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Abstract
This study offers a systematic characterization of the phenolic constituents in twoGeorgia-grown fruit species, and provides a better understanding of their antioxidative properties from both chemical and biological perspectives. Two representative fruit types, peaches and blackberries, were investigated due to their commercial and economic importance to the Georgias agricultural sector. The research employed the chromatographic techniques of Sephadex LH-20 column chromatography and HPLC-MS to give a detailed characterization of the fruits phenolic profiles both qualitatively and quantitatively. A number of new phenolic compounds in the extracts analyzed were elucidated by this study, some for the first time. The phenolic profiles also vary depending on various intrinsic and extrinsic factors including cultivar choice, geographic location, and time of harvest. Six Georgia-grown peach varieties were studied and cultivar-based differences were observed in terms of phenolic concentrations and antioxidant activities, with those requiring a longer period before harvest exhibiting greater antioxidant capacities. Two cultivars showing contrasting antioxidant capacities based on in vitro chemical assays, also exhibited a significant difference when the analysis was conducted on the basis of fresh weight in the two biological assays, namely cellular antioxidant activity (CAA) and anti-glycation assays. Procyanidins isolated from the extracts exhibited remarkable antioxidant capacity relative to the other phenolic classes present according to both chemical and biological assays. The U.S. Southeastern erect-type blackberry cultivars, released by the University of Arkansas breeding program, were found to possess a different total phenolics content and composition from those of Northwestern cultivars. Propelargonidin B-type dimer and ellagitannins were the dominant phenolics in these Georgia-grown berries, and appear to be responsible for significant antioxidant activity.