strong impact on the retention of tannins from cold-hardy grapes.

Keywords: Anthocyanins; Aronia melanocarpa; Condensed tannins; High-power sonication; Phenolic compounds; ‘Marquette’ wine grape.

MeSH terms

  • Anthocyanins / analysis
  • Ethanol / analysis
  • Fruit / chemistry
  • Phenols / analysis
  • Photinia* / chemistry
  • Polyphenols / analysis
  • Solvents
  • Tannins / chemistry
  • Vitis* / chemistry
  • Wine* / analysis

Substances

  • Anthocyanins
  • Phenols
  • Polyphenols
  • Solvents
  • Tannins
  • Ethanol