45F-7 |
Antioxidant capacity and phenolic content of bluecrop and ozarkblue blueberries as affected by maturation |
D. PILAND1, L. R. Howard2, M. J. Cho1, and J. R. Clark1. (1) Department of Food Science, University of Arkansas, 2650 N. Young Avenue, Fayetteville, AR 72704, (2) Dept. of Food Science, Univ. of Arkansas, 2650 N. Young Ave., Fayetteville, AR 72701 Blueberries contain high levels of flavonoids, which exhibit potent antioxidant activity as well as numerous other biological and pharmacological properties. Although the effects of genetics, growing season and postharvest storage conditions on phenolic content and antioxidant capacity of blueberries are known, no information is available concerning the effect of maturation on changes in phenolics and antioxidant capacity of blueberry cultivars. The objective of this research was to determine the effect of maturation on phenolic content and oxygen radical absorbing capacity (ORAC) in Bluecrop and Ozarkblue blueberries. Bluecrop (Northern Highbush) and Ozarkblue (Southern Highbush) blueberries were harvested at green, 25, 50, 75 and 100% blue stages of maturity. Fruit were analyzed for hydroxycinnamate, anthocyanin, and flavonol content by HPLC, total phenolics and total anthocyanins using spectrophometric assays and ORAC using a microplate assay. Ozarkblue and Bluecrop blueberries had similar levels of ORAC, total phenolics, total anthocyanins, and hydroxycinnamates over all maturity stages, but Bluecrop had higher levels of flavonols than Ozarkblue. Levels of ORAC, total phenolics and hydroxycinnamates generally decreased from green to 75% blue stages of maturity and then increased from 75% blue to 100% blue stages of maturity. Total anthocyanin content increased from green to the 100% blue stage of maturity, with the largest increase occurring from 75% to 100% blue stages of maturity, while flavonol content decreased from green to the 100% blue stage of maturity. ORAC correlated highly with levels of hydroxycinnamates (r=0.87) and total phenolics (r=0.82) over all maturity stages, while flavonols (r=0.51) and total anthocyanins (r=0.20) exhibited less linear relationships with ORAC. Our results show that phenolic composition and content in blueberries varies according to maturity stage, with green fruit having comparable antioxidant capacity as 100% blue fruit due to exceptionally high hydroxycinnamate content.
Session 45F, Fruit & Vegetable Products: Fruits (Fresh)
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