Physico‐chemical characterization of Cornus kousa Burg. fruit: determining optimal maturity for fresh consumption

Abstract

BACKGROUND: Japanese dogwood (Cornus kousa Burg.) is a popular ornamental plant which develops edible compound fruit utilized in traditional Asian medicine. Previous compositional studies have focused on a small fraction of secondary metabolites at a single maturity stage. In order to address the question of optimal ripeness of Japanese dogwood fruit for consumption the study provides a comprehensive insight into its primary and secondary metabolic profile. RESULTS: The aim of the study was to investigate biochemical composition and morphological traits of Japanese dogwood (Cornus kousa Burg.) fruit at four maturity stages: GF, green fruit; BF, fruit with a defined red blush; RF, ripe fruit; OF, over-ripe fruit. Fruit was characterized by a nearly spherical shape, decreased water content in later stages of ripeness and highest a* values at RF and OF stages. Total sugars increased significantly from GF to OF stage and total organic acids and vitamin C decreased with maturation. Japanese dogwood fruit was characterized by four major phenolic groups: anthocyanins (three), flavonols (eight) hydroxycinnamic acids (three) and flavonoids (one) as well as by four lipophilic antioxidants: tocopherols (two), xanthophylls (five), carotenes (two) and chlorophylls (two). The progression of fruit ripening caused faster accumulation of individual phenolic compounds and lipophilic antioxidants which resulted in significantly higher total phenolic content at the RF and OF stages. CONCLUSION: Japanese dogwood fruit is a rich alternative source of ascorbic acid, ⊍-tocopherol, flavonols and anthocyanins and should be consumed fresh at fully developed red colour of compound berries when their composition is optimal.

An Overview of Traditional Uses, Phytochemical Compositions and Biological Activities of Edible Fruits of European and Asian Cornus Species

“…In this species, high amounts of cyanidin 3-O-glucoside are found, followed by cyanidin 3-O-galactoside and very small quantities of delphinidin 3-O-glucoside [11]. A recent study reported pelargonidin 3-O-galactoside in C. kousa fruits ( [57]).…”

“…Similar to other Cornus species, fruits of C. kousa are characterised by quercetin derivatives (quercetin 3-O-galactoside, quercetin 3-O-xyloside and quercetin 3-O-glucoside) and by kaempferol and myricetin heterosides [57,61,62]. The principal flavonoids and proanthocyanidins found in Cornus fruits are reported in Table 2.…”

“…Ten carotenoids, namely β-carotene, β-carotene-5,6-monoxide, β-cryptoxanthin, lutein, lutein-5,6-epoxide, (9Z, 9 Z)-lutein, (13Z, 13 Z)-lutein, (all-E)-neoxanthin, (9 Z)neoxanthin, luteoxanthin, are reported in the hydroalcoholic extract of C. mas fruits treated with hexane [93]. Six carotenoids, namely lutein, neoxanthin, violaxanthin, antheraxanthin, zeaxanthin, α-carotene, and β-carotene, are found in C. kousa fruits [57].…”

“…Recently, a comprehensive chemical profile of anthocyanins, flavonoids and organic acids was published [57]. Currently, only a few studies have investigated the chemical composition of other Cornus species.…”

“…In C. kousa fruits, triterpenoid acids are numerous, and seven are described (arjunolic, asiatic, 19-hydroxyasiatic, betulinic, corosolic, maslinic, oleanic, pimaric, tormentic, ursolic and 2α-hydroxylursolic acid) [47,87,88]. Five different organic acids (citric, fumaric, oxalic, shikimic and malic acid) and three phenolic acids (chlorogenic, neochlorogenic and 4caffeoylquinic acid) were also identified [57].…”