Phytochemical Characterization and Antioxidant Activity of Four Blueberry (Vaccinium sp.) Cultivars from the Southern United States

Blueberries (Vaccinium sp.) are rich in phenolic and anthocyanin compounds that contribute to strong antioxidant activity; however, limited information exists on the biochemical characteristics of Southern United States cultivars. This study evaluated the antioxidant capacity and selected physicochemical properties of four blueberry cultivars (Premier’, ‘Powder Blue’, ‘Brightwell’, and a highbush cultivar) grown in Pine Bluff, Arkansas, USA, except focusing on cultivar-dependent differences. Significant differences were observed among the four blueberry cultivars. Physicochemical analysis showed that ‘Premier’ had the lowest moisture content (78.7%) and the highest pH (3.94), whereas the highbush cultivar showed the highest moisture content (82.20%) and the lowest pH (3.43). ‘Brightwell’ had the highest total soluble solids (TSS) (13 °Brix), while the highbush cultivar showed the lowest TSS (7 °Brix). In terms of antioxidant activity, ‘Powder Blue’ exhibited the strongest activity (IC50 = 20.85 µg/mL), whereas the highbush cultivar showed the weakest activity (42.47 µg/mL). Total phenolics varied markedly among cultivars, with ‘Brightwell’ (3.96 ± 0.08 mg TAE/g DW) and ‘Powder Blue’ (3.56 ± 0.00 mg TAE/g DW) showing the highest levels and the highbush cultivar the lowest (1.81 ± 0.14 mg TAE/g DW). Anthocyanin content was relatively consistent across varieties, ranging from 6.71 to 6.85 A/g fresh weight. Protein quantification using the Lowry method revealed higher protein content in ‘Powder Blue’ (0.080 g/g) compared with the highbush cultivar (0.047 g/g). Sensory evaluation indicated that ‘Premier’ received the highest overall acceptability score (9.5 ± 0.3). This study provides baseline data on antioxidant capacity and key physicochemical properties for these four Southern-adapted blueberry cultivars, supporting their use in the development of functional foods and informing future breeding and production strategies in the region.