Although fruits obtained by organic cultivation (OC) have been believed to be healthier than those by conventional cultivation (CC), but clear experimental evidences supporting the assumption are still lacking. Therefore this study was carried out to investigate the effects of OC on total polyphenol content and anti-oxidant activity in `Hongro' apples (Malus domestica). Anthocyanin content of fruit skin was increased in apples from OC. Soluble solid content and pH of apple juice was higher in the OC than in the CC, but total acidity in fruit juice showed reversed result. Also, chlorophyll content showed no difference between OC and CC. Total polyphenol compounds extracted with methanol, were higher in the OC than in the CC, and also higher in peel than in flesh. Also, anti-oxidant activity estimated by free radical scavenging effect showed significantly stronger under the OC than the CC.
Wol-Soo Kim* and Jung-An Jo
Renata Koyama, Adriane Marinho de Assis, Lilian Yukari Yamamoto, Wellington Fernando Borges, Rogério de Sá Borges, Sandra Helena Prudêncio, and Sergio Ruffo Roberto
containers with lids and a capacity of 1 L. After cooling, juice bottles were stored in the refrigerator at 4 °C for further anthocyanin, polyphenol, and sensory analyses. Anthocyanin extraction. The concentrations of total anthocyanins of berries and juices
Steven F. Vaughn
Localization of enzymes in specific plant tissues is crucial to understanding their role in processes such as differentiation and disease resistance. The oxidative enzymes lipoxygenase (LOX; EC 126.96.36.199), peroxidase (PER, EC 188.8.131.52) and polyphenol oxidase (PPO; EC 184.108.40.206) have all been implicated as playing critical roles in plant disease resistance. The histochemical localization of all three enzymes in potato tuber slices was accomplished either directly on the tissue slices (for LOX) or by blotting of the tissue onto nitrocellulose membranes (for PER and PPO). LOX was visualized in specific tissues by the oxidation of KI to I2 via lipid peroxides and the subsequent reaction of I2 and endogenous starch to form a colored, insoluble complex. PER and PPO activities were visualized with 4-methoxy-α-naphthol and 3,4-dihydroxy-phenylalanine, respectively. Fractionation of the slices and determination of enzyme activities in the fractions confirmed the reliability of these techniques.
Roger L. Vallejo, Wanda W. Collins, and Robert H. Moll
Glandular trichomes from some Solanum species have suppressed infestation by insects including green peach aphid, which is a main vector of potato virus Y (PVY) and potato leaf roll virus (PLRV), both of which contribute to a serious loss in potato production. Eight Solanum phureja Juz. et Buk.-S. stenotomum Juz. (Phu-Stn), three S. berthaultii Hawkes (Ber), nine F1 [(Phu-Stn) × Ber], fifteen backcross (BC) [(Phu-Stn) × F1], and seventeen reciprocal BC (BCR) [F1 × (Phu-Stn)] families were evaluated to determine the genetic variability and heritability of A and B glandular trichome density and polyphenol oxidase (PPO) activity. Experiments were carried out in completely randomized and randomized complete-block designs in the greenhouse. Genetic analysis was done using half-sib family and parent-offspring regression analysis. Phu-Stn showed a higher density of A trichomes than Ber and F1, while the BC and BCR had densities of A trichomes similar to Phu-Stn. B trichomes were not observed in Phu-Stn. Ber showed a high B trichome density, which was transmitted to the F1. In the BC, B trichomes were almost absent, but, in the BCR, the density of B trichomes was higher than that of BC. Ber and F1 had similar or higher PPO activity than Phu-Stn. PPO activity decreased in the BC, but, in the BCR, it was high and similar to Ber and F1. Broad-sense heritability estimates for A and B trichome density and PPO activity were from medium to high (0.48 to 0.77) in Phu-Stn, Ber, and F1. Narrow-sense heritability estimates for A and B trichome density and PPO activity were very low (0.04 to 0.24) in BC and BCR. In the BC families, additive genetic variance was very low for A and B trichome density and PPO activity. Half-sib family selection based on progeny testing and combined with BCs to Phu-Stn in subsequent generations would be a suggested breeding procedure to improve these traits. Phenotypic correlations between A and B trichome densities were 0.26 (F1) and 0.44 (BCR), between A trichome density and PPO activity 0.20 (F1) and 0.31 (BCR), and between B trichome density and PPO activity 0.04 (F1) and 0.27(BCR. Positive associations found between traits might facilitate simultaneous improvement for high levels of A and B trichome density and PPO activity.
Hanah T. Rheay, Kevin Lombard, Catherine Brewer, and F. Omar Holguin
well as polyphenols, particularly xanthohumol, for nutraceutical properties. Study objectives were to survey neomexicanus hop cone chemistry and compare results to the chemistry of ‘Cascade’ common hops. Materials and methods Plant material. ‘Multi
Roger L. Vallejo, Wanda W. Collins, and Rocco D. Schiavone
Preliminary data on the genetics of glandular trichomes and the feasibility of incorporating A and B glandular trichomes and polyphenol oxidase (PPO) activity from Solanum berthaultii Hawkes (Ber) into an advanced S. phureja Juz. et Buk.-S. stenotomum Juz. (Phu-Stn) diploid potato population are presented. A random sample of four Phu-Stn clones was intercrossed with a sample of three Ber progenies (pollen bulk per progeny) segregating for high density of A and B glandular trichomes. Nine F1 families [(Phu-Stn) × Ber] were evaluated over two experiments in the greenhouse for A and B trichome density (5 mm2 of abaxial surface) and PPO activity 45 days after planting. A completely randomized design in an experimental hierarchical classification arrangement was used to quantify the genetic variability and to estimate broad-sense heritabilities (defined on an individual basis) for the attributes under study. To characterize the inheritance of these attributes further and to estimate narrow-sense heritabilities, fifteen backcross (BC) families were evaluated in a randomized complete-block design with three replications and analyzed by half-sib family analysis. Phenotypic and genotypic correlations between these attributes were also estimated. In the F1 families, broad-sense heritabilities were 0.59 and 0.41 for density of A and B trichomes, respectively. In the BC population, narrow-sense heritabilities were 0.15 and 0.08 for A trichome density and PPO activity, respectively; expression of B trichomes was almost absent in this generation. Genotype × environment interaction was significant for density of A trichomes and highly significant for density of B trichomes in F1 families. There was some level of positive association between density of A and B trichomes and PPO activity. Additive genetic variance of these attributes was very low in this study; therefore, selection schemes based on family selection and progeny testing would be an appropriate breeding strategy for improving these traits.
R. Fernández-Escobar, G. Beltrán, M.A. Sánchez-Zamora, J. García-Novelo, M.P. Aguilera, and M. Uceda
Mature `Picual' olive (Olea europaea L.) trees growing in two different localities of Córdoba and Jaén provinces, southern Spain, were subjected to annual applications of 0, 0.12, 0.25, 0.50, or 1.0 kg N/tree in the Cordoba's experiment, and to 0 or 1.5 kg N/tree in the Jaén's experiment. Nitrogen was applied 50% to the soil and 50% through foliar application in Córdoba, and 100% to the soil in Jaén. Three years after the initiation of treatments, when the trees showed differences among them in nitrogen content, fruit were sampled at maturity from each experimental tree during six consecutive seasons to determine the effect of nitrogen fertilization on olive oil quality. Tree nitrogen status was always above the threshold limit for deficiency even in control trees, indicating that most treatments caused nitrogen over fertilization. Nitrogen in excess was accumulated in fruit and, consequently, polyphenol content, the main natural antioxidants, significantly decreased in olive oil as nitrogen increased in fruit. The decrease in polyphenols induced a significant decrease in the oxidative stability of the oil and its bitterness. Tocopherol content, on the contrary, increased with nitrogen application, mainly by an increase in α-tocopherol, the main component in the olive oil. No effect was found on pigment content, particularly carotenoid and chlorophyllic pigments, neither on fatty acid composition.
Lajos Helyes, Zoltán Pék, Sára Brandt, and Andrea Lugasi
Tomato (Lycopersicon esculentum) fruit is an important source of antioxidants, which are important in the prevention of many cancer types and cardiovascular diseases. In ripe tomato fruit, one of the most significant antioxidant compounds is lycopene. In this study, effects of the cultivars and the environmental conditions on the lycopene content were investigated. Temperature effect was characterized by calculating growing degree-day (GDD). Relationships among lycopene, total polyphenols, organic acid, and total antioxidant status (TAS) were analyzed. A variation of more than 30% was found among the lycopene levels of five processing tomato cultivars. Lycopene content ranged from 79.7 to 155.0 mg·kg–1 fresh weight. There was a significant difference between the lycopene concentrations of fruit harvested at two different dates. The values were higher at the second harvest, probably due to the cooler weather conditions preceding that harvest. Total polyphenols correlated strongly with TAS but the other antioxidants did not have any relationship to TAS. GDD were strongly and positively correlated with hydroxymethylfurfural content in fresh tomatoes.
Maria J. Berenguer, Paul M. Vossen, Stephen R. Grattan, Joseph H. Connell, and Vito S. Polito
A comparative study was conducted to evaluate the influence of seven different levels of irrigation applied to `Arbequina I-18' olive (Olea europaea L.) trees grown in a super-high-density orchard (1,656 trees/ha) in the Sacramento Valley of California. Water was applied differentially by drip irrigation at rates of 15%, 25%, 40%, 57%, 71%, 89%, and 107% evapotranspiration (ETc) in 2002, and 28%, 33%, 55%, 74%, 93%, 117%, and 140% ETc in 2003. Each treatment was replicated three times. Olives were harvested on two different dates each year from each of 21 plots. Three of four harvest dates showed a decrease in maturity index with increasing irrigation levels. Oils were made from olive samples collected from each plot and analyzed for oil quality parameters. Total polyphenol levels and oxidative stability decreased as the trees received more water, especially for the three lowest irrigation treatment levels in 2002, but few differences were noted between treatments in 2003 when all the trees were irrigated more heavily. Average oxidative stability was correlated very closely with total polyphenol content with r 2 = 0.98 in 2002 and 0.94 in 2003. In 2002, free fatty acid levels increased and peroxide levels were unchanged, but in 2003, free fatty acid levels were unchanged and peroxide levels decreased in treatments receiving more water. Saturated fatty acids did not significantly change in 2002, due to tree irrigation level. The mono-unsaturated fatty acid levels and oleic–linoleic relationship declined while poly-unsaturated fatty acid levels increased in 2002 with increased irrigation. In 2003, there was no notable difference in the ratio of mono to poly unsaturated fatty acid levels. The individual fatty acid most consistently affected by more irrigation water was stearic, which decreased in both years. Total sterol content (mg·kg–1), percentages of cholesterol and erythrodiol were significantly influenced by tree irrigation levels, but increased in one year and either decreased or were unchanged the next. Oil sensory properties of fruitiness, bitterness, and pungency all declined in oils made from trees receiving more water. The lowest irrigation levels produced oils that were characterized by excessive bitterness, very high pungency, and woody, herbaceous flavors. Intermediate irrigation levels (33% to 40% ETc) produced oils with balance, complexity, and characteristic artichoke, grass, green apple, and some ripe fruit flavors. Higher irrigation levels lowered oil extractability and produced relatively bland oils with significantly less fruitiness and almost no bitterness or pungency.
Yanina Perez Cayo, Steven Sargent, Cecilia do Nascimento Nunes, and Vance Whitaker
goal of the breeding program. Toward this goal, the breeding program seeks to quantify and enhance important chemical components in strawberry fruit that may impact appearance, flavor, and nutritional value. Sugars, acids, and polyphenols contribute