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United States Department of Agriculture

Agricultural Research Service

Title: Oxygen Radical Absorbance Capacity (Orac), Phenolic, and Anthocyanin Concentrations in Fruit and Leaf Tissue of Highbush Blueberry

Authors
item Ehlenfeldt, Mark
item Prior, Ronald

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 4, 2001
Publication Date: N/A

Interpretive Summary: Antioxidants have been shown to have many health benefit properties. Blueberries have been found to be among the highest of common fruits and vegetables in antioxidant levels. To evaluate variation among varieties, antioxidant levels were evaluated in fruit and leaf tissue of 87 highbush blueberry (Vaccinium corymbosum L.) and species-introgressed blueberry (V. x corymbosum L.) cultivars. Leaves were found to have levels of antioxidants approximately 25 times higher than fruit tissue, but further studies would need to be done to determine if leaf tissue could be utilized for health benefits. Leaf antioxidant levels were not correlated with fruit antioxidants, meaning that leaf tissue analysis could not be used during breeding to select for higher fruit antioxidant levels. An analysis of antioxidant values for 11 cultivars versus their parents suggested that antioxidant inheritance is additive (i.e. the average value across a family is the same as the average value of the two parents). Knowledge of antioxidant levels in numerous cultivars will aid breeders in developing new cultivars with higher levels of antioxidants, and will be of value to producers and consumers wishing to take advantage of the higher antioxidant values in some cultivars.

Technical Abstract: Antioxidant capacity as measured by ORAC, total phenolic, and total anthocyanin concentrations were evaluated in fruit tissue of 87 highbush blueberry (Vaccinium corymbosum L.) and species-introgressed blueberry (V. x. corymbosum L.) cultivars. ORAC and phenolic levels were evaluated in leaf tissue of the same materials. Average values for ORAC, phenolics, and anthocyanins in fruit were 15.9 ORAC units (1 unit is 1 micromule Trolox Equivalent), 1.79 mg/g (gallic acid equivalents), and 0.95 mg/g (cyanidin-3-glucoside equivalents), respectively. 'Rubel' had the highest ORAC/gfw values, at 31.1 units, and 'Elliot' had the highest values on the basis of ORAC/cm square surface area. In leaf tissue, values for both ORAC and phenolics were significantly higher than fruit tissue, with mean values of 490.4 ORAC units and 44.80 mg/g (gallic acid equivalents), respectively. Leaf ORAC had a low, but significant correlation with fruit phenolics and anthocyanins, but not with fruit ORAC. An analysis of ORAC values versus calculated midparent values in 11 plants from the 87 cultivar group where all parents were tested suggested that across cultivars, ORAC inheritance is additive. An investigation of ORAC values in a family of 44 'Rubel' x 'Duke' seedlings showed negative epistasis for ORAC values suggesting 'Rubel' may have gene combinations contributing to ORAC which are broken up during hybridization.

Last Modified: 7/22/2014
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