| Abstract
| - From red raspberries, ellagic acid, its 4-arabinoside, its 4‘ (4‘ ‘-acetyl) arabinoside, and its 4‘ (4‘ ‘-acetyl)xyloside, as well as quercetin and kaempferol 3-glucosides, were identified. In addition, twounidentified ellagic acid derivatives were detected. The free radical scavenging activity of the ellagicacid derivatives was evaluated by using the DPPH method and compared to that of Trolox. All ofthe isolated compounds showed antioxidant activity. The effect of processing to obtain jams onraspberry phenolics was evaluated. The flavonol content decreased slightly with processing andmore markedly during storage of the jams. The ellagic acid derivatives, with the exception of ellagicacid itself, remained quite stable with processing and during 6 months of jam storage. The contentof free ellagic acid increased 3-fold during the storage period. The initial content (10 mg/kg of freshweight of raspberries) increased 2-fold with processing, and it continued increasing up to 35 mg/kgafter 1 month of storage of the jam. Then a slight decrease was observed until 6 months of storagehad elapsed. The increase observed in ellagic acid could be explained by a release of ellagic acidfrom ellagitannins with the thermal treatment. Keywords: Raspberry; Rubus idaeus; jams; processing; phenolics; antioxidant activity; ellagic acid;flavonols
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