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Preparation and characterization of microcrystalline cellulose from food waste
Horáková, Natálie ; Němcová, Andrea (referee) ; Kovalčík, Adriána (advisor)
The aim of the diploma thesis was to isolate microcrystalline cellulose from grape pomace. The analysis of grape pomace showed the following main components: lignin (32.9%), cellulose (34.2%), hemicellulose (31.5%) and lipids (7.0%). Various methods have been tested for the isolation and purification of microcrystalline cellulose. As the most suitable method was selected acid hydrolysis with 50 % and 64 % sulfuric acid followed by treatment with ethylenediamine. The morphology of the isolated cellulose was studied by transmission electron microscopy. The diameter of the hydrolyzed cellulose fibers was determined in the range of 15–130 nm. The isolated cellulose was used as reinforcing filler for agar. The agar/cellulose films were prepared by solution casting. The agar/cellulose films exhibited higher values of Young´s moduli and tensile strength but lower elongation at break compared to neat agar films. The results proved that grape pomace can be used as source for the isolation of microcrystalline cellulose with reinforcing ability for agar.
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Současné poznání v chovu matek a postupy vhodné k precizaci
Horáková, Natálie
The bachelor thesis deals with the breeding of queens, which means not only their own breeding, but also their insemination, adding and exchange. The aim of the bachelor thesis was to describe the current knowledge in queen breeding. The method of preparation of the bachelor thesis is a literature search of available literature sources on the subject. The thesis describes the practices of queen rearing, divided into natural and controlled rearing. The individual chapters deal with the following topics: bee breeding and developmental stages of the bee, the queen, her development and reproductive tract, drones, their rearing and cryopreservation of semen. The discussion and conclusion summarised all the knowledge gained and mentioned unfinished procedures in certain parts of queen rearing.
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Preparation and characterization of microcrystalline cellulose from food waste
Horáková, Natálie ; Němcová, Andrea (referee) ; Kovalčík, Adriána (advisor)
The aