Antioxidant activity [as measured by oxidation radical
absorbance capacity (ORAC) assay], total anthocyanins, total phenolics, and
quercetin were measured on frozen, fully-mature fruit of 13 and 15 blackberry (Rubus
subgenus Rubus Watson) genotypes in 1999 and 2000, respectively. Additionally,
in 1999, ellagic acid was measured. Eight genotypes were common among sample
years. The highest ORAC value was for 'Kiowa' (67.9 mmol Trolox equivalents/g
of whole fruit) in 2000. Next highest was 'Navaho' which had a two-year average
of 48.8. The lowest activity was for selection APF-12, 17.3. Total anthocyanins
ranged from a high of 3630.9 mg/kg (malvidin-3-glucoside equivalents) for
'Kiowa' in 2000 to 720.6 for APF-12 for the same year. Total soluble phenolics
were highest for APF-12, 10,580.8 mg/kg (chlorogenic acid equivalents) in 2000
to 4217.6 for 'Choctaw' in 1999. Quercetin levels ranged from 94.3 mg/kg fresh
weight for 'Arapaho' in 2000 to 10.2 for '