Ústav chemie potravin a biotechnologií

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    Calibration for Quantitative Chemical Analysis in IR Microscopic Imaging
    (2025-10-06) Magnussen, Eirik Almklov; Zimmermann, Boris; Dzurendová, Simona; Slany, Ondrej; Tafintseva, Valeria; Liland, Kristian Hovde; Tondel, Kristin; Shapaval, Volha; Kohler, Achim
    Infrared spectroscopy of macroscopic samples can be calibrated against reference analysis, such as lipid profiles acquired by gas chromatography, and serve as a fast, low-cost, quantitative analytical method. Calibration of infrared microspectroscopic images against reference data is in general not feasible, and thus spatially resolved quantitative analysis from infrared spectral data has not been possible so far. In this work, we present a deep learning-based calibration transfer method to adapt regression models established for macroscopic infrared spectroscopic data to apply to microscopic pixel spectra of hyperspectral IR images. The calibration transfer is accomplished by transferring microspectroscopic infrared spectra to the domain of macroscopic spectra, which enables the use of models obtained for bulk measurements. This allows us to perform quantitative chemical analysis in the imaging domain based on infrared microspectroscopic measurements. We validate the suggested microcalibration approach on microspectroscopic data of oleaginous filamentous fungi, which is calibrated toward lipid profiles obtained by gas chromatography and measurements of glucosamine content to perform quantitative infrared microspectroscopy.
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    Revealing the Potential of Lipid and beta-Glucans Coproduction in Basidiomycetes Yeast
    (MDPI, 2020-07-08) Byrtusová, Dana; Shapaval, Volha; Holub, Jiří; Šimanský, Samuel; Rapta, Marek; Szotkowski, Martin; Kohler, Achim; Márová, Ivana
    Beta (beta)-glucans are polysaccharides composed of D-glucose monomers. Nowadays, beta-glucans are gaining attention due to their attractive immunomodulatory biological activities, which can be utilized in pharmaceutical or food supplementation industries. Some carotenogenicBasidiomycetesyeasts, previously explored for lipid and carotenoid coproduction, could potentially coproduce a significant amount of beta-glucans. In the present study, we screened elevenBasidiomycetesfor the coproduction of lipids and beta-glucans. We examined the effect of four different C/N ratios and eight different osmolarity conditions on the coproduction of lipids and beta-glucans. A high-throughput screening approach employing microcultivation in microtiter plates, Fourier Transform Infrared (FTIR) spectroscopy and reference analysis was utilized in the study. Yeast strainsC. infirmominiatumCCY 17-18-4 andR. kratochvilovaeCCY 20-2-26 were identified as the best coproducers of lipids and beta-glucans. In addition,C. infirmominiatumCCY 17-18-4,R. kratochvilovaeCCY 20-2-26 andP. rhodozymaCCY 77-1-1 were identified as the best alternative producers of beta-glucans. Increased C/N ratio led to increased biomass, lipid and beta-glucans production for several yeast strains. Increased osmolarity had a negative effect on biomass and lipid production while the beta-glucan production was positively affected.
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    Porovnání metod úpravy vzorků pro stanovení makroprvků v mléce technikou ICP-OES
    (Slovenská poľnohospodárska univerzita v Nitre, 2020-05-25) Křikala, Jakub; Diviš, Pavel; Pořízka, Jaromír
    Cílem této metodologické studie bylo porovnat několik běžně používaných metod, jako je příprava disperze, solubilizace za použití činidel, mineralizace na mokré či suché cestě a mikrovlnná digesce pro úpravu vzorku před analýzou ICP-OES. Jako modelová mléčná matrice pro přípravu vzorků byl použit referenční materiál ERM® - BD150 s certifikovanými hodnotami sledovaných makroprvků (Ca, K. Mg, Na a P). Pomocí Karl-Fisherovy titrace byla v referenčním materiálu stanovena vlhkost 11,5 ± 2,3 %. Nejvyšší výtěžnosti pro Ca (94,9 ± 7,0 %) a Mg (113,7 ± 5,5 %) byly dosaženy za použití činidla Triton X-100, které podporuje solubilizaci mléčné matrice během sonikace. Nejvyšší výtěžnosti při stanovení K, Na a P (92,1 ± 3,0%, 105,9 ± 6,5% a 102,7 ± 1,2%) ) byly dosaženy při rozkladu vzorku na mokré cestě. Mineralizační metody vykazují taktéž dobrou přesnost, takže se jeví jako vhodné pro rutinní přípravu vzorku před analýzou, je však nezbytná další optimalizace úpravy vzorku, popř. pracovních parametrů přístroje, pro stanovení Ca a K v mléce.
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    A Comparative Study of Some Procedures for Isolation of Fruit DNA of Sufficient Quality for PCR-Based Assays
    (MDPI, 2020-09-25) Fialová, Lenka; Langová, Denisa; Márová, Ivana
    Food fraud has been and still is a problem in the food industry. It is detectable by several approaches, such as high performance liquid chromatography (HPLC), chemometric assays, or DNA-based techniques, each with its own drawbacks. This work addresses one major drawback of DNA-based methods, in particular their sensitivity to inhibitors contained in particular matrices from which DNA is isolated. We tested five commercial kits and one in-house method characterized by different ways of sample homogenization and DNA capture and purification. Using these methods, DNA was isolated from 10 different fruit species commonly used in plant-based foodstuffs. The quality of the DNA was evaluated by UV-VIS spectrophotometry. Two types of qPCR assays were used for DNA quality testing: (i) Method specific for plant ITS2 region, (ii) methods specific for individual fruit species. Based mainly on the results of real-time PCR assays, we were able to find two column-based kits and one magnetic carrier-based kit, which consistently provided fruit DNA isolates of sufficient quality for PCR-based assays useful for routine analysis and identification of individual fruit species in food products.
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    Recent Advances in 3D Printing of Polyhydroxyalkanoates: A Review
    (Sciendo, 2021-01-22) Kovalčík, Adriána
    In the 21st century, additive manufacturing technologies have gained in popularity mainly due to benefits such as rapid prototyping, faster small production runs, flexibility and space for innovations, non-complexity of the process and broad affordability. In order to meet diverse requirements that 3D models have to meet, it is necessary to develop new 3D printing technologies as well as processed materials. This review is focused on 3D printing technologies applicable for polyhydroxyalkanoates (PHAs). PHAs are thermoplastics regarded as a green alternative to petrochemical polymers. The 3D printing technologies presented as available for PHAs are selective laser sintering and fused deposition modeling. Stereolithography can also be applied provided that the molecular weight and functional end groups of the PHA are adjusted for photopolymerization. The chemical and physical properties primarily influence the processing of PHAs by 3D printing technologies. The intensive research for the fabrication of 3D objects based on PHA has been applied to fulfil criteria of rapid and customized prototyping mainly in the medical area.