Phenolic composition and antioxidant activities in flesh and achenes of strawberries (Fragaria ananassa)

Summary

High performance liquid chromatography coupled with diode array and coulometric array detectors were used to characterize and quantify phenolic compounds in achenes and flesh of strawberries (cv Totem and Puget Reliance). Total phenolics and total monomeric anthocyanins were measured and antioxidant activities were evaluated by the FRAP and the ORAC assays. Strawberries contained 1% achenes on a fresh weight basis, however they contributed to c.a. 11% of total phenolics and 14% of antioxidant activities in strawberries. Ellagic acid, ellagic acid glycosides and ellagitannins were the main contributors to the antioxidant activities of achenes. The major anthocyanin in flesh was pelargonidin-3-glucoside, while achenes consisted of nearly equal amounts of cyanidin-3-glucoside and pelargonidin-3-glucoside. Phenolic content and antioxidant activities of strawberry achenes were reduced by industrial processing. However, the levels were still high and strawberry waste by-product could thus be a possible source of nutraceuticals or natural antioxidants.