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Brenner L. Freeman, Janet C. Stocks, Dennis L. Eggett, and Tory L. Parker

measured on the first two pickings of fresh berries for general comparison with literature values. ORAC and total phenolic analyses were performed on the fresh, refrigerated, and frozen berries from all pickings. Refrigerated and frozen berries were allowed

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Charles R. Brown, David Culley, Meredith Bonierbale, and Walter Amorós

(ORAC) is a measure of the capacity of an antioxidant to delay the oxidation of a target molecule. ORAC is measured as the decay of fluorescence of a certain fluorogen in the presence of a radical-generating compound and antioxidants. The assay is

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Valtcho D. Zheljazkov, Santosh Shiwakoti, Tess Astatkie, Ivan Salamon, Daniela Grul'ová, Silvia Mudrencekova, and Vicki Schlegel

of all cumin oil samples collected in this study (in 3 replicates + 3 internal replicates = 9 total replications per sample) was analyzed using the ORAC oil method ( Huang et al., 2002a , 2002b ). Specific details regarding this method were

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Mark Ehlenfeldt and Ronald L. Prior

Antioxidant capacity as measured by ORAC, total phenolic, and total anthocyanin concentrations were evaluated in leaf tissue of the same 86 highbush blueberry cultivars, and ORAC and phenolic levels evaluated in leaf tissue of the same materials. Average values for ORAC, phenolics, and anthocyanins in fruit were 15.9 ORAC units (1 unit = 1 μmol Trolox Equivalent), 1.79 mg/g (gallic acid equivalents), and 0.95 mg/g (cyanidin-3-glucoside equivalents), respectively. `Rubel' had the highest ORAC values, at 31.1 units. Values for ORAC and phenolics in leaf tissue were significantly higher than fruit tissue, with mean values of 490.4 ORAC units and 44.8 mg/g in leaf tissue, respectively. No significant correlations were found between fruit ORAC and leaf ORAC, or between fruit ORAC and leaf phenolics. Investigation of ORAC values in a family of 44 `Rubel' × `Duke' seedlings showed negative epistatis for ORAC values. However, an analysis of ORAC values vs. pedigree in plants from the 86 cultivar groups suggested that, across cultivars, ORAC inheritance in generally additive.

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Mark K. Ehlenfeldt and Ronald L. Prior

Antioxidant capacity as measured by ORAC, total phenolic, and total anthocyanin concentrations were evaluated in fruit tissue of 86 highbush blueberry cultivars, and ORAC and phenolic levels evaluated in leaf tissue of the same materials. Average values for ORAC, phenolics, and anthocyanins in fruit were 15.9 ORAC units (1 unit = 1 micromole Trolox Equivalent), 1.79 mg·g–1 (gallic acid equivalents), and 0.95 mg·g–1 (cyanidin-3-glucoside equivalents), respectively. ëRubel' had the highest ORAC values, at 31.1 units. Values for ORAC and phenolics in leaf tissue were significantly higher than fruit tissue, with mean values of 490.4 ORAC units and 44.8 mg·g–1 in leaf tissue, respectively. No significant correlations were found between fruit ORAC and leaf ORAC, or between fruit ORAC and leaf phenolics. Investigation of ORAC values in a family of 44 `Rubel' × `Duke' seedlings showed negative epistasis for ORAC values. However, an analysis of ORAC values vs. pedigree in plants from the 86 cultivar groups suggested that across cultivars, ORAC inheritance is generally additive.

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Jennifer L. Waters and Stephen R. King

Carotenoids are important phytochemical components of our diet and have gained recent attention as important nutritive compounds found mainly in fruits and vegetables with red, orange, and yellow hues. Lycopene is often cited as being inversely correlated with the occurrence of various cancers, in lowering rates of cardiovascular disease, and improving other various other immune responses. Antioxidant activity, specifically oxidative radical quenching power, is the putative rationale for carotenoids' involvement in disease risk reduction. It is unlikely, however, that carotenoid content and antioxidant capacity are directly correlated in the whole food since there are other antioxidants present in watermelon, such as various free amino acids. A total measure of antioxidant potential may prove to be a useful tool for measuring watermelon nutritional value and implementing pursuant breeding goals. One assay that has gained recent popularity is the oxygen radical absorbance capacity (ORAC) assay. ORAC includes two assays that separate lipophylic and hydrophilic antioxidants. Currently, most ORAC protocols use isolated compounds or freeze-dried fruit or vegetable samples. Here, the application of a standard hexane-type extraction method, which is more amenable to whole food carotenoid-containing samples, was investigated as a candidate extraction method for the ORAC assay. Variants of this method as well as of the standard ORAC extraction were compared for extraction efficiency. Finally, ORAC values were correlated with carotenoid content and shown to hold a loose negative correlation. Possible reasons for this are considered and discussed.

