Investigation on the Profile of Phenolic Acids and Flavonoids withAntioxidant Capacity in Florida Highbush (Vaccinium corymbosum L.)and Rabbiteye (Vaccinium virgatum) Blueberries

摘要

It is well documented that blueberry phenolic compositions, such as phenolic acids and flavonoids differ based on species and cultivars. However, phenolic compositions in Florida blueberries have been little explored. Information on Florida blueberries are of interest as they are harvested earlier than other areas of the United States, which may result in compositional differences due to shorter daylight hours and cooler temperatures. Samples were harvested from University of Florida grower-cooperator farm near Gainesville, FL. After liquid-liquid extraction and C-18 SPE cartridge purification, concentrations of phenolic acids and flavonoids of twenty two blueberry cultivars (20 highbush and 2 rabbiteye) were measured using HPLC. Five phenolic acids (gallic acid, protocatechuic acid, chlorogenic acid, caffeic acid and ferulic acid), two flavan-3-ols (catechin and epicatechin) and five flavonols (quercetin-3-galactoside or quercetin-3-glucoside, quercetin-3-arabinoside, myricetin, quercetin and kaempferol) were identified and quantified. Chlorogenic acid was the major component in highbush blueberries. Flavonoid and phenolic acid composition were profoundly different among Florida blueberries and these differences have not been previously reported. The first two components of PCA explained 95% of the variation totally; it showed clear differentiation of blueberry cultivars based on phenolic composition. The majority of the variation between the cultivars was due to variation in quercetin-3-galactoside or glucoside, quercetin-3-arabinoside and chlorogenic acid, which are most likely due to genetic and maturity differences. Complete-linkage clustering analysis displayed five significantly different (p0.05) clusters of blueberries, which were in agreement with PCA results, although some small differences were noted. Furthermore, Florida blueberries can be differentiated based on phenolic composition between highbush and rabbiteye species and varieties. Low flavanol content in rabbiteye blueberries may be related to maturity as these compounds typically decrease as berries ripen. Although the concentrations for phenolic compositions were lower than found in other reports, Florida blueberries contained a greater range of phenolic compounds. This information is valuable for blueberry breeding programs and growers for development of higher phenolic composition cultivar.