Dietary antioxidants may have a role in preventing some of the chronic diseases in humans resulting from free radical oxidation of lipids and other cellular components. Blueberries (Vaccinium L. sp.) are considered one of the best fresh fruit sources of antioxidants, and there is the potential to increase the antioxidant activity further through breeding. Thus, the variability of fruit antioxidant activity (AA) was examined among a set of 16 highbush and interspecific hybrid cultivars grown at locations in Minnesota (MN), Michigan (MI), and Oregon (OR) over 2 years (1998 and 1999) to determine effects of genotype, year, and location. Nine cultivars were common to all three locations in both years. Antioxidant activity, total phenolic content (TPH), and total anthocyanin content (ACY), were determined in triplicate samples from each genotype. Cultivars differed significantly (P ≤ 0.05) in AA, TPH, and ACY both within and over locations. The single location mean AA for all cultivars changed significantly between the 2 years in OR and in MI, while the single location mean for TPH differed between the 2 years in MN and MI. Changes in cultivar rank were significant for AA, TPH, and ACY between years within each location. Significant changes in rank for TPH and ACY were also noted between pairs of locations as well. Pearson's correlation for AA (based on cultivar means) appeared highest between MN and OR (r = 0.90) and MN and MI (r = 0.69) in 1998; correlations between locations for the combined years were 0.74 for MN and OR, 0.55 for MN and MI and 0.45 for MI and OR. For the group of nine cultivars, AA correlated well with TPH within each location, with r ranging from 0.67 to 0.95 for data from individual and combined years. Correlation of AA with ACY at each location was lower than that for AA with TPH, in both individual and combined years. This study demonstrates significant genotype× environment interaction for AA in blueberry.
Ann Marie Connor, James J. Luby, Cindy B.S. Tong, Chad E. Finn and James F. Hancock
James D. Spiers, Fred T. Davies, Scott A. Finlayson, Chuanjiu He, Kevin M. Heinz and Terri W. Starman
This research focused on the effects of nitrogen fertilization on jasmonic acid accumulation and total phenolic concentrations in gerbera. The phytohormone jasmonic acid is known to regulate many plant responses, including inducible defenses against insect herbivory. Phenolics are constitutive secondary metabolites that have been shown to negatively affect insect feeding. Gerbera jamesonii `Festival Salmon Rose' plants were grown in a growth chamber and subjected to either low fertilization (only supplied with initial fertilizer charge present in professional growing media) or high fertilization (recommended rate = 200 mg·L-1 N). Plants were fertilized with 200 mL of a 15N–7P–14K fertilizer at 0 or 200 mg·L-1 N at each watering (as needed). Treatments consisted of ±mechanical wounding with a hemostat to one physiologically mature leaf and the subsequent harvest of that leaf at specified time intervals for jasmonic acid quantification. Total phenolics were measured in physiologically mature and young leaves harvested 0 and 10 hours after ±mechanical wounding. Low-fertility plants had reduced aboveground dry mass, were deficient in nitrogen and phosphorus, and had about a 10× higher concentration of total phenolics when compared to high fertility plants. In low-fertility plants, young leaves had greater concentrations of phenolics compared to physiologically mature leaves. There were no differences in total phenolics due to wounding. The effect of nitrogen fertilization on jasmonic acid accumulation will also be discussed.
Ann Marie Connor, M. Joseph Stephens, Harvey K. Hall and Peter A. Alspach
Variance components and narrow-sense heritabilities were estimated for antioxidant activity (AA), total phenolic content (TPH), and fruit weight in red raspberry (Rubus idaeus L.) fruit from offspring of a factorial mating design. Forty-two full-sib families utilizing seven female and six male parents were evaluated in each of two years in Motueka, New Zealand. In a single year, values within individual half-sib families ranged as widely as 25.3-79.4 μg·g-1 fruit for AA, 205-597 mg/100 g fruit for TPH, and 1.06-7.69 g for fruit weight. Analyses of variance for these three variates demonstrated significant parental source variation in both individual and combined year analyses. For AA and TPH, female parental effects accounted for ≈7% to 19% of total variation, while male effects accounted for ≈6% to 8%. A partially pigment deficient R. parvifolius L. derivative female parent accounted for some of these differences. Female × male parent interaction was not significant for AA and TPH and was marginally significant for fruit weight in combined year analysis. Year had a significant effect on the overall mean AA and TPH, but contributed less than genetic effects to the overall variation in all three traits. Interactions of year with genetic effects were not statistically significant for AA or TPH, indicating that between-year rank or scale changes among families were negligible. The largest proportion of variation was found within rather than among full-sib families. However, variation among plots within full-sib families accounted for 12% to 19% of total variation, indicating environmental differences accounted for some of the observed within-family variation in AA and TPH. Antioxidant activity and TPH were highly phenotypically correlated (r = 0.93); their genetic correlation (r = 0.59) implies that substantial additive genetic factors underlie the phenotypic correlation, but that nonadditive genetic or environmental influences are also important. Both AA and TPH were weakly negatively phenotypically correlated with fruit weight (r = -0.34 and -0.33, respectively), but the corresponding genetic correlations were close to zero. Thus, selection for both high AA or TPH and high fruit weight is possible. Narrow-sense heritability estimates based on variance components from combined year data were h 2 = 0.54, 0.48, and 0.77 for AA, TPH, and fruit weight, respectively. These estimates imply a rapid response to selection is possible.
