Polyphenol composition and antioxidant activity in strawberry purees; impact of achene level and storage.

ABSTRACT

In this study the impact of achenes on polyphenolic compounds, ascorbic acids, and antioxidant activities in strawberry purees at production and after storage at 6 and 22 degrees C for 8 and 16 weeks was investigated. Strawberry purees were made from flesh, berry, and achene-enriched homogenate and contained 0, 1.2, and 2.9% achenes, respectively. At production, strawberry purees made from flesh contained more anthocyanins, p-coumaroyl glycosides, and ascorbic acids, whereas increasing achene levels caused increasing levels of ellagic acid derivatives, proanthocyanidins, flavonols, total phenolics (TP), and antioxidant activities. In addition, the anthocyanins, TP, and ferric reducing ability power (FRAP) in purees with more achenes were better retained during storage. Ascorbic acids and anthocyanins declined rapidly during storage, whereas other polyphenols and antioxidant activities were more stable; that is, the contributions from anthocyanins and ascorbic acids to TP and antioxidant activities decreased. The findings that achenes contributed significantly to polyphenol content and stability of strawberry purees may be interesting in a nutritional and, thus, commercial, perspective.