Composition of phenolic compounds in a Portuguese pear (Pyrus communis L. var. S. Bartolomeu) and changes after sun-drying

J Agric Food Chem. 2002 Jul 31;50(16):4537-44. doi: 10.1021/jf020251m.

Abstract

The composition of phenolic compounds of a Portuguese pear cultivar (Pyrus communis L. var. S. Bartolomeu) was determined by HPLC after thioacidolysis. The average concentration of phenolic compounds in pear harvested at commercial maturity stage was 3.7 g per kg of fresh pulp. Procyanidins were the predominant phenolics (96%), with a mean degree of polymerization (mDP) of 13-44; hydroxycinnamic acids (2%), arbutin (0.8%), and catechins (0.7%) were also present. The most abundant monomer in the procyanidin structures was (-)-epicatechin (99%), which was found as extension and terminal units; (+)-catechin (1%) was found only as a terminal unit. Sun-drying of these pears caused a decrease of 64% (on a dry pulp basis) in the total amount of native phenolic compounds. Hydroxycinnamic acids and procyanidins showed the largest decrease; the B2 procyanidin was not found at all in the sun-dried pear. Less affected were arbutin and catechins. In the sun-dried pear, the procyanidins with high mDP became unextractable in the solvents used.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arbutin / analysis
  • Biflavonoids*
  • Catechin / analysis
  • Chromatography, High Pressure Liquid
  • Coumaric Acids / analysis
  • Desiccation*
  • Fruit / chemistry*
  • Phenols / analysis*
  • Polymers / chemistry
  • Proanthocyanidins*
  • Rosaceae / chemistry*
  • Sunlight*

Substances

  • Biflavonoids
  • Coumaric Acids
  • Phenols
  • Polymers
  • Proanthocyanidins
  • procyanidin
  • Catechin
  • Arbutin