Ústav chemie potravin a biotechnologií
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- ItemRevealing 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, IvanaBeta (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.
- ItemPorovnání metod úpravy vzorků pro stanovení makroprvků v mléce technikou ICP-OES(Slovenská poľnohospodárska univerzita v Nitre, 2020-05-25) Křikala, Jakub; Diviš, Pavel; Pořízka, JaromírCílem 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.
- ItemA 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, IvanaFood 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.
- ItemRecent Advances in 3D Printing of Polyhydroxyalkanoates: A Review(Sciendo, 2021-01-22) Kovalčík, AdriánaIn 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.
- ItemSimultaneous determination of sweeteners and preservatives in beverages by HPLC-DAD-ELSD(HACCP Consulting, 2020-10-28) Diviš, Pavel; Jurečková, Zuzana; Vespalcová, Milena; Pořízka, Jaromír; Punčochářová, LenkaPeople suffering from diabetes or being overweight must severely reduce their sugar use, often seeking food with sweeteners. Often, sugar is replaced by non-nutritious sweeteners in beverages, which also contain several other substances like vitamins, caffeine, amino acids, phenolic compounds and thus increasing the shelf life of the beverages is additionally treated with the addition of preservatives. As the concentration of additives in food (including beverages) is determined by the legislation in force, it is necessary to have an appropriate analytical method for food control. Since artificial sweeteners and preservatives are very different substances, they are determined separately using different HPLC methods. In this work HPLC method combining the advantages of specific (diode array detector, DAD) and universal (evaporative light scattering detector, ELSD) detector was validated and used for simultaneous determination of benzoic acid, sorbic acid, aspartame, acesulfame K, saccharin, sucralose and steviol glycosides in sugar-free beverages. The proposed analytical method showed good linearity, precision, and accuracy. Measured limits of detection (0.6 – 11.8 mg.dm-3 depending on the analyte) were sufficient to analyze 5-times diluted beverage samples. The validated method has been successfully used for the simultaneous analysis of artificial sweeteners and preservatives in beverage samples (energy drinks, ice teas, carbonated drinks). Except for steviol glycosides, the concentration of monitored substances in beverages did not exceed the maximum permitted concentrations given in the valid legislation.