No description available.

No description available.

No description available.

The diploma thesis focuses on the content of biogenic amines (BA: tyramine, histamine, kadaverine, tryptamine, phenylethylamine) and polyamines (PA: putrescine, spermine, spermidine) in eidam, emmental and parmesan cheese. The theoretical part describes the origin, occurrence and importance of BA and PA, and the various factors influencing their occurrence. In the practical part, the influence of the type of cheese, temperature and storage time on the content of individual amines was monitored. The most significant amines in all types of tested cheeses were tyramine (eidam 173,3 mg/kg > emmental 4,4 mg/kg = parmesan 10,9 mg/kg) and putrescine (eidam 188,4 mg/kg > emmental 77,5 mg/kg = parmesan 36,4 mg/kg). When compared to all types of monitored cheeses stored for 3 weeks, there was a tendency (p > 0,05) to increase the BA content and decrease the PA content in the cheeses stored at 20 °C compared to the cheese stored at 5 °C (tyramine 128,1 mg/kg vs. 62,9 mg/kg, putrescine 61 mg/kg vs. 100,8 mg/kg). During storage (X, weeks), the tyramine content (Y; mg/kg) in eidam and emmental was increased by the following equation: y = 82,2 + 28,9x (R2 = 0,34, p = 0,005) and y = -10,7 + 5,17x (R2 = 0,23, p = 0,025). The corresponding regression for the content of PUT (on the other hand, the reduction of content) in emmental and parmesan was as follows: y = 230,1 – 63,63x + 4.249x2 (R2 = 0,92, p < 0,001) and y = 48,6 – 6,07x2 (R2 = 0,24, p = 0,024).

This thesis examined the effects of different cooking methods (boiling, stewing and roasting) on chicken liver in order to measure changes in the levels of biogenic amines (BA) and polyamines (PA). Two other factors were also considered, season and method of chicken liver storage. BA and PA levels were determined using a liquid chromatography method (UPLC). The mean level of BA in the original raw material (six and three samples of refrigerated and frozen livers, respectively) was very low, with the highest being histamine (4,11 mg.kg-1). Tryptamine and fenylethylamin were not detected in any of the samples. The level of PA was significantly higher than the level of BA, with more spermine (135 mg.kg-1) than spermidine (42,3 mg.kg-1). The total content of BA and PA in the dry matter of refrigerated livers was almost twice as high in the summer than in the winter (P < 0,001). When comparing refrigerated against frozen livers, the levels of putrescine and histamine were significantly higher in the refrigerated liver (P < 0,01), while the levels of cadaverine and tyramine were higher in the frozen liver (P < 0,001), and the levels of spermine and spermidine were 20 % lower in the frozen liver (P < 0,01). Roasting had less of an effect in the decline of BA (80 % of the original content) than cooking (65 % of the original content) (P < 0,001). The lowest levels of spermine and spermidine were found in the roasted liver (70 % of the initial content) while stewing and cooking caused a decrease of approximately 80 % (P < 0,01).

No description available.

No description available.

The thesis deals with verification of applicability of biogenic binders during casting of gray cast iron. Applicability of these binders for making moulds as well as cores was verificated. The introduction describes strength of cured mixture with biogenic binder including influence of additives and refractory coating. The main part describes process of manufacturing of castings being poured into the biogenic binder bonded moulds. Pouring castings with cores bonded with the same binder is described as well. The last part deals with assessment of the given tests. The thesis comprises photodocumentation of poured samples.

The aim of this thesis was to determine the content of biogenic amines and polyamines, specifically putrescine (PUT), spermidine (SPD) and spermine (SPM) in mutton meat during storage and heat treatment. The meat of slaughter animals is rich in these amines but, unfortunately, data on the content of mutton meat whether in slaughter bodies as well as during storage or heat treatments in the literature are still missing. The samples were provided by small farmers and the animals were hybrids of several breeds. The samples were taken from the thigh and back. The samples of lamb meat were frozen and the ones were watched from 0-6 months. The samples of leg were cooled and packed into three different types of packaging. It was the type of packaging in a polyethylene bag (PE), vacuum packed (VP) and controlled atmosphere packaging (MAP). All the samples were analyzed in the days and also on the initial concentration at day 0. For frozen and cooled (chilled) samples which were stored in PE and VP was observed the decrease in all monitored amines. Only the packaging in MAP occurred in the SPD to a slight increase over the initial content. From heat treatments were performed usual preparations of the meals which are made in central Europe and the meals were cooked on particular days. The highest decrease was measured in roasted meat, then stewed and cooked meat in this order. Reported data are comparable to published data for pork and beef meat stored under the same or similar conditions. I think that these data can help to extend the data in the literature.

The diploma thesis deals with the influence of spontaneous and controlled technology on the creation of biogenic amines. In the literary part, it deals with the properties, origin and their occurrence. It further describes the various factors and microorganisms that influence their creation. Consequently, it focuses on the effect of biogenic amines on health and factors that may increase their toxicity in the microorganism. At the end of the literature search, describe focuses on the creation of biogenic amines in wine, their content in world wines and focuses on oenological factors affecting their content. The experimental part describes the Chardonnay experiment procedure in detail. It was divided into four variants. Two of them were technologically processed in the barrel, the other two in a glass container. Subsequently, both versions in the barrel and in the glass were divided into a production process processed by spontaneous and controlled technology. Samples were sampled during the experiment and then analyzed analytically by HPLC for the formation of biogenic amines. The resulting wines were sensory evaluated. All results were statistically processed and compared with studies dealing with similar issues.