Ústav chemie potravin a biotechnologií

Browse

Now showing 1 - 5 of 80

The study of relationship between taste and wheat bran protein isolate fortification during high-protein yogurt manufacturing
(ELSEVIER, 2024-05-03) Slavíková, Zuzana; Diviš, Pavel; Bialas, Wojciech; Montowska, Magdalena; Adamczyková, Michaela; Pořízka, Jaromír
High-protein (HP) food is becoming a popular and nutritionally valuable commodity. The most common protein fortifiers are milk whey or soy protein isolates. However, one of the potentially promising sources of quality protein isolate is wheat bran, the secondary product of wheat milling. Wheat bran protein isolate (WBPI) can be obtained using a sustainable and environmentally friendly pH shift method. Considering its nutritional properties, incorporating WBPI into people's diet is convenient. This work focuses on protein fortification of plain yogurt using WBPI while maintaining sensory acceptability. Direct fortification of yogurts with WBPI to achieve 5 % and 10 % protein content revealed two main sensory defects - bitterness and sandiness. Several approaches, such as grinding WBPI, protein blending, and WBPI encapsulation, were applied to improve the overall impression score of HP yogurts. It was found that eliminating the sandiness of WBPI-fortified yogurt is not possible by reducing WBPI particle size. Blending WBPI with dried milk decreased bitterness, but the products lacked amino acid diversity. The most effective procedure to mask the sensory defects was WBPI encapsulation using alginate, revealing an appropriate way to incorporate natural plant proteins into HP food.
G-quadruplex propensity in H. neanderthalensis, H. sapiens and Denisovans mitochondrial genomes
(Oxford University Press, 2024-05-30) Brázda, Václav; Šislerová, Lucie; Cucchiarini, Anne; Mergny, Jean-Louis
Current methods of processing archaeological samples combined with advances in sequencing methods lead to disclosure of a large part of H. neanderthalensis and Denisovans genetic information. It is hardly surprising that the genome variability between modern humans, Denisovans and H. neanderthalensis is relatively limited. Genomic studies may provide insight on the metabolism of extinct human species or lineages. Detailed analysis of G-quadruplex sequences in H. neanderthalensis and Denisovans mitochondrial DNA showed us interesting features. Relatively similar patterns in mitochondrial DNA are found compared to modern humans, with one notable exception for H. neanderthalensis. An interesting difference between H. neanderthalensis and H. sapiens corresponds to a motif found in the D-loop region of mtDNA, which is responsible for mitochondrial DNA replication. This area is directly responsible for the number of mitochondria and consequently for the efficient energy metabolism of cell. H. neanderthalensis harbor a long uninterrupted run of guanines in this region, which may cause problems for replication, in contrast with H. sapiens, for which this run is generally shorter and interrupted. One may propose that the predominant H. sapiens motif provided a selective advantage for modern humans regarding mtDNA replication and function.
The First Insight into Polyhydroxyalkanoates Accumulation in Multi-Extremophilic Rubrobacter xylanophilus and Rubrobacter spartanus
(MDPI, 2021-05-01) Kouřilová, Xenie; Schwarzerová, Jana; Buchtíková, Iva; Sedlář, Karel; Mrázová, Kateřina; Krzyžánek, Vladislav; Nebesářová, Jana; Obruča, Stanislav
Actinobacteria belonging to the genus Rubrobacter are known for their multi-extremophilic growth conditions-they are highly radiation-resistant, halotolerant, thermotolerant or even thermophilic. This work demonstrates that the members of the genus are capable of accumulating polyhydroxyalkanoates (PHA) since PHA-related genes are widely distributed among Rubrobacter spp. whose complete genome sequences are available in public databases. Interestingly, all Rubrobacter strains possess both class I and class III synthases (PhaC). We have experimentally investigated the PHA accumulation in two thermophilic species, R. xylanophilus and R. spartanus. The PHA content in both strains reached up to 50% of the cell dry mass, both bacteria were able to accumulate PHA consisting of 3-hydroxybutyrate and 3-hydroxyvalerate monomeric units, none other monomers were incorporated into the polymer chain. The capability of PHA accumulation likely contributes to the multi-extremophilic characteristics since it is known that PHA substantially enhances the stress robustness of bacteria. Hence, PHA can be considered as extremolytes enabling adaptation to extreme conditions. Furthermore, due to the high PHA content in biomass, a wide range of utilizable substrates, Gram-stain positivity, and thermophilic features, the Rubrobacter species, in particular Rubrobacter xylanophilus, could be also interesting candidates for industrial production of PHA within the concept of Next-Generation Industrial Biotechnology.
Stress Effect of Food Matrices on Viability of Probiotic Cells during Model Digestion
(MDPI, 2021-07-05) Skoumalová, Petra; Hoová, Julie; Ryšávka, Petr; Márová, Ivana
The aim of this study was to evaluate the influence of model (alcohol, sugar, salt, protein and acid) and real foods and beverages on the viability of probiotics during incubation and artificial digestion. Viability of monocultures Lactobacillus acidophilus CCM4833 and Bifidobacterium breve CCM7825T, and a commercial mixture of 9 probiotic bacterial strains, was tested by cultivation assay and flow cytometry. In model foods, the best viability was determined in the presence of 0.2 g/L glucose, 10% albumin and 10% ethanol. As the most suitable real food for probiotic survival, complex protein and carbohydrate substrates were found, such as beef broth, potato salad with pork, chicken with rice, chocolate spread, porridge and yoghurt. The best liquid was milk and meat broth, followed by Coca-Cola, beer and coffee. Viability of probiotics was higher when consumed with meals than with beverages only. Addition of prebiotics increased the viability of probiotics, especially in presence of instant and fast foods. Generally, the highest viability of probiotics during artificial digestion was observed in mixed culture in the presence of protein, sugar and fat, or their combination. The increase of cell viability observed in such foods during model digestion may further contribute to the positive effect of probiotics on human health.
Drug Release Kinetics of Electrospun PHB Meshes
(MDPI, 2019-06-14) Kundrát, Vojtěch; Černeková, Nicole; Kovalčík, Adriána; Enev, Vojtěch; Márová, Ivana
Microbial poly(3-hydroxybutyrate) (PHB) has several advantages including its biocompatibility and ability to degrade in vivo and in vitro without toxic substances. This paper investigates the feasibility of electrospun PHB meshes serving as drug delivery systems. The morphology of the electrospun samples was modified by varying the concentration of PHB in solution and the solvent composition. Scanning electron microscopy of the electrospun PHB scaffolds revealed the formation of different morphologies including porous, filamentous/beaded and fiber structures. Levofloxacin was used as the model drug for incorporation into PHB electrospun meshes. The entrapment efficiency was found to be dependent on the viscosity of the PHB solution used for electrospinning and ranged from 14.4–81.8%. The incorporation of levofloxacin in electrospun meshes was confirmed by Fourier-transform infrared spectroscopy and UV-VIS spectroscopy. The effect of the morphology of the electrospun meshes on the levofloxacin release profile was screened in vitro in phosphate-buffered saline solution. Depending upon the morphology, the electrospun meshes released about 14–20% of levofloxacin during the first 24 h. The percentage of drug released after 13 days increased up to 32.4% and was similar for all tested morphologies. The antimicrobial efficiency of all tested samples independent of the morphology, was confirmed by agar diffusion testing.

Browse

Recent Submissions