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Gary W. Stutte, Sharon Edney, and Tony Skerritt

analysis. Plant extracts were analyzed for antioxidant potential using the oxygen radical absorbance capacity (ORAC) assay as described by Ou et al. (2001) using a Tecan GENios Pro plate reader (Tecan, Salzburg, Austria) equipped with a dual injection

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Wilhelmina Kalt, Christopher Lawand, Daniel A.J. Ryan, Jane E. McDonald, Horst Donner, and Charles F. Forney

The antioxidant properties of blueberries have been examined only in ripe fruit, although fruit of different maturities are used in processed food products. In this study, highbush blueberry cultivars Bergitta, Bluegold, and Nelson highbush blueberry fruit at different stages of ripeness were examined to characterize differences in oxygen radical absorbing capacity (ORAC) and the phenolic components responsible for ORAC. Underripe fruit at different stages of maturity were also stored at 20 °C for up to 8 days to assess changes in ORAC and phenolic content. Anthocyanin content was substantially higher in fruit of more advanced stages of ripeness. In contrast, the phenolic content and ORAC were lower in the riper fruit. Anthocyanins continued to form during storage, although rate of pigment formation declined after about 4 days. Less anthocyanin pigment was formed in the less ripe fruit. After 8 days of storage, the anthocyanin content of fruit harvested 5% to 50% or 50% to 95% blue exceeded that of ripe fruit. Up to 60% of the total phenolic content could be accounted for by anthocyanins. ORAC was positively correlated with total phenolic content (R 2 = 0.78), but not with anthocyanin content.

Open access

Ruixiang Yan, Joshua B. Gurtler, James P. Mattheis, and Xuetong Fan

ultraviolet-C as described earlier, fruit were stored at 20 °C for 7 d. Color, firmness, and oxygen radical reducing capacity (ORAC) were measured on 0, 1, 4, and 7 d after treatment. There were six fruits for each replicate and four replicates (a total of 24

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C.R. Brown, D. Culley, C.-P. Yang, R. Durst, and R. Wrolstad

A breeding effort designed to increase the antioxidant level of potato (Solanum tuberosum L.) by means of high concentrations of anthocyanins and/or carotenoids provided selected materials for analysis. Extraction methods suitable for isolating both hydrophilic and lipophilic compounds were used and measurements of total anthocyanin and total carotenoid were made. Two methods of measurement of oxygen radical absorbance capacity (ORAC) adapted to hydrophilic and lipophilic compounds were applied. Total anthocyanin values varied between 9.5 and 38 mg per 100 g fresh weight (FW). The hydrophilic fraction ORAC measurements among anthocyanin-rich clones varied between 250 and 1420 μmol Trolox equivalents per 100 g FW. These two variables were significantly correlated, r = 0.73, and with significant positive slope in linear regression. Measurement of total carotenoids revealed differing degrees of yellowness covered a range of total carotenoid extending from 35 to 795 μg per 100 g FW. Dark yellow cultivars had roughly 10 times more total carotenoid than white-flesh cultivars. The lipophilic fraction ORAC values ranged from 4.6 to 15.3 nmoles α-tocopherol equivalents per 100 g FW. Total carotenoid was correlated with the lipophilic ORAC values, r = 0.77, and also had a statistically significant positive regression coefficient. Clones with red and yellow pigments visible in the flesh had anthocyanins and carotenoids in elevated levels and ORAC contributions from both fractions. The introgression of high levels of carotenoid from germplasm directly extracted from the Papa Amarilla (yellow potato) category of cultivars of South America into long-day adapted North American materials is presented here. Although anthocyanins and carotenoids are major contributors to antioxidant activity, other constituents of potato flesh likely play significant roles in total antioxidant values.