Phenolic profiles and metal ions analyses of pulp and peel of fruits and seeds of quince (Cydonia oblonga Mill.).

ABSTRACT

Six hydroxycinnamic acids were identified and determined quantitatively in methanol and acetone extracts from quince peel and pulp, namely 3-O-caffeoylquinic acid (3-CQA), 4-p-coumaroylquinic acid (HC1), 4-O-caffeoylquinic acid (4-CQA), 5-O-caffeoylquinic acid (5-CQA), derivative of p-coumaroylquinic acid (HC2) and 3,5-dicaffeoylquinic acid (3,5-diCQA). The most abundant hydroxycinnamic acid was 5-CQA (neochlorogenic acid) with 259.12-481.4mg/kgf.w. in peel and 97.33-217.36mg/kg in quince pulp. Six flavonols were determined in the extracts from quince, quercetin-3-galactoside (Q-Ga), quercetin-3-rutinoside (Q-Ru), quercetin-3-glucoside (Q-Glu), kaempferol-3-rutinoside (K-Ru), kaempferol-3-glucoside (K-Glu) and derivative of quercetin produced in the reaction between quercetin-glucoside and p-coumaric acid (Q-Glu-p-CouA). Elemental analysis of quince seeds has not been performed previously. Also, using principal component and cluster analyses, we determined a strong negative relationship between total phenols and flavonoids, and Ni and Pb, specifically higher concentrations of these compounds were associated with lower concentrations of these metals.