Wei Yuan, Lijing Zhou, Guangrui Deng, Ping Wang, David Creech and Shiyou Li
Abstract:
Berries of Vaccinium spp. have long been an important source of food and pharmaceutical ingredients and are considered to have high antioxidant potential. Growing blueberries in Texas, United States is a substantial industry, but there is no report on their antioxidant capacity, total phenolics, and anthocyanins. This study evaluates antioxidant capacity and contents of total phenolics and anthocayanins in both fruits and leaves of 19 genotypes including five commercial cultivars and 11 selections of rabbiteye blueberry (V. ashei) and southern highbush (V. corymbosum hybrids), and three native species (V. darrowii, V. arboreum, and V. fuscatum) grown in Nacogdoches, Texas. Significant variations in antioxidant capacity (as measured by FRAP) and contents of total phenolics and anthocyanins in fruit were observed among different species, cultivars or selections with less variation observed among individual plants of the same genotype. Our data from rabbiteye blueberry selections and cultivars support the hypothesis that antioxidant capacity is more highly correlated to total phenolics thanthocyanins. The analysis of five species indicates that antioxidant activity decreased during ripening but total phenolics contents tended to increase with maturity. Antioxidant capacity, total phenolics, and anthocyanin content did not change significantly during storage at 4ºC or -20ºC for two weeks but decreased significantly when berries were oven dried at 65ºC for 48 h. Antioxidant capacity and total phenolics content in leaves of each genotype were 3 to 15 times higher than those in fruits.
Keywords: Blueberry, fruits, leaves, Vaccinium, antioxidant activity, total phenolics, anthocayanins.
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