Daniel A. Stanley and Donald J. Huber
In previous studies, 1-methylcyclopropene (1-MCP) was shown to significantly suppress peel degreening and appearance of senescent spotting of banana fruit (Stanley and Huber, 2004). In the present study, the effect of the ethylene antagonist on banana pulp soluble sugar levels and on peel soluble and total phenolics was measured. One hundred and sixty hands (10 boxes) of banana fruit (Musaacuminata cv. Cavendish) were treated with ethylene (300 μL·L-1, 24 h, 15 °C, 90% RH) at a commercial ripening facility in Bradenton, Fla., and transported by truck (15 °C) to the University of Florida. Fruit were sorted and placed in 174-L ripening chambers, where 80 hands received 500 nL·L-1 1-MCP for two 12-h periods at 18 °C, while the other 80 hands (controls) were maintained in identical containers without 1-MCP for equal time periods at 18 °C. Mean whole fruit firmness in both treatment groups was 140 N and decreased to 15 N (controls) and 30 N (1-MCP) by day 12. Soluble sugars in the pulp of control fruit achieved levels between 160–180 mg·g-1 fresh weight by day 8, while 1-MCP treated fruit required about 12 days to achieve similar soluble sugar levels. Total phenolic compounds present in peel tissue of control and 1-MCP treated fruit required 10 and 14 days, respectively, to achieve levels of about 4000 μg·g-1 fresh weight. Chlorogenic acid levels, a subset of total peel phenolic compounds, peaked above 500 μg·g-1 by day 10 in control fruit and by day 12 in 1-MCP treated fruit. Maintenance of fruit firmness along with the achievement of acceptable sugar levels of 1-MCP treated fruit demonstrate possible benefits of suppression of ethylene action for retail and processing markets for banana fruit.
Brenner L. Freeman, Janet C. Stocks, Dennis L. Eggett and Tory L. Parker
( Cao et al., 1997 ). Antioxidant capacity, anthocyanin content, and total phenolic content are highest when a fruit is ripe ( Wang and Lin, 2000 ). Ripe raspberries have a high antioxidant capacity and total phenolic content compared with most other
Jaime Prohens, Adrián Rodríguez-Burruezo, María Dolores Raigón and Fernando Nuez
, of these, chlorogenic acid (5-O-caffeoylquinic acid and its isomers) typically accounts for 70% to 95% of total phenolics in eggplant fruit flesh ( Stommel and Whitaker, 2003 ). The beneficial effects on health of chlorogenic acid and related
Malkeet S. Padda and David H. Picha
postharvest processing and storage conditions. Previous studies indicated an increase in total phenolic content and antioxidant activity in fresh-cut carrots, potatoes, jicama roots, and lettuce ( Aquino-Bolanos et al., 2000 ; Cantos et al., 2001 , 2002
Karen Salandanan, Marisa Bunning, Frank Stonaker, Oktay Külen, Patricia Kendall and Cecil Stushnoff
conventional melons, especially the differences among cultivars, are limited. In this study, we examined ascorbic acid (AA), total phenolics (TP), radical scavenging capacity 2, 2′-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), and 2,2-diphenyl-1
Jeffrey M. Hamilton and Jorge M. Fonseca
southwestern United States showed an improvement in green color and an increased accumulation of total phenolics (TP) with high salinity in the water ( Fonseca et al., 2009 ; Kim et al., 2008 ). Table 1. Tucson, AZ, 2008, climate data outside a
Gregory M. Peck, Ian A. Merwin, Christopher B. Watkins, Kathryn W. Chapman and Olga I. Padilla-Zakour
with the second harvest for OFP. On the selected harvest date, a 10-fruit subsample was used for measurements of dry matter content and fruit mineral concentration. A different 10-fruit subsample was used for analysis of total phenolic (TP