The usage of OECD tests for determination of waste ecotoxicity

Ve své bakalářské práci se zabývám testy ekotoxicity odpadů, které jsou doporučovány mezinárodní organizací OECD. Cílem práce je tyto testy charakterizovat a vzájemně je porovnat z hlediska jejich použití. Práce představuje mezinárodní organizaci OECD, její vznik a vztah k České republice. Dále je zde diskutována problematika odpadů. Jsou zde definovány základní pojmy této oblasti, druhy odpadů a zdroje jejich vzniku. Největší pozornost je věnována ekotoxikologickým testům, které jsou charakterizovány podle možného použití, provedení a testovacího organismu.In my bachelor thesis I consern myself with tests of waste ecotoxicity that are recommended by OECD. The main purpose of the thesis is to characterize these tests and compare them from the application aspect. The thesis presents OECD, its establishment and relation to the Czech Republic. Waste problems are discussed here too. Fundamental terms in this field, sorts of waste and its origin are defined here. The main attention is focused on ecotoxicological tests that are characterized according to their application, implementation and testing organism.

Evaluation of selected physicochemical parameters of extra virgin olive oil commercialized in the Czech market and stored during a period of 5 months

The scope of this work was to evaluate the development of selected physicochemical parameters (free acidity, peroxide value and specific extinction coefficients in ultraviolet) of extra virgin olive oil, commercialized in the Czech market and stored for a time period of 5 months (at 20 ±5 °C). The tested extra virgin olive oil samples were stored under conditions simulating domestic and commercial storage environment, in which the impact of light and headspace volume were also examined. Moreover, all the analyzed samples fell within the established "extra virgin olive oil category", thus proving their legitimacy, authentication and excellent quality. Furthermore, all the monitored physicochemical parameters were affected by the progress of the storage period, the rising volume of headspace (due to more available oxygen in the container) and exposition to light, resulting in decreasing quality of the examined extra virgin olive oil samples. In addition, the storage of extra virgin olive oil samples in dark containers reported sufficient resistance to oxidation processes up to a period of 3 months, however, after this period signs of oil quality deterioration were reported. Nevertheless, if exposition to light occurred, accelerated decrease in the quality of the extra virgin olive oil samples was observed. © 2017 Potravinarstvo Slovak Journal of Food Sciences, License

Evaluation of selected physicochemical parameters of extra virgin olive oil commercialized in the Czech market and stored during a period of 5 months

The scope of this work was to evaluate the development of selected physicochemical parameters (free acidity, peroxide value and specific extinction coefficients in ultraviolet) of extra virgin olive oil, commercialized in the Czech market and stored for a time period of 5 months (at 20 ±5 °C). The tested extra virgin olive oil samples were stored under conditions simulating domestic and commercial storage environment, in which the impact of light and headspace volume were also examined. Moreover, all the analyzed samples fell within the established "extra virgin olive oil category", thus proving their legitimacy, authentication and excellent quality. Furthermore, all the monitored physicochemical parameters were affected by the progress of the storage period, the rising volume of headspace (due to more available oxygen in the container) and exposition to light, resulting in decreasing quality of the examined extra virgin olive oil samples. In addition, the storage of extra virgin olive oil samples in dark containers reported sufficient resistance to oxidation processes up to a period of 3 months, however, after this period signs of oil quality deterioration were reported. Nevertheless, if exposition to light occurred, accelerated decrease in the quality of the extra virgin olive oil samples was observed

Free and bound amino acids, minerals and trace elements in matcha (Camellia sinensis L.): A nutritional evaluation

This study provides an overview of free and bound amino acids, minerals and trace elements content in matcha including evaluation of their dietary intakes. The analyses employed IEC and ICP-MS methods. Theanine followed by Glu, GABA, Thr and Me were the most abundant free amino acids. Considering bound amino acids, Glu, Asp, Leu, Lys, Arg and Val were the most frequent. The amino acid score (AAS) for matcha (40.2 %) is comparable to the AAS for wheat and sunflower proteins. Ile and Thr were evaluated as limiting amino acids. Regarding recommended daily allowance (RDA), the contributions of Cys and Met were up to 8%. Matcha is contributor to Adequate Intake (AI) or RDA for males in the following order: Mn (up to 15 %) > Cu > Fe (up to 7%). Similarly, for females, matcha contributes to RDA or AI values in this order: Mn (up to 19 %) > Cu > Zn (up to 5%). It has not been proved that matcha is a significant source of Se and Cr. A daily serving portion of 5 g does not contribute to PTWI (Provisional tolerable weekly intake) and PTMI (Provisional tolerable monthly intake) for Al, Sn, Cd and Hg. © 2020 Elsevier Inc

The effect of homogenization and addition of polysaccharides on the viscoelastic properties of processed cheese sauce

This study was conducted to determine the effect of 1-stage homogenization (OSH) and 2-stage homogenization (TSH) and the addition of polysaclevels ranging from 0.000 to 1.000% (wt/wt)] on the physicochemical, viscoelastic, and mechanical vibration damping properties of processed cheese sauces (PCS) after 30 d of storage (6 +/- 2 degrees C). The basic chemical all tested samples. Viscoelastic measurements indicated that PCS rigidity was directly proportional to increasing CR or FR concentration and to the application of homogenization. The interactions between the application of homogenization and the concentration of polysaccharides used were also significant. Compared with OSH, TSH did not lead to any further increase in the rigidity. The preceding results were also supported by data obtained from a nondestructive method of mechanical vibration damping. No changes in water activity were observed in any PCS sample. Overall, the addition of FR or CR appeared to be highly suitable for increasing the emulsion stability of PCS. If PCS products with softer consistency are desired, then a concentration of CR/FR 1.000% (wt/wt) together was observed.QK1710156; Univerzita Tomáše Bati ve Zlíně: IGA/FT/2022/005National Agency for Agriculture Research [QK1710156]; Grant Agency of the Tomas Bata University [IGA/FT/2022/005

Spectroscopic analysis of milk fat and its mathematical evaluation

The aim of this paper is to verify the applicability of Raman spectroscopy for measuring the content of fat in milk and dairy products. Accurate monitoring of milk nutritional compositions is essential for producers of milk and also for milk and dairy products quality control. Raman spectroscopy enables effective material identification and offers rapid, non-contact, nondestructive, reagent free measurements and possibility to insert devices for automatization. These are the main benefits of this method comparing to traditional time-consuming techniques. The statistical method Principal component analysis was performed for large spectral datasets evaluation. For specific spectral information was used linear regression. Liquid milk samples as well as dried milk droplets with fat concentration range 0,1 % to 3,5 % and dairy products with 10 % and 82 % fat concentration were used for analyses by Raman spectroscopy. Röse-Gottlieb gravimetric method and butyrometric method served as a standard control methods for correlation with experimental spectroscopic data for milk fat analysis. Methods accuracy is discussed in the paper. Quite high agreement is obtained for Raman spectroscopy. © 2016 North Atlantic University Union NAUN. All rights reserved

Biogenic amines content in selected commercial fermented products of animal origin

The aim of this study was to monitor of biogenic amines contents in commercial fermented products, especially various type of ripening cheeses and fermented meat products (15 cheese samples and nine dry fermented meat products obtained from Czech Republic, Slovak Republic, Poland, and Germany). Furthermore, the changes in samples during storage were also observed. The samples were stored at 6 +/- 1 degrees C. The samples were taken the first day of storage and the last day of shelf-life. The biogenic amines content was determined using ion-exchange liquid chromatography with post-column derivatization and photometric detection. The content of biogenic amines increased during storage. The highest biogenic amines content at the end of storage was observed in Dutch-type cheeses and in Smear cheeses, in both the concentrations exceeded 1 000 mg. kg(-1). Latter mentioned amount may have serious negative impact on consumer health. The lowest concentration of biogenic amines was detected in Blue cheese.Tomas Bata University in Zlin [IGA/FT/2012/027]; GACRGrant Agency of the Czech Republic [503/11/1417

Biofilm formation reduction by eugenol and thymol on biodegradable food packaging material

Biofilm is a structured community of microorganisms adhering to surfaces of various polymeric materials used in food packaging. Microbes in the biofilm may affect food quality. However, the presence of biofilm can ensure biodegradation of discarded packaging. This work aims to evaluate a biofilm formation on the selected biodegradable polymer films: poly (lactic acid) (PLA), poly (butylene adipate-co-terephthalate) (PBAT), and poly (butylene succinate) (PBS) by selected bacterial strains; collection strains of Escherichia coli, Staphylococcus aureus; and Bacillus pumilus, Bacillus subtilis, Bacillus tequilensis, and Stenotrophomonas maltophilia isolated from dairy products. Three different methods for biofilm evaluation were performed: the Christensen method, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and fluorescence microscopy. High biofilm formation was confirmed on the control PBS film, whereas low biofilm formation ability was observed on the PLA polymer sample. Furthermore, the films with incorporated antimicrobial compounds (thymol or eugenol) were also prepared. Antimicrobial activity and also reduction in biofilm formation on enriched polymer films were determined. Therefore, they were all proved to be antimicrobial and effective in reducing biofilm formation. These films can be used to prepare novel active food packaging for the dairy industry to prevent biofilm formation and enhance food quality and safety in the future. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.IGA/FT/2021/00

Furcellaran as a substitute for emulsifying salts in processed cheese spread and the resultant storage changes

The viscoelastic properties of processed cheese spread (PCS; dry matter 40% w/w, fat in dry matter 55% w/w) produced with various levels (0.10, 0.25, 0.50, 0.75 and 1.00% w/w) of two types of furcellaran (FA or FB), with and without the use of emulsifying salts (ES), were evaluated. The incremental higher levels of furcellaran application, irrespective of its type, increased the values of viscoelastic moduli. Processed cheese spread samples produced without the addition of ES showed higher rigidity. The type and concentration of furcellaran, the presence/absence of ES and storage time had a significant effect on the viscoelastic properties of PCS.internal grant agency of the Tomas Bata University in Zlin, Czech Republic [IGA/FT/2022/005

Biofilm Formation Reduction by Eugenol and Thymol on Biodegradable Food Packaging Material

Biofilm is a structured community of microorganisms adhering to surfaces of various polymeric materials used in food packaging. Microbes in the biofilm may affect food quality. However, the presence of biofilm can ensure biodegradation of discarded packaging. This work aims to evaluate a biofilm formation on the selected biodegradable polymer films: poly (lactic acid) (PLA), poly (butylene adipate-co-terephthalate) (PBAT), and poly (butylene succinate) (PBS) by selected bacterial strains; collection strains of Escherichiacoli, Staphylococcusaureus; and Bacillus pumilus, Bacillussubtilis, Bacillustequilensis, and Stenotrophomonasmaltophilia isolated from dairy products. Three different methods for biofilm evaluation were performed: the Christensen method, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and fluorescence microscopy. High biofilm formation was confirmed on the control PBS film, whereas low biofilm formation ability was observed on the PLA polymer sample. Furthermore, the films with incorporated antimicrobial compounds (thymol or eugenol) were also prepared. Antimicrobial activity and also reduction in biofilm formation on enriched polymer films were determined. Therefore, they were all proved to be antimicrobial and effective in reducing biofilm formation. These films can be used to prepare novel active food packaging for the dairy industry to prevent biofilm formation and enhance food quality and safety in the future