, anthocyanidins, flavanones, isoflavones, and other minor subclasses) and nonflavonoids (including subclasses: phenolic acids, hydroxycinnamates, and stilbenes) ( Crozier et al., 2009 ). Total phenolic content has been shown to be a major contributor to
Adrienne E. Kleintop, James R. Myers, Dimas Echeverria, Henry J. Thompson, and Mark A. Brick
Antonios Petridis, Ioannis Therios, and Georgios Samouris
through a 20-μm polytetrafluoroethylene syringe filter. Total phenol concentration. The total phenol concentration was determined spectrophotometrically at 760 nm using the Folin-Ciocalteu reagent ( Škerget et al., 2005 ). A portion of 125 μL extract was
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
Loutrina Staley, D.G. Mortley, C.K. Bonsi, A. Bovell-Benjamin, and P. Gichuhi
MB and PL enhanced β-carotene in Amaranth compared with NPK but that of Celosia and Gboma was enhanced by MB and NPK fertilizer. Total phenolic content was higher among Amaranth plants receiving NPK, whereas those for Long Bean were greater among
Mohamed S. Al-Saikhan, Luke R. Howard, and J. Creighton Miller Jr.
Two varieties of yellow flesh (Granola and Yukon Gold) and two white flesh (Viking and Russet Norkotah) potatoes were grown near Springlake, Texas in the summer of 1992. Varieties were investigated for their antioxidant activity and total phenolic content. Varieties were significantly different in antioxidant activity and total phenolic content (P = 0.0001). Granola had the highest antioxidant activity and Russet Norkotah the highest total phenolic content, while Yukon Gold had the lowest antioxidant activity and total phenolic content. Further study was conducted on tuber parts (distal end, center, and stem end) and among sections within each tuber part. Differences were slight among tuber parts in antioxidant activity, but significant in total phenolic content. Moreover, the differences were slight among the three sections for antioxidant activity and total phenolic content, while the fourth section containing the skin (epidermal tissue) had the highest antioxidant activity and total phenolic content.
M.E. Garcia, C.R. Rom, and J.B. Murphy
The effects of shading and leaf age on the production of foliar phenolics of two apple (Malus domestica Borkh.) cultivars, `Liberty' and `Red Rome Beauty', were studied. Potted trees were grown outdoors and their leaves tagged weekly when they reached 20 mm in length. This process continued for the duration of the experiment. At 3 weeks from budbreak, the trees were placed in three shade treatments: 0% shade (control), 60% shade, and 90% shade. After 5 weeks, the leaves were collected for phenolic assay. Specific leaf weight (SLW) was determined from the leaf below the tagged leaf. Shade significantly affected the total phenolic content. Leaves in 0% shade had the highest levels of total phenolics. The phenolic content decreased with increasing shade, with trees in 90% shade having a 72% reduction in total phenolics. There was a significant shade by leaf age interaction. There was a decrease in total phenolic content with increasing leaf age except for those leaves whose development occurred before the experiment was started. The 1-week-old leaf had the highest phenolic content, while 4-week-old leaf had the lowest amount. The 5- and 6-week-old leaves that had been tagged prior to the onset of the shade treatments has similar phenolic content in all treatment. SLW significantly decreased with increasing shade and increased with leaf age. Results of this study indicate that light and leaf developmental stage are important factors in the total foliar phenolic content, but, once phenolics are synthesized, shading does not affect their content.
Xin Zhao*, Janice E. Young, Ted Carey, and Weiqun Wang
Organic vegetables have been suggested to produce higher levels of phytochmemicals, which play active roles in disease prevention. We measured total phenolic and aglycone flavonoid (apigenin, kaempferol, luteolin, and quercetin) contents in leaves of organically- and conventionally-grown lettuce (`Kalura' and `Red Sails'), collards (`Top Bunch') and Pak Choi (`Mei Qing') greens during spring and summer trials, using the Folin assay and HPLC, respectively. Postharvest changes in phenolic contents of organic and conventional lettuce were also investigated after 17-day storage at 4 °C. Production system did not cause a significant difference in total phenolic levels of lettuce and collards in either trial, but total phenolics were significantly higher in organic Pak Choi in the summer trial, possibly due to greater flea beetle damage in the organic plots. Organic production did not affect the aglycone flavonoid levels of lettuce and collards in the spring trial except that apigenin increased in organic samples. In the summer trial, however, concentrations of kaempferol, luteolin and quercetin tended to increase in organic lettuce and collards; only luteolin showed promising increase in Pak Choi. Species and cultivars both had significant effects on total phenolic and flavonoid contents. After 17-day storage, total phenolic content significantly increased in both organic and conventional lettuce although the concentrations of aglycone flavonoids remained relatively constant. Total phenolic content was higher in organic `Red Sails' at a marginal significance level after storage, while it did not differ between organic and conventional `Kalura'. We noted a dominant presence of glycoside flavonoids in lettuce before and after storage, which warrants further study.
