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The content of antioxidants in raw materials and their stability in enriched foods depending on the processing technology
BEDRNÍČEK, Jan
Oxidation reactions, that can negatively affect safety and sensory properties, take place during food storage. To inhibit such an unwanted process, natural polyphenolic antioxidants can be added to food. The aim of this thesis was to study the effects of the addition of polyphenol rich plant materials on chemical and sensory properties of commonly consumed food products. Two types of polyphenol rich plant material were chosen: onion (Allium cepa L.) peel, which is processing by-product and rosemary (Rosmarinus officinalis L.) extract Inolens 4. The addition of polyphenol rich material (both, onion peel and rosemary extract) increased antioxidant activity of food and also delayed lipid oxidation in meat products. Unfortunately, in some cases the addition caused deterioration of sensory properties leading to poor consumers' acceptance. This was observed mainly after the addtition of onion peel powder in higher amounts. The addtition negatively affected hardness of texture. On the other hand, onion peel powder can effectively cover or reduce formation of unpleasant fishy odour, that is typical for fish products stored for long period of time. Additionally, several coumpounds occurring only in onion peel were identified (4 types of quercetin dimer and 1 type of trimer) and their stability during thermal treatment of fortified food was elucidated. This was first study that described this phenomenon. Overall, it can be concluded that plant polyphenols have the potential to extend shelf life of food products.
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Technology of production of fermented meat products
BEDRNÍČEK, Jan
The theme of this thesis is technology of production of fermented meat products and is focused on Lovecky salami. In the literature review, the work deals with the history, legislation, materials and technologies for the production of this group of meat products. There are also described methods of sensory analyse. Practical part dealt with: a) measuring of selected physical and chemical quantities (pH, water activity) during rippening and long-term storaging of Lovecky salami; b) influence of packaging method (unpacked, modified atmosphere, vacuum) on sensory value during long-term storaging. These results provide information about the ripening of Lovecky salami and cunsumer preferences in terms of packaging method. Experiment was cunducted in company MasoWest s.r.o. which starts with production of Lovecky salami.
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Influence of soil properties on mobility of selected risk elements in the soil and some methods of their decontamination
BEDRNÍČEK, Jan
Development of society and the increasing population of the planet are related to the increasing discharge of wastes and pollutants. These include heavy metals. Purpose of this bachelor´s thesis is to briefly clarify behaving of lead, cadmium and mercury in the soil; it means content, forms, mobility, sorption and its influencing factors and their impact on the animal and plant organism. This thesis also gives a wider view on the issue of decontamination techniques with focusing on bioremediation and mainly phytoremediation with the use of plant hyperaccumulators.
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