Preliminary evaluation of Quince (Cydonia oblonga Mill.) fruit as extraction source of antioxidant phytoconstituents for nutraceutical and functional food applications

Background Quince (Cydonia oblonga) fruits can be considered as starting material for the extraction of health-promoting phytochemicals, to be exploited in food and nutraceuticals. In the present work, LC-DAD-MSn analysis allowed to study the phytochemical composition of quince fruits and to compare it with those of six commercial apple varieties. Results Distribution and quantification of secondary metabolites in peel and pulp was studied and compared with six commercial apple varieties. Furthermore the in vitro antioxidant activity was determined by DPPH assay. Quince fruit showed significant amounts of shikimic and quinic acid derivatives, as well as flavonoids and procyanidins. Compared with apple, quince composition is charachterized by the presence of 4-caffeoylshikimic acid, 4-caffeoyl quinic acid, quercetin-3,7-diglucoside, kaempferol-3-O-rhamnoside and kaempferol-7-O-glucoside, while the dihydrochalcones are not detectable. Considering fruit parts,3-O-Caffeoylquinic acid is the most abundant compound both in peels and the pulp. Pearson correlation index indicated a positive relationships between the amount of phenolic constituents and the radical scavenging activity toward DPPH• both for peels and pulps extracts. Conclusions This study highlighted the presence of significant amounts of valuable secondary metabolites in quince and in particular procyanidins and caffeoyl esters with shikimic and quinic acid. Notably, due to the higher content in phenolic compounds and the stronger antioxidant capacity compared to the other considered fruits, the use of C. oblonga as source of antioxidant can be valuable in nutraceuticals , showing new possible applications of quince fruit