Phenolic composition of champagnes from Chardonnay and Pinot Noir vintages

Nineteen phenolic compounds including hydroxybenzoic acids, hydroxycinnamic acids, flavonoids, phenolic alcohols, and phenolic aldehydes have been identified and quantified in two monovarietal champagnes, Chardonnay and Pinot Noir, by using a reverse-phase high-performance liquid chromatography (HPLC) system coupled with diode array detection. The identification of four hydroxycinnamic tartaric esters (caftaric, coutaric, fertaric, and 2-S-glutathionylcaftaric acids), two flavanonols (astilbin and engeletin), and some other compounds was confirmed by HPLC coupled with mass spectrometry. Caftaric acid and tyrosol were the major phenols. Hydroxybenzoic acids and flavonoids were present at low concentrations. The phenolic compositions of 2000 and 2001 Chardonnay and Pinot Noir vary quantitatively according to the year and the variety, but the chemical natures of the molecules are the same. The total phenolic content determined by colorimetric measurement ranges from 176 to 195 mg/L of gallic acid equivalent and is similar to that described in white wines.     

Isolation and characterisation of biologically-active compounds from some plant extracts

Of the numerous fractions obtained from the crude plant extracts of Chenopodium ambrosioides, Conyza dioscordisis and Convolvulus arvensis, 11 were found to be active against stored grain pests. The chemical structures of compounds present in the 11 fractions were found by gas chromatography/mass spectrometry to include predominantly long-chain fatty acid esters of hexadecanoic, arachidonic, and octadecanoic acids.     

Effectiveness of mating disruption with TUTATEC® dispensers against Tuta absoluta (Lepidoptera: Gelechiidae) in heated greenhouses in southern Tunisia

Phytoparasitica - Tomato production in geothermal greenhouses in Tunisia showed remarkable growth during the last decade and has been considered an important economic sector within the Tunisian...     

Characterization of the Exoglucanase-Encoding Gene PaEXG2 and Study of Its Role in the Biocontrol Activity of Pichia anomala Strain K

ABSTRACT The PaEXG2 gene, encoding an exo-beta-1,3-glucanase, was isolated from the biocontrol agent Pichia anomala strain K. PaEXG2 has the capacity for coding an acidic protein of 427 amino acids with a predicted molecular weight of 45.7 kDa, a calculated pI of 4.7, and one potential N-glycosylation site. PaEXG2 was disrupted by the insertion of the URA3 marker gene, encoding orotidine monophosphate decarboxylase in strain KU1, a uracil auxotroph derived from strain K. Strain KU1 showed inferior biocontrol activity and colonization of wounds on apples, compared to the prototrophic strain. Antagonism and colonization were recovered after the restoration of prototrophy by transformation with the URA3 gene. Integrative transformation was shown to be mostly ectopic in strain K descendants (only 4% of integration by homologous recombination). PaEXG2 disruption abolished all detectable extracellular exo-beta-1,3-glucanase activity in vitro and in situ but did not affect biocontrol of Botrytis cinerea on wounded apples.     

Impact of browning reactions and bran pigments on color of parboiled rice

Rice color changes from white to amber during parboiling (soaking and steaming). Color parameters indicated that, during soaking, yellow bran pigments leached out in the water. The levels of the Maillard precursors (i.e., reducing sugars (RS) and free alpha-amino nitrogen (FAN)) depended on soaking temperature and time: leaching of RS was compensated by enzymic formation for long soaking times (>60 min), while proteolytic activity was too low to compensate for FAN leaching. Rice soaking under nitrogen, oxygen, or ambient conditions and determination of polyphenol oxidase activity allowed us to conclude that the effect of enzymic color changes on the soaked rice color was rather small. Color measurements of brown and milled mildly, intermediately, and severely parboiled rice samples showed that both brown and milled rice samples were darker and more red and yellow after parboiling and that the effect depended on the severity of parboiling conditions. Furthermore, steaming affected the rice color more and in a way opposite to that observed in soaking. The changes in RS and the loss of FAN during parboiling suggested that Maillard type reactions occur during brown rice steaming. Analyses of furosine levels confirmed Maillard browning of outer bran layers and endosperm during steaming. The level of this Maillard indicator increased with the severity of parboiling conditions in both brown and milled parboiled rice. Measurements of the levels of bran pigments indicated that bran pigments diffuse into the endosperm during parboiling and contribute to the parboiled rice color.     

Integrated pest management of Tuta absoluta: practical implementations across different world regions

Journal of Pest Science - The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), has invaded most Afro-Eurasian countries and is threatening worldwide tomato...     

Denitrification and nitrogen immobilization as affected by organic matter and different forms of nitrogen added to an anaerobic water-sediment system

The effects of wheat straw and different forms of N on denitrification and N immobilization were studied in an anaerobic water-sediment system. The water-sediment system was supplemented with various combinations of wheat straw and ¹⁵N-labelled and unlabelled (NH₄)₂SO₄ or KNO₃, and incubated anaerobically at 30°C for 10 days. ¹⁵N-labelled and unlabelled NO _inf3 ^sup- , NO _inf2 ^sup- , NH _inf4 ^sup+ , and organic N were determined in the water-sediment system. The gases evolved (N₂, CO₂, N₂O, and CH₄) were analyzed by gas chromatography at regular intervals. Larger quantities of ¹⁵N₂–N and organic ¹⁵N were formed in wheat straw-amended systems than in non-amended systems. Trends in CO₂ production were similar to those of N₂–N evolution. The evolution of N₂O and CH₄ was negligible. Denitrification processes accounted for about 22 and 71% of the added ¹⁵NO _inf3 ^sup- –N in the absence and presence of wheat straw, respectively. The corresponding denitrification rates were 3.4 and 12.4 g ¹⁵Ng^-1 dry sediment day^-1. In systems amended with ¹⁵NO _inf3 ^sup- –N and ¹⁵NO _inf3 ^sup- +NH _inf4 ^sup+ –N without wheat straw, 1.82 and 1.58%, respectively, of the added ¹⁵NH _inf3 ^sup- –N was immobilized. The corresponding figures for the same systems supplemented with wheat straw were 5.08 and 4.10%, respectively. Immobilization of ¹⁵NO _inf4 ^sup+ –N was higher than that of ¹⁵NO _inf3 ^sup- –N. The presence of NO _inf3 ^sup- –N did not stimulate NH _inf4 ^sup+ –N immobilization.