were pooled from five trees. Three replications of five trees were used (three × five = 15 trees in total). Sample extracts were analyzed for their antioxidant activity by ferric-reducing antioxidant power (FRAP) assay ( Benzie and Strain, 1996 ) using
synergistic combinations in a complex mixture of several thousand phytochemicals ( Liu, 2003 ). Berries are known to possess outstanding antioxidative power ( Cho et al., 2004 ; Hannum, 2004 ; Moyer et al., 2002 ). The antioxidant capacity of berries was
sodium hydroxide (NaOH)], and ascorbic acid (mg/100 g fresh weight) by oxalic acid (1%) as described by Koukourikou-Petridou et al. (2007) . In addition, ferric-reducing antioxidant power ( Benzie and Strain, 1996 ) and total phenols ( Singleton et al
) total antioxidant capacity, ( B ) ferrous ion chelating ability (FICA), and ( C ) reducing power 4 weeks after treatment. The values are means of eight replicates ± se . FICA was calculated as the absorbance difference ( A ) between control and sample
was quantified by ferric reducing/antioxidant power (FRAP) assay ( Benzie and Strain, 1999 ), adapted for 96-well plates ( Firuzi et al., 2005 ). Working FRAP solution was freshly made by mixing 15 mL of acetate buffer (300 m m ) and 1.5 mL of 2
-hydroxy-6,7,8,3′,4′,5′-hexamethoxy-flavan-3-ol ( Mashimbye et al., 2006 ), tannins ( Mudau et al., 2007b ), and antioxidants ( Mogotlane et al., 2007 ). Although these secondary metabolites demonstrate their fundamental importance as quality control
; after being shaken well, the absorbance at 517 nm was measured as Ac. DPPH free radical scavenging rate = [1 – (Ai – Aj)/Ac] × 100%. Antioxidant power measurement. The determination of the ferric-reducing antioxidant power was conducted according to
The health status of Alabama's population ranks above the national average with respect to the prevalence of poor overall health indicators. Consumer knowledge of the health benefits of consumption of fresh fruit is lacking. The compositional and nutritional qualities of fruit are highly variable among states with different climate, soil, and other environmental conditions. Compositional and nutritional data of fresh fruit that reflect Alabama growing conditions is limited. Commercially fully ripened kiwi fruit (Actinidia deliciosa cvs. Fitzgerald and Hayward) were compared for fruit quality (pH, TA, °Brix, °Brix/TA, and soluble sugars), and antioxidant properties; Vitamin C (reduced, oxidized, and total), Vitamin C Equivalent Antioxidant Capacity (VCEAC), ferric reducing antioxidant power (FRAP), DPPH radical scavenging activity, total phenolics, and flavonoids. In general, `Fitzgerald' ranked higher in overall fruit quality and antioxidant properties when compared to `Hayward'.
Modified atmosphere (MA) storage of blackberries may maintain quality and increase storage life, but there is limited information about how eastern thornless cultivars respond to MA's. Because there is also a growing interest in the health benefits of antioxidants in blackberries, it would be useful to know how those levels might change during MA storage. In 2002, the eastern thornless blackberry variety Chester was stored in MA; treatments included a control, or initial levels of 20% CO2 or 5% O2. Color, pH, firmness, fresh weight, soluble sugars, titratable acidity, total antioxidant capacity, and the levels of major classes of compounds with antioxidant activity of the fruit were measured at harvest, after 1 week of MA storage at 4 °C, and after 3 additional days at room temperature to simulate common industry practices and grocery display. Total antioxidant capacity was measured using the FRAP (ferric reducing/antioxidant power) assay, and total phenolics and anthocyanins were measured spectrophotometrically. In 2002, soluble sugar levels, fresh weight, titratable acidity, and all classes of antioxidants decreased from day 0 to day 7 to day 10 while the pH increased. Color values did not change. The only trait that differed among treatments was berry firmness; from day 0 to day 7 control fruit was the most firm, and those from the high CO2 treatment were the least firm. Studies were continued in 2003 with the addition of two more eastern thornless blackberry cultivars, Hull Thornless and Triple Crown, and these results will also be presented.
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.