Composition of phenolic compounds in a Portuguese pear (Pyrus communis L. var. S. Bartolomeu) and changes after sun-drying.
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.
Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
Dulcineia
D
Ferreira
Sylvain
S
Guyot
Nathalie
N
Marnet
Ivonne
I
Delgadillo
Catherine M G C
CM
Renard
Manuel A
MA
Coimbra
D001104:Arbutin / Q000032:analysis; D044946:Biflavonoids; D002392:Catechin / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D003373:Coumaric Acids / Q000032:analysis; D003890:Desiccation; D005638:Fruit / Q000737:chemistry*; D010636:Phenols / Q000032:analysis*; D011108:Polymers / Q000737:chemistry; D044945:Proanthocyanidins; D027824:Rosaceae / Q000737:chemistry*; D013472:Sunlight
D044946:Biflavonoids; D003373:Coumaric Acids; D010636:Phenols; D011108:Polymers; D044945:Proanthocyanidins; C017674:procyanidin; D002392:Catechin; D001104:Arbutin