Storability and Phenolic Compounds Profile of Organically Grown Blackberries

Fresh market blackberries grown organically in North Carolina were used to determine storage life and phenolic compounds profiles. 'Natchez', 'Ouachita', and 'Navaho' freshly harvested berries were sorted into shiny black (SB) and dull black (DB) ripeness stages and stored at a constant 1 °C for 15 days or at 1 °C for 13 days plus 2 days at 20  °C. Subjective ratings of leakage and decay incidence were lower and overall ratings were higher in SB fruit or berries stored constantly at 1 °C. Freeze dried fruit tissue was extracted with acidified methanol and analyzed using high performance liquid chromatography with photodiode array detector, Synergi 4μ Hydro-RP 80A column (250 X 4.6 mm) and formic acid-methanol gradients. Cyanidin 3-glucoside was the predominant anthocyanin in blackberries, representing 87-96% of the total anthocyanin content, and tended to increase after storage. Other anthocyanins found were pelargonidin 3-glucoside, cyanidin 3-rutinoside, and cyanidin 3-xyloside. Cyanidin 3-xyloside content was the lowest in 'Natchez' (< 0.2%) compared to 'Ouachita' or 'Navaho' (4% to 7%). Gallic acid (7–25 mg/100 g DW in 'Natchez' and 'Navaho') and quercetin 3-galactose or quercetin-3-glucoside contents (6–42 mg/100 g DW in 'Natchez' and 'Navaho') were generally lower in ‘Ouachita’ (6–10  and 5–20 mg/100 g DW for gallic acid and quercetins, respectively), and vanillic acid content was the lowest in ‘Natchez’ (18–24 and 72–87 mg/100 g DW in ‘Natchez’ and 'Ouachita'/'Navaho', respectively). Phenolic contents were generally higher in 'Natchez' and 'Navaho' than in 'Ouachita', and tended to increase during storage. Our results show that organically grown 'Natchez', 'Ouachita', and 'Navaho' blackberries had excellent storage life after 15 days at 1 °C, especially when they were at SB ripeness stage. Organically grown blackberry cultivars used in this study are a rich source of cyanidin 3-glucoside compared to other berries, and phenolic contents did not decrease significantly after storage. Among cultivars, phenolic profile of 'Natchez' was slightly different from that of 'Navaho' or 'Ouachita' in cyanidin 3-xyloside and vanillic acid, but all three cultivars predominate in cyanidin 3-glucoside.