Free Radical Scavenging Activity and Phenolic Content in Strawberry Fruit and Jam

Fresh fruit of three strawberry cultivars Fragaria ananassa × Duch. (cvs. ‘Clery’, ‘Honeoye’ and ‘NF 421’ (Asia)) were investigated and used to produce jams, which were analyzed before and aft er dark storage at 20 °C for six months. Th e aim of this investigation was to characterize all the samples in relation to the total phenolics, fl avonoids, nonfl avonoids, total anthocyanins and antioxidant activity. Among investigated strawberry fruit cv. Clery showed the highest amount of total phenolics, while regarding to total anthocyanins, cvs. ‘Honeoye’ and ‘NF 421’ showed higher amounts of total anthocyanins. Th e jam processing under applied conditions had appreciable eff ects on preserving stability of polyphenolics. Our results showed that total phenolics were more stable during processing in comparison with total anthocyanins. Furthermore, in all investigated samples fl avonoids were predominant. Relevant diff erences among cultivars were observed when total phenolics, total anthocyanins, fl avonoid and nonfl avonoid contents in jams were compared. Aft er six months storage, in all investigated samples anthocyanins were at least stable, without marked infl uences of cultivar. Compared to the strawberry fruits, the jams also represented a signifi cant source of antioxidant compounds, even considering the lower content of phenolic compounds. Six month storage had infl uence on further decrease of antioxidant activity. Among investigated samples, the highest correlation was found in the total anthocyanins contents and the DPPH. Hence, the obtained results showed that besides fresh strawberry fruit, the strawberry jams also possess noticeable content of important bioactive compounds with considerable antioxidant activity.