The anthocyanin composition was analysed in strawberry fruits from five different cultivars (cv. Eris, Oso Grande, Carisma, Tudnew and Camarosa). Twenty-five defined anthocyanin pigments were detected, most of them containing Pelargonidin (Pg) as aglycone; some cyanidin (Cy) derivatives were also found. Glucose and rutinose were the usual substituting sugars, although arabinose and rhamnose were also tentatively identified; some minor anthocyanins showed acylation with aliphatic acids. A relevant aspect was the detection of anthocyanin-derived pigments, namely 5-carboxypyranopelargonidin-3-glucoside and four condensed pigments containing C-C linked anthocyanin (Pg) and flavanol (catechin and afzelechin) residues. Total anthocyanin content ranged between 200 and 600 mg kg À1 , with Pg 3-gluc constituting 77-90% of the anthocyanins in the strawberry extracts followed by Pg 3-rut (6-11%) and Cy 3-gluc (3-10%). A notable variability was found among the anthocyanin concentrations in samples of a same variety and harvest, indicating a strongly influence of the degree of maturity, edaphic-climatic factors and post-harvest storage.

New high performance liquid chromatography (HPLC) conditions were developed for the separation of strawberry anthocyanins that provided a good resolution of peaks at a low flow rate compatible with the requirements of the mass spectrometry (MS) detector. A strawberry extract was fractionated by column chromatography and simple fractions containing basically anthocyanins were obtained, making their analysis by HPLC possible using on-line photodiode array detection and MS. Information on the identity of the major and some secondary anthocyanins in strawberry was obtained from their retention characteristics, UV-visible spectra and mass spectra. The presence in strawberry of the previously reported cyanidin 3-glucoside, pelargonidin 3-glucoside, pelargonidin 3-rutinoside and pelargonidin 3-acetylglucoside was confirmed and cyanidin 3-rutinoside was identified in strawberry for the first time. Furthermore, cyanidin 3-malonyldiglucoside, pelargonidin 3-malylglucoside, a pelargonidin bioside and two possible pelargonidin 3-biosides acylated with acetic acid were also tentatively assigned.

Pigments resulting from the direct condensation of anthocyanins and flavanols are usually associated with reactions taking place during processing and storage of plant-derived foods and beverages and have been particularly studied in aged red wines. In this paper, small amounts of flavanol-anthocyanin condensed pigments are found in different plant extracts. Structures are suggested for 10 such condensed pigments detected in extracts of strawberry, runner beans, purple corn and grape skins, based on their MS n fragmentation patterns, following analyses by electrospray tandem mass spectrometry. All of them correspond to dimers containing a flavan-3-ol [either (epi)afzelechin, (epi)catechin or (epi)gallocatechin] as the upper unit carbon-carbon linked to a lower anthocyanin unit consisting of different delphinidin, cyanidin, pelargonidin, peonidin or malvidin derivatives. The detection of these pigments in plant extracts may suggest that they are natural pigments and not products exclusively formed during storage and ageing of processed foods and beverages, as was previously assumed.

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