Penelope Perkins-Veazie, Brent Black, Ingrid Fordham, and Luke Howard
Autumn olive (Elaeagnus umbellata) is a small red berry that grows on shrubs from Maine to Alabama. This plant originated in China and was introduced to the U.S. in the late 1800s for erosion control. About 20% of the berry' fresh weight is in its single, large seed. The berries of Autumn olive are extremely rich in lycopene (30–50 mg/100 g). The berries are astringent, indicating that fruit may be high in phenolic compounds as well as carotenoids. There has been great interest in producing the plants in domesticated plantings, and in using the fruit as a natural source of lycopene.
This study was done to determine the relative contents of lycopene and phenolics among selections and varieties of autumn olive. The lycopene content of six selections and varieties was 30 to 55 mg·g–1. The lycopene content of berries did not increase after 4 days storage at 25 °C followed by 2 days at 5 °C. Autumn olives are high in soluble solids content (11% to 17%), and relatively high in acidity (1.7% to 5.5% citric acid). The astringent flavor of the berries may be due to the high total phenolic content (1700 mg·kg–1 chlorogenic acid equivalents). The berries were found to be high in flavanols and hydroxybenzoic acids (33 rutin and 31 gallic acid mg·kg–1 equivalents), while the seeds were high in hydroxycinnamic acids and extremely high in hydroxybenzoic acids (35 chlorogenic acid and 184 gallic acid mg·kg–1 equivalents).
Ann Marie Connor, Chad E. Finn, and Peter A. Alspach
Antioxidant compounds absorbed from our diet are thought to have a role in preventing chronic diseases that result from oxidative damage. Berry fruit have high levels of antioxidants, and further increases in antioxidant activity (AA) might be possible through breeding. We determined the AA, total phenolic content (TPH), and fruit weight in 16 blackberry and hybridberry (Rubus L.) cultivars harvested in New Zealand and Oregon in 2002 and 2003, to assess genetic and environmental variation. Both AA and TPH varied significantly between years within location, but not among cultivars or between locations per se. However, cultivar interactions with both location and year within location contributed to variation in both variates. In contrast, both cultivar and location contributed to variation in fruit weight, but years within location did not. However, the cultivar × year within location interaction was significant for this trait. Variance component distributions confirmed that cultivar and location effects together contributed little (<20%) to the total variation in either AA or TPH, while cultivar × environment interactions accounted for >50% of total variation in these traits. Cultivar and location effects together contributed ≈70% of the total variation observed in fruit weight. Phenotypic correlations were significant between AA and fruit weight (r = -0.44), and between TPH and fruit weight (r = -0.51). When adjusted for fruit weight, analyses for AA and TPH demonstrated that cultivar effects approached significance (P = 0.06) and accounted for ≈25% of total variance, while location effects accounted for none. Although the cultivars in this study had diverse interspecific backgrounds, utilization of various Rubus species in blackberry and hybridberry breeding is not uncommon, and our results demonstrating significant cultivar × environment interaction for AA and TPH should be applicable to breeding for high AA genotypes.
Ann Marie Connor, James J. Luby, and Cindy B.S. Tong
Narrow-sense heritability and among-family and within-family variance components were estimated for antioxidant activity (AA), total phenolic content (TPH), and anthocyanin content (ACY) in blueberry (Vaccinium L. sp.) fruit. AA, TPH, and ACY were determined in the parents and in 10 offspring from each of 20 random crosses for each of 2 years at Becker, Minn. Offspring-midparent regression analysis provided combined-year heritability estimates of 0.43 ± 0.09 (P ≤ 0.0001) for AA, 0.46 ± 0.11 (P ≤ 0.0001) for TPH, and 0.56 ± 0.10 (P ≤ 0.0001) for ACY. Analyses of variance delineated variation among and within families for AA, TPH, and ACY (P ≤ 0.001). Year-to-year variation in the means for all offspring genotypes was not significant for AA or TPH, but there were changes in rank between years for families and for offspring within families for these traits. Year-to-year variation in the mean for all offspring genotypes was significant for ACY, but rank changes were observed only among offspring within families, not among families. In total, 18 of 200 offspring from 7 of the 20 crosses were transgressive segregants for AA, exceeding the higher parent of the cross by at least two sds. Estimates of variance components showed that variation among families accounted for 24% to 27% of total variance for the three traits. However, variation within families was greater than that among families, accounting for 38% to 56% of total variance for the three traits. These results suggest that increasing antioxidant activity in blueberry through breeding is feasible, and that the breeding strategies utilized should exploit the large within-family variation that exists.