The Experts below are selected from a list of 1257 Experts worldwide ranked by ideXlab platform

Afzal R. Mohammed - One of the best experts on this subject based on the ideXlab platform.

Per Magne Ueland - One of the best experts on this subject based on the ideXlab platform.

  • determination of vitamins a d and e in a small volume of human plasma by a high throughput method based on liquid chromatography tandem mass spectrometry
    Rapid Communications in Mass Spectrometry, 2011
    Co-Authors: Oivind Midttun, Per Magne Ueland
    Abstract:

    We have developed an automated high-throughput assay for the determination of vitamin A (retinol), Ergocalciferol (25-OH D2), cholecalciferol (25-OH D3) and vitamin E (α-tocopherol) in a small volume of human plasma. Sample preparation involved mixing 50 μL of plasma with 100 μL of ethanol containing isotope-labelled internal standards, followed by mixing with isooctane/chloroform (3:1, 300 μL). The organic phase was evaporated, and the sample reconstituted in 50 μL methanol. The analysis was performed using reversed-phase liquid chromatography with a gradient mobile phase containing water, methanol and ammonium formate. Chromatographic run-time was 5 min, and positive mode electrospray tandem mass spectrometry (MS/MS) was used for detection. The limits of detection were 0.10 μM for all-trans retinol and 3.3 nM for 25-OH D2 and 25-OH D3. Recoveries were 91.9-105.0%, and within- and between-day coefficients of variance (CVs) 2.4-5.3 and 3.1-8.2, respectively. The assay is presently being used in large-scale studies.

Alessandra Gentili - One of the best experts on this subject based on the ideXlab platform.

  • screening and assessment of low molecular weight biomarkers of milk from cow and water buffalo an alternative approach for the rapid identification of adulterated water buffalo mozzarellas
    Journal of Agricultural and Food Chemistry, 2018
    Co-Authors: Chiara Dal Bosco, Roberta Curini, S Panero, Maria Assunta Navarra, Pierpaolo Tomai, Alessandra Gentili
    Abstract:

    Adulteration of Mozzarella di Bufala Campana with cow milk is a common fraud because of the high price and limited seasonal availability of water buffalo milk. To identify such adulteration, this work proposes a novel approach based on the use of species-specific, low-molecular-weight biomarkers (LMWBs). Liquid chromatography–tandem mass spectrometry screening analyses identified β-carotene, lutein, and β-cryptoxanthin as LMWBs of cow milk, while Ergocalciferol was found only in water buffalo milk. Adulterated mozzarellas were prepared in the laboratory and analyzed for the four biomarkers. Combined quantification of β-carotene and Ergocalciferol enabled the detection of cow milk with a sensitivity threshold of 5% (w/w). The method was further tested by analyzing a certificated water buffalo mozzarella and several commercial products. This approach is alternative to conventional proteomic and genomic methods and is advantageous for routine operations as a result of its simplicity, speed, and low cost.

  • comprehensive profiling of carotenoids and fat soluble vitamins in milk from different animal species by lc dad ms ms hyphenation
    Journal of Agricultural and Food Chemistry, 2013
    Co-Authors: Alessandra Gentili, Fulvia Caretti, Simona Bellante, Salvatore Ventura, Silvia Canepari, Roberta Curini
    Abstract:

    This paper describes a novel and efficient analytical method to define the profile of fat-soluble micronutrients in milk from different animal species. Overnight cold saponification was optimized as a simultaneous extraction procedure. Analytes were separated by nonaqueous reversed-phase (NARP) chromatography: carotenoids on a C30 column and fat-soluble vitamins on a tandem C18 column system. Besides 12 target analytes for which standards are available (all-trans-lutein, all-trans-zeaxanthin, all-trans-β-cryptoxanthin, all-trans-β-carotene, all-trans-retinol, α-tocopherol, γ-tocopherol, δ-tocopherol, Ergocalciferol, cholecalciferol, phylloquinone, and menaquinone-4), the DAD-MS combined detection allowed the provisional identification of other carotenoids on the basis of the expected retention times, the absorbance spectra, and the mass spectrometric data. Retinol and α-tocopherol were the most abundant fat-soluble micronutrients and the only ones found in donkey's milk along with γ-tocopherol. Ewe's milk...

Ana Gutiérrez - One of the best experts on this subject based on the ideXlab platform.

  • regioselective hydroxylation in the production of 25 hydroxyvitamin d by coprinopsis cinerea peroxygenase
    Chemcatchem, 2015
    Co-Authors: Esteban D. Babot, José C. Del Río, Lisbeth Kalum, Ángel T. Martínez, Ana Gutiérrez
    Abstract:

    Monohydroxylated metabolites of vitamin D3 (cholecalciferol) and vitamin D2 (Ergocalciferol), generically known as 25-hydroxycalciferol, are better for several diseases, and other applications, than vitamin D (calciferol). This work describes a novel biotechnological approach for the preparation of 25-hydroxycalciferols, starting from readily available cholecalciferol and Ergocalciferol. This approach enables the regioselective (100 %) hydroxylation of these compounds (at the C-25 position) under mild and environmentally friendly conditions by using a peroxidase from the fungus Coprinopsis cinerea (gene model

Cristina Solerrivas - One of the best experts on this subject based on the ideXlab platform.

  • effects of combining electron beam or gamma irradiation treatments with further storage under modified atmospheres on the bioactive compounds of tuber melanosporum truffles
    Postharvest Biology and Technology, 2019
    Co-Authors: Eva Tejedorcalvo, Diego Morales, Pedro Marco, Maria E Venturini, Domingo Blanco, Cristina Solerrivas
    Abstract:

    Abstract The effects of electron-beam or gamma irradiation (both applied at 1.5 kGy and 2.5 kGy) and subsequent storage under modified atmospheres (35 d at 4 °C) were evaluated on total carbohydrates, chitins, β-glucans, proteins, total phenols, sterols and Ergocalciferol concentrations of Tuber melanosporum ascocarps. Irradiation procedures reduced chitin and protein concentrations and modified total phenol levels depending on the dose and irradiation type utilized. Further storage of irradiated truffles maintained the levels of all determined compounds unchanged except for the phenolic compounds and ergosterol levels that increased probably due to their yeast colonization after 21 d storage. Therefore, irradiation plus storage under modified atmosphere packings could be used as a preservation method to extent truffles quality and shelf life, but it is only recommended up to 21 d. The lower irradiation doses are encouraged to diminish protein degradation.