This thesis is concerned with biologically active substances in honey. The first part describes the characteristics of honey, its origin and its composition. It also deals with the polyphenols and importance of honey on human health. Polyphenols are the subject of many studies and was therefore chosen as representatives of the major biologically active substances. It describes their characteristics and representations of honey. The second part deals with the determination of polyphenols. For this purpose were selected 14 phenolic acids, which was determined in 8 kinds of honey. Analysis was performed by liquid chromatography mass spectrometry (HPLC-MS). Extraction was carried out by extraction by liquid-liquid and solid-phase extraction using two solvents, diethylether and ethylacetate. These methods were then statistically compared. The results show that the highest average content of phenolic acids was in honey pine honeydew and honeydew mixed. Generally, honeys contain most p-coumaric acid.

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In this diploma thesis, we focused on the filtration of wine, the type of filtration and the filtration methods currently used in the literary section. Further, filtration materials, which are used in wine filtration and, last but not least, the use of nanoparticles in viticulture and winemaking, have been described. In the practical part, commercial filter types were used, namely Cartridge filter C11 with nanofibrous filter membrane RIFTELEN N15-2 and RIFTELEN N15-5, which we compared with the Zambelli plate filter, in which we used filter plates HOBRAFILT S15N and HOBRAFILT S30N. In particular, we compared the content of free and total sulfur dioxide, wine turbidity, protein turbidity and polyphenols in wine. From each type of unfiltered and filtered wine, we put the samples in bottles of 750 ml and left overnight in the cellar. The next day we analytically measured each variant sample. All results were then statistically processed and evaluated with recommendations for practice and further investigation.

Unlike majority of sorts of alcoholic drinks beer is considered significantly un-stable. This thesis examines the factors influencing the stability of beer, especially phys-ical-chemical, primarily content of polyphenols and potential of components of beer to form haze. Twenty eight samples from differently large breweries were processed (Černá Hora, Poutník Pelhřimov, Pegas, Richard and minibrewery of Mendel University in Brno). The total content of polyphenols was determined using the Folin-Ciocalteu method (spectrophotometrically at 750 nm) and subsequently expressed in the content of ferulic acid, which served as a standard for purposes of this study. The average con-tent of polyphenols was in Černá Hora Sklepní 338,5 mg.l-1, in light lager beer Poutník 370 mg.l-1, in light lager beer Pegas 694,5 mg.l-1, in light lager beer Richard 726,3 mg.l-1, in wheat beer from Mendel University in Brno 562 mg.l-1 and in Rauch from Mendel University in Brno 817 mg.l-1. Turbidity of beer for consumption and potential of beer components to form haze using EBC test was also assessed. Both types of turbidity were measured by turbi-dimeter at 620 nm using Helm BaSO4 standard and based on the measured values were compared with the established range of haze. Finally, the results were discussed and assessed physical-chemical stability of observed beers.

This thesis was prepared at the Institute of Post-Harvest Technologies of Horticulture at the Faculty of Horticulture of the Mendel University in Brno in years 2012/2014. The aim of this thesis was to elaborate on the nutritional constitution of wines with emphasis on phenolic components, to deal with methods of determination of the antioxidant activity and to compile the legislative requirements relevant to selected wines. In the experimental part, wine-based beverages with the addition of wood chips or their extracts were designed and prepared. Subsequently, selected quality parameters of the prepared beverages were compared and the prospects of their success in the market place were evaluated.

The objective of this thesis was to investigate the content of polyphenols in these juices: apple from concentrate, apple produced by direct compression, orange with pulp, orange without pulp, grapefruit from concentrate, juice from red grapes, pomegranate and purple carrots. The measurement was taken by high performance liquid chromatography and mass spectrometry. The polyphenol with the highest overall value and also the most important of polyphenols in citrus juices was hesperidin. Significant content of cryptochlorogenic acid and hyperoside was in apple juice. Apple juice produced by direct compression also contained a lot of catechin. Epigallocatechin, epicatechin and gallic acid were substances with the highest value measured in the juice of the pomegranate. Catechin, epicatechin and epigallocatechin were most prevalent in the grape juice. Quantitatively the most important compounds of juice from purple carrots were caffeic and cryptochlorogenic acid.

The thesis entitled Screening of Polyphenols in Coffee deals with origins and attri-butes of particular types and technologies of coffee making.The theoretical section focuses on occurance and importance of biologically active compounds contained in coffee that might have both positive and negative impact on human´s health. I also mention the legislation related to the issue of defining and labeling the coffee. Regarding the most current lifestyle diseases and various social groups I describe the general influence of coffee on human´s health and the most common methods of determination polyphenols in food.In the practical part I use the High-performance liquid chromatography to identify the spectrum and amount polyphenolic com-pounds at selected samples of coffee of various geographical origin. Overall I tested samples of 10 roasted and 8 unroasted Arabica coffee and 2 samples of Robusta coffee.

There were analyzed the amount of caffeine, amounts of polyphenols, color, sensory properties and the spectra were measured using near infrared spectroscopy in three kinds of coffee. Analyses were made after roasting coffees. The coffee was then packaged into three different types of packaging - paper, package with one-way valve and into a vakuum package, each series of samples were stored in three different conditions - normal conditions (20 °C, 40% RH), a fridge (4-6 °C, 80% RH) and variable conditions (15-30 °C, 40-60% RH). After three, six and nine months was then carried out analyses for all samples. Subsequently the differences between the baseline sample and the results in different time were evaluated and the results were compared. It was found out that coffee quality sharply decreased after three months, caffeine over time decreased slightly. Sum of polyphenols sharply decreasesd after 3 months and their value was at a similar level. The color of the coffee changed after 3 and 6 months rapidly, but then the colour approached the original surface.