Search Results

You are looking at 1 - 10 of 49 items for :

  • "oxygen radical absorbance capacity" x
  • All content x
Clear All
Free access

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.

Free access

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.

Free access

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.

Free access

Ann Marie Connor, James J. Luby, and Cindy B.S. Tong

We gratefully acknowledge Willy Kalt and Jane McDonald of Agriculture and Agri-food Canada, Kentville, Nova Scotia, Canada, for cooperation and assistance in performing the oxygen radical absorbance capacity assay.

Free access

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

with an Atago PAL-1 refractometer (Atago U.S.A. Inc., Bellevue, WA) using the same sample prepared for pH measurement. Oxygen radical absorbance capacity. The ORAC assay was performed according to Davalos et al. (2004) with some modifications. Briefly

Free access

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

spectrophotometry at 450 nm using the extinction coefficient for zeaxanthin in methanol. Total carotenoids were expressed as micrograms of zeaxanthin equivalents/100 g FW. Hydrophilic oxygen radical absorbance capacity. Oxygen radical absorbance capacity

Free access

Gary W. Stutte, Sharon Edney, and Tony Skerritt

stainless steel blender until pulverized, then ground into a fine powder using a mortar and pestle. Ground tissue was extracted in acidified methanol (50% v/v), centrifuged, filtered, and stored at –80 °C until analyzed. Oxygen radical absorbance capacity

Free access

Desire Djidonou, Amarat H. Simonne, Karen E. Koch, Jeffrey K. Brecht, and Xin Zhao

, but ORAC values were similar among treatments in 2010. Table 3. Total phenolic content and antioxidant capacity (as assayed by oxygen radical absorbance capacity) in tomato fruit from non- and self-grafted ‘Florida 47’ controls and grafted ‘Florida 47

Free access

Julia M. Harshman, Wayne M. Jurick II, Kim S. Lewers, Shiow Y. Wang, and Christopher S. Walsh

the same plot were bulked across harvest dates for physiochemical analyses because of the amount of berries required. Physiochemical analysis: antioxidant capacity for lipophilic and hydrophilic (oxygen radical absorbance capacity) assay. Five grams of

Free access

David L. Ehret, Brenda Frey, Tom Forge, Tom Helmer, and David R. Bryla

649 656 Byers, P.L. Moore, J.N. 1987 Irrigation scheduling for young highbush blueberry plants in Arkansas HortScience 22 52 54 Ehlenfeldt, M. Prior, R.L. 2001 Oxygen radical absorbance capacity (ORAC) and phenolic and anthocyanin concentrations in