US: raspberries top antioxidant list

Raspberries possess much higher antioxidant activity than strawberries, and storage or processing does not remove the valuable compounds, researchers say. In a new study, published in the journal BioFactors, it is reported that raspberries contain almost 50 percent more antioxidant activity that strawberries, three times that of kiwis, and ten times the antioxidant activity of tomatoes.

Breakdown of antioxidants

Vitamin C makes up about 20 percent of the total antioxidant capacity, accounting for up to 30 milligrams per 100 grams of fruit. Anthocyanins, especially cyanidin and pelagonidin glycosides, account for a further 25 percent. Interestingly, the biggest contribution to antioxidant capacity is from ellagitannins, a family of compounds almost exclusive to the raspberry, and are reported to have anti-cancer activity.

“It is especially the presence of large amounts of ellagitannins in raspberry, in combination with the more usual anthocyanins and vitamin C, which makes this fruit an attractive subject of study,” said lead author Jules Beekwilder, from Plant Research International, Wageningen, the Netherlands.

Freezing, storing considered

The researchers noted that freezing and storing of the raspberries did not significantly affect the antioxidant activity of the berries, although the concentration of vitamin C was halved by the freezing process. “Raspberry represents a diverse source of potentially healthy antioxidants and as such can provide a useful component to our daily diet,” concluded the scientists.

Source