Quince is a shrub or small tree of the rose family. The common quince ( Cydonia oblonga ) is a tree with edible fruits cultivated from ancient times in Asia and in the Mediterranean area. The quince fruit is similar to that of the related apple and pear but is astringent, and hence it is used chiefly cooked in preserves. Marmalade is said to have first been made from quince.

Quince jam is quite tasty and is a fine addition to more commonly eaten jams.

Quince Research Update
Quince (Cydonia oblonga miller) fruit characterization using principal component analysis.
J Agric Food Chem. 2005 Jan 12;53(1):111-22.
Faculdade de Farmacia, Universidade do Porto, R. Anibal Cunha, 4050-047 Porto, Portugal.
This paper presents a large amount of data on the composition of quince fruit with regard to phenolic compounds, organic acids, and free amino acids. Subsequently, principal component analysis (PCA) is carried out to characterize this fruit. The main purposes of this study were (i) the clarification of the interactions among three factors-quince fruit part, geographical origin of the fruits, and harvesting year-and the phenolic, organic acid, and free amino acid profiles; (ii) the classification of the possible differences; and (iii) the possible correlation among the contents of phenolics, organic acids, and free amino acids in quince fruit. With these aims, quince pulp and peel from nine geographical origins of Portugal, harvested in three consecutive years, for a total of 48 samples, were studied. PCA was performed to assess the relationship among the different components of quince fruit phenolics, organic acids, and free amino acids. Phenolics determination was the most interesting. The difference between pulp and peel phenolic profiles was more apparent during PCA. Two PCs accounted for 81.29% of the total variability, PC1 (74.14%) and PC2 (7.15%). PC1 described the difference between the contents of caffeoylquinic acids (3-O-, 4-O-, and 5-O-caffeoylquinic acids and 3,5-O-dicaffeoylquinic acid) and flavonoids (quercetin 3-galactoside, rutin, kaempferol glycoside, kaempferol 3-glucoside, kaempferol 3-rutinoside, quercetin glycosides acylated with p-coumaric acid, and kaempferol glycosides acylated with p-coumaric acid). PC2 related the content of 4-O-caffeoylquinic acid with the contents of 5-O-caffeoylquinic and 3,5-O-dicaffeoylquinic acids. PCA of phenolic compounds enables a clear distinction between the two parts of the fruit. The data presented herein may serve as a database for the detection of adulteration in quince derivatives. quince fruit quince tree flowering quince.