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Plant-derived food preservatives as alternatives to sulfites
Kmeťová, Martina ; Leuner, Olga (advisor) ; Melnikovová, Ingrid (referee)
In present, fresh-cut foods, dried fruits and processed vegetables are often treated with sulfites against the spoilage and enzymatic browning. However, these additives cause undesirable health risks at a certain portion of the population. In addition, customers demand food without added chemicals. This Bachelor thesis is a literature review of substances with similar properties such as sulfites. These substances should have the ability to inhibit browning and undesirable microorganisms and act as antioxidants; substances of natural origin without health risks unchanging organoleptic properties of food and at the same time available for price allowing them to participate in tests on food models. As a result, sixteen compounds which exhibit very similar properties as sulfites were suggested for further research.
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Traditional Methods of Fish Preservation in Southeast Asia
Holmanová, Kateřina ; Banout, Jan (advisor) ; Leuner, Olga (referee)
Traditional methods of fish preservation are still often used in developing countries, which produce significant amount of fresh fish. The most frequently used methods of processing fish in Cambodia are drying, salting, fermentation, smoking and marinating. Sun drying as one of the most common methods of fish processing in Cambodia has some disadvantages, which increase spoilage of final product. Salting contributes to increase efficiency of drying process. Salt creates highly salty environment, which the most bacteria, fungi and other potentially pathogenic organism cannot survive in. The aim of this Bachelors thesis was to carry out research focused on drying method in combination with salting. For five selected spices of freshwater fish: Claris batrachus, Channa micropeltes, Oreochromis niloticus, Pangasius hypophthalmus and Monopterus albus were determined dry matter content, fat content and salting effect on the amount of salt. Samples, before drying in direct solar dryer with natural convection and electric oven, were salted for 2, 4 and 12 hours. Results of measuring of dry matter content are within the interval 16.67 to 21.74 g on 100 g of fresh muscle, the lowest values were measured at C. batrachus and the highest at O. niloticus. Measuring of fat content showed difference in the interval 2.29 - 30.08 %, the lowest value at M. albus and highest at P. hypophthalmus. From the measurements of amount of salt were found influence of the salting time on the total amount of salt. Values increased with the higher time of salting. An important prerequisite for achieving high-quality dried products is characteristic properties for individual fish species to achieve maximum yield.
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