title: Antioxidants in raspberry: on-line analysis links antioxidant activity to a diversity of individual metabolites.
abstract: The presence of antioxidant compounds can be considered as a quality parameter for edible fruit. In this paper, we studied the antioxidant compounds in raspberry (Rubus idaeus) fruits by high-performance liquid chromatography (HPLC) coupled to an on-line postcolumn antioxidant detection system. Both developmental and genetic factors were assessed by comparing fruits from a single cultivar of different ripening stages and by comparing ripe fruits of 14 raspberry cultivars, respectively. The HPLC-separated antioxidant compounds were identified using HPLC-photodiode array coupled to mass spectrometry (quadrupole time-of-flight tandem mass spectrometry), using a reference lock mass for determining accurate masses. The dominant antioxidants could be classified as anthocyanins, ellagitannins, and proanthocyanidin-like tannins. During fruit ripening, some anthocyanins were newly produced, while others, like cyanidin-3-glucoside, were already present early in fruit development. The level of tannins, both ellagitannins and proanthocyanidin-like tannins, was reduced strongly during fruit ripening. Among the 14 cultivars, major differences (>20-fold) were observed in the levels of pelagonidin type anthocyanins and some proanthocyanidin type tannins. The content of ellagitannins varied approximately 3-fold. The findings presented here suggest that the content of individual health-promoting compounds varies significantly in raspberry, due to both developmental and genetic factors. This information will assist in the future development and identification of raspberry lines with enhanced health-promoting properties.
authors.affiliation: Plant Research International, Postbus 16, 6700 AA Wageningen, The Netherlands. Jules.Beekwilder@wur.nl
authors.forename: Jules
authors.initials: J
authors.lastname: Beekwilder
authors.forename: Harry
authors.initials: H
authors.lastname: Jonker
authors.forename: Patrick
authors.initials: P
authors.lastname: Meesters
authors.forename: Robert D
authors.initials: RD
authors.lastname: Hall
authors.forename: Ingrid M
authors.initials: IM
authors.lastname: van der Meer
authors.forename: C H
authors.initials: CH
authors.lastname: Ric de Vos
mesh_terms: D000872:Anthocyanins / Q000032:analysis; D000975:Antioxidants / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005638:Fruit / Q000737:chemistry* / Q000254:growth & development; D013058:Mass Spectrometry; D027824:Rosaceae / Q000737:chemistry* / Q000235:genetics / Q000254:growth & development; D013045:Species Specificity; D021241:Spectrometry, Mass, Electrospray Ionization; D013053:Spectrophotometry; D013634:Tannins / Q000032:analysis
chemical_list: D000872:Anthocyanins; D000975:Antioxidants; D013634:Tannins