title: High contents of nonextractable polyphenols in fruits suggest that polyphenol contents of plant foods have been underestimated.
abstract: The content of polyphenols in fruits reported in the literature normally refers to extractable polyphenols (EPP) analyzed in aqueous-organic extracts. However, significant amounts of bioactive compounds that are usually not considered in nutritional studies remain in the residue from extraction as nonextractable polyphenols (NEPP). The main objective of this work was to analyze both EPP and NEPP (hydrolyzable polyphenols and proanthocyanidins). EPP were analyzed in methanol/acetone/water extracts, and NEPP were determined in acidic hydrolysates of extraction residue from apple, peach, and nectarine using HPLC-MS and spectrophotometry. Results showed that the NEPP content (112-126 mg/100 g of fresh fruit) was higher than the EPP content (18.8-28 mg/100 g of fresh fruit). Further analyses of NEPP in other fruits and plant foods consumed in diets are needed to compile a complete database of use for nutritional and biological studies.
authors.affiliation: Department of Metabolism and Nutrition, ICTAN, CSIC, Jose Antonio Novais 10, Madrid, Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: Arranz
authors.forename: Fulgencio
authors.initials: F
authors.lastname: Saura-Calixto
authors.forename: Shika
authors.initials: S
authors.lastname: Shaha
authors.forename: Paul A
authors.initials: PA
authors.lastname: Kroon
mesh_terms: D005419:Flavonoids / Q000032:analysis* / Q000302:isolation & purification; D005638:Fruit / Q000737:chemistry*; D010636:Phenols / Q000032:analysis* / Q000302:isolation & purification; D010936:Plant Extracts / Q000032:analysis* / Q000302:isolation & purification; D010945:Plants, Edible / Q000737:chemistry*; D059808:Polyphenols
chemical_list: D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols