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  • Modern methods to determine vitamin E in foods and feeds
    53-58
    Views:
    76

    Highly specific and sensitive, the proposed fluorometric method for determining α-tocopherol is robust and fairly fast. It
    has been tested in parallel with a conventional thin layer chromatographic method on foods and feeds. The only necessary
    cleanup is the usual saponification. The unsaponificable fraction can be extracted with ethyl ether or, preferably, with
    Extrelut columns. Reagents and their solvents are added to the isooctane solution before each successive reaction and are
    then eliminated by partition with water. The α-tocopherol (α-T) derivative always remains in isooctane. The first step is
    nitrosation and elimination of tocopherols and tocotrienols other than α-isomers. α-T is then oxidized to α-tocored (α-TR)
    with a mixture of sulfuric acid, ferric chloride, and iodine bromide. Α-TR is then condensed to a new reagent: 4,5-dimethylo-
    phenylenediamine. The phenazine formed is strongly fluorescent. Iodine and bromine add to the double bonds of α-
    tocotrienol present and quench the fluorescence of its phenazine.

  • The toxic effects of aflatoxin microorganisms in plants used as spices
    59-62
    Views:
    65

    As an extension of the analysis of black, white and capsicum peppers for aflatoxins , we have examined an additional 11 types of spices and
    4 herbs for these mycotoxins. The investigations consisted of assessment of the applicability of available methods of analysis and modifications of
    these, where necessary together, with a limited survey of each spice and herb for aflatoxins. The analysis of 13 types of ground spices reported
    the presence of low concentrations of aflatoxins in some samples of black pepper, celery seed, and nutmeg. We decided to include in our study 5
    of the spices examined by these workers (cinnamon, celery seed, coriander, nutmeg, and turmeric) for a comparison purpose. In addition we
    examined ginger, mace, cumin seed, dill seed, garlic powder, onion powder, and the herbs marjoram, rosemary, thyme, and sage.

  • The irrigation influence under the soil, microclimate and plants in maize from Crişurilor Plain
    180-186
    Views:
    69

    The paper is based on the researches carried out in the long term trial placed on the preluvosoil from Oradea in 1976, for establishing
    the soil water balance. In the irrigated variant the soil moisture was determined 10 to 10 days for maintaining the soil water reserve on
    irrigation depth (0 – 50 cm for wheat and bean, 0 – 75cm for maize, sunflower, soybean, sugarbeet, potato and alfalfa 1st year and 0 – 100
    cm for alfalfa 2nd year) between easily available water content and field capacity. Thus, an average irrigation rate of 2560 m³/ha was used
    in the 9 experimental crops. The average of the annual rainfall for the 1976 – 2008 period was of 625.0 mm. The technologies used were
    correlated with the needes of the crops, such as melioration crop rotation, chemical fertilizers in accordance with the chemical export on the
    yield, manure (40 t/ha) was used in potato and sugarbeet. After 33 years of the irrigation use the soil structure degree (38.62%) did not
    decrease when compared to the unirrigated maize – wheat crop rotation (37.01%). Bulk density, total porosity, penetration resistance and
    hydraulic conductivity have worse values than the ones in the unirrigated variant. The humus content is very close to the humus content
    determined in 1976, the phosphorus and the potassium content increased very much in comparison with the initial content (117 ppm vs 22.0
    ppm); (180.0 ppm vs 102 ppm). The use of the adequate fertilization system and of the irrigation water with a good qaulity did not determine
    a decrease of the pH value of the soil. The irrigation determined the improve of the microclimate conditions, the increase of the plant water
    consumption, yield gains very significant statistically and higher protein content of the maize grains.