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, liquid chromatography coupled with diode array detection and tandem mass spectrometry analysis allowed the study of the phytochemical composition of quince fruits and to compare it with those of six commercial apple varieties. RESULTS The distribution and quantification of secondary metabolites in peel and pulp were studied and compared with six commercial apple varieties. Furthermore the in vitro antioxidant activity was determined by 2,2-diphenyl-2-picrylhydrazyl (DPPH) assay. Quince fruit presented significant amounts of shikimic and quinic acid derivatives, as well as flavonoids and procyanidins. Compared with apple, quince fruit composition was characterized by the presence of 4-caffeoylshikimic acid, 4-caffeoyl quinic acid, quercetin-3,7-diglucoside, kaempferol-3-O-rhamnoside and kaempferol-7-O-glucoside, and the dihydrochalcones were not detectable. The peel showed the highest contents of phenolics, whereas 3-O-caffeoylquinic acid was the most abundant compound in the quince pulp. The Pearson correlation index was calculated considering the quantitative amount of the phenolic constituents and the radical scavenging activity toward DPPH center dot both for peel and pulp extracts. CONCLUSIONS This study highlighted the presence of significant amounts of valuable secondary metabolites in quince fruit, in particular the procyanidins and caffeoyl esters with shikimic and quinic acid. Notably, owing to the higher content in phenolic compounds and the stronger antioxidant capacity compared with the other fruits considered, the use of C. oblonga as a source of antioxidant can be valuable in nutraceuticals, revealing new possible applications of quince fruit. (c) 2018 Society of Chemical Industry