Extraction of Antioxidants from Wheat Bran Using Conventional Solvent and Microwave-Assisted Methods

Total phenolic and tocopherol contents and free radical scavenging capability of wheat bran extracted using conventional and microwave-assisted solvent extraction methods were studied. Three different solvents (methanol, acetone, and hexane) were used in the conventional solvent extraction. Methanol was the most effective solvent, producing higher extraction yield (4.86%), total phenolic compound content (241.3 μg of catechin equivalent/g of wheat bran), and free radical scavenging capability (0.042 μmol of trolox equivalent/g of wheat bran) than either acetone or hexane. However, there was no significant difference in the total tocopherol contents (13.6–14.8 μg/g of wheat bran) among the three different solvent extraction methods. Microwave-assisted solvent extraction using methanol significantly increased the total phenolic compound content to 467.5 and 489.5 μg of catechin equivalent; total tocopherol content to 18.7 and 19.5 μg; and free radical scavenging capability to 0.064 and 0.072 μmol of trolox equivalent/g of wheat bran at extraction temperatures of 100 and 120°C, respectively. However, extraction yields of conventional methanol solvent and microwave-assisted methanol extractions at different temperatures were not significantly different.     

Titanium oxide nanoparticle effects on composition of soil microbial communities and plant performance

We examined the effect of TiO₂ nanoparticles (NPs) on the growth of maize and soybean plants and associated soil microbial communities. Plants were grown in a greenhouse, and low levels of undoped or nitrogen-doped TiO₂ NPs were applied. Plant growth and nutrient content were determined, and effects of NPs on composition of soil microbial communities were examined using terminal restriction fragment length polymorphism analysis (TRFLP) of rDNA. We found no significant effects of TiO₂ NPs on plant growth, nutrient content, or the composition of bacterial communities within the rhizosphere. However, arbuscular mycorrhizal fungal communities were affected by application of undoped and nitrogen-doped TiO₂ NPs. This observation may be partially attributed to the small but significant TiO₂ NP uptake levels in the root tissues of both plants. Our results suggest that even low concentrations of TiO₂ NPs may influence some important groups of soil microbes, such as mycorrhizal fungi, but changes in the composition of microbial communities may not affect plant growth under conditions of adequate moisture and nutrients.     

Response of primary plant metabolism to the N-source

Even when plant growth was not visibly affected, ammonium versus nitrate nutrition had distinct effects on some parts of plant metabolism. Barley seedlings growing on 3 mM ammonium rapidly accumulated ammonium up to 20 mM in the roots. In leaves, ammonium accumulation was observed only when the pH of the nutrient medium was very low (pH 4). Yet even under the most extreme conditions there was no indication that plants were suffering from uncoupling of ATP synthesis or from a lack of carbohydrates. Especially dramatic was the response of the organic acid content of pea and barley leaves: it decreased strongly within a few days upon transfer of plants from nitrate to ammonium-media, and this was apparently not due to an inhibition of PEPcarboxylase, which was rather activated under ammonium nutrition. As malate dispappeared from leaves even when pea plants were transferred to an N-free medium, malate degradation was not necessarily connected to increased amino acid synthesis, but eventually to a more rapid decarboxylation by malic enzyme. Also, malate degradation was not a response to ammonium, but rather to (the absence of) nitrate.     

Extractable iron and organic matter in the suspended insoluble material of fog droplets

In this work the formation and composition of aggregates between metals and organic material is studied in real fog samples. In a preliminary experiment it has been found that concentrated cloud samples form a yellow-brown precipitate in the presence of Fe(III). Standards of humic acids and fulvic acids co-precipitate with Fe(III), forming similar aggregates i.e. iron-humates (Fe-HA) and iron-fulvates (Fe-FA). By comparing the solubility properties of aggregates by extracting organic carbon (OC) in different pH conditions, it has been observed that fog droplet particulate samples are characterised by solubility properties more similar to those of Fe-HA than Fe-FA. Dilute alkaline solutions can also easily extract organic refractory substances that form aggregates with metals. The recoveries of the total extractable organic matter (accounting for 12% of total insoluble carbon and 15% of particulate mass) are similar to those of humic-like substances (HULIS) from particulate samples. The chromatographic behaviour and functional group characteristics measured in the alkali-extract fraction of precipitated aggregates with iron and in the insoluble particulate of fog samples, are those of humic-like material. Thus, soluble HULIS are able to interact with iron to form particulate, but the composition of a large fraction of insoluble organic carbon is still unknown. These findings have implications on the solubility and surface tension properties of fog droplets and can therefore potentially influence droplet formation, as well as cloud chemical and photochemical processes.     

New beverages of lemon juice enriched with the exotic berries maqui, açaı́, and blackthorn: bioactive components and in vitro biological properties

Following previous research on lemon juice enriched with berries, the aim of this work was to design new blends based on lemon juice mixed with different edible berries of exotic and national origin: maqui ( Aristotelia chilensis (Molina) Stuntz), a?a?? ( Euterpe oleracea Mart.), and blackthorn ( Prunus spinosa L.). The phytochemical characterization of controls and blends was performed by HPLC-DAD-ESI/MS(n). Their antioxidant capacity against DPPH, superoxide, and hydroxyl radicals and hypochlorous acid and their potential to inhibit cholinesterases were also assessed. The profiling of the red fruits and lemon revealed a wide range of bioactive phenolics. The novel beverage based on lemon juice and maqui berry (LM) was the most interesting blend in terms of antioxidant capacity. Berry control samples displayed reduced effects on acetylcholinesterase and butyrylcholinesterase, the lemon juice control being always the most active. This activity was also remarkable for lemon-blackthorn (LB) and lemon-a?a?? (LA) blends, the last being the most effective inhibitor of cholinesterases among all samples. The results suggested that lemon juice enriched with berries could be of potential interest in the design of new drinks with a nutritive related function on health for chronic diseases.     

Implications of early selection for grain colour on iron and zinc content and productivity of common bean

Brazilian consumers prefer beans of the beige grain colour. Common beans help supply dietary requirements for iron and zinc. The objectives of this study were (i) to determine whether early selection for grain colour affects the iron and zinc content and the grain yield in common beans and (ii) if an association between these characteristics was found, to obtain lines of carioca‐type grains with a high iron and zinc content and good grain yield. We evaluated 96 F_3:4, F_3:5 and F_3:6 progeny at two locations for iron and zinc content and grain yield. We selected 48 progeny for grain colour and chose 48 others at random. We found that early selection for grain colour does not affect the zinc content and grain yield. A positive and high association was found between iron and zinc content, and both iron and zinc content were slightly negatively correlated with grain yield. It is possible to obtain common bean lines combining a high iron and zinc content with good grain yield as long as a selection index is used.     

Identification of sex in Carica papaya L. using RAPD markers

Brazil is currently the worlds largest producer of papaya (Carica papayaL.), producing fruits for both the domestic market and export. Only fruits from hermaphrodite plants are marketed because they have the necessary commercial characteristics, i.e. they are pear-shaped and have thicker flesh and a smaller internal cavity. Increased papaya yield has been limited mainly by the ratio of female to hermaphrodite (1: 2) plants normally occurring in orchards. This ratio causes great losses to papaya producers and the identification of the sex of seedlings during the nursery stage would be an important advance. In our study random amplified polymorphic DNA (RAPD) analysis was used to differentiate between the sexual forms of three commercial C. papaya cultivars belonging to the Solo group. RAPD assays using the BC210 primer were able to detect hermaphrodites in all of the cultivars tested. The BC210₄₃₈molecular marker was much better at papaya sex differentiation than other markers described in the literature. This revised version was published online in August 2006 with corrections to the Cover Date.     

Arabinogalactan proteins may facilitate the movement of pollen tubes from the stigma to the ovules in Actinidia deliciosa and Amaranthus hypochondriacus

Sexual plant reproduction is a complex process that involves a series of interactions between the male gametophyte and the different cell types of the pistil. These interactions are believed to direct the pollen tube growth until its final target, the embryo sac. Arabinogalactan proteins are complex proteoglycans that are believed to be involved in these processes. The pistil is enriched in these highly glycosylated proteins and we provide results that show the selective presence of different AGP epitopes at the surface of the cells or in the ECM of the tissues that correspond exactly to the pollen tube growth pathway in Amaranthus hypochondriacus and Actinidia deliciosa. We also show that in Actinidia deliciosa, which is a dioecious plant with the male flowers having rudimentary ovaries where fertilization does not occur, there is no presence at all of the epitopes recognised by the monoclonal antibodies utilized in this study. This revised version was published online in July 2006 with corrections to the Cover Date.     

Use of culture-derived Fusarium oxysporum f. sp. cubense, race 1 filtrates for rapid and non-destructive in vitro differentiation between resistant and susceptible clones of field-grown banana

Banana and plantain are among the most important food crops in developing countries but production is threatened by increasing virulent forms of Fusarium oxysporum f. sp. cubense. Chemical control is not economically effective and,therefore, breeding programs are necessary. Traditional field studies of new genotype resistance to this disease are time-consuming and destructive. Therefore,we developed a rapid and non-destructive procedure to differentiate field-grown banana resistant from susceptible clones. This procedure implicates application of culture filtrates of Fusarium oxysporum f. sp. cubense race 1 onto banana leaves. The relationship between duration of the fungal in vitro incubation, and the fungal culture fresh mass, the culture filtrate absorbency, and the Gross Michel (susceptible cultivar)leaf lesion area (after application of the culture filtrate) were similar and at 24day-incubation the highest values of the recorded indicators were observed. A comparison between Gross Michel and FHIA-01(resistant) was also performed. The most relevant differences between cultivars were observed at 48 hours after application of the culture filtrate, and in the middle-aged leaves. The position of the culture filtrate application in the leaf limb (distal, middle, proximal) was not determinant. A wider comparison among banana cultivars confirmed previous results informed by other researchers using different systems to study this plant-fungus interaction. Such a confirmation validates the effectiveness of the procedure described here to select rapid and non-destructively banana resistance to this disease at field level. This revised version was published online in August 2006 with corrections to the Cover Date.     

Segregation and associations of enological and agronomic traits in Graciano × Tempranillo wine grape progeny (Vitis vinifera L.)

The main objective of this research was the evaluation of the variability present in a segregating wine grape population derived from a cross between Graciano × Tempranillo, two Spanish varieties, in order to select improved genotypes with potential for producing high-quality wines in a climate change scenario. For that purpose, the phenotypic segregation of 16 agronomic traits related to production and phenology and 11 enological traits related to technical and phenolic maturity was studied in the progeny for three consecutive years. All traits presented transgressive segregation and continuous variation. Year effect was significant for all traits except total, extractable and skin anthocyanins content. However, a high level of genotype consistency for enological traits was revealed by repeatabilities and correlations between years. Significant correlations among traits were observed but most associations were weak. Furthermore, the CAPS (Cleaved Amplified Polymorphic Sequence) marker for the VvmybA genotype was tested to determine whether it would be useful in indirect selection for berry anthocyanins content. The results showed that the number of homozygous and heterozygous genotypes for the functional colour allele adjusted to a 1:1 segregation ratio, and that homozygous genotypes had significantly higher anthocyanins content. Principal component analysis found eight variables that contributed up to 80 % of the phenotypic variability present in the population. Seven groups of hybrids were distinguished based on ripening time, cluster weight, berry weight and anthocyanins content by cluster analysis; and fourteen genotypes were pre-selected for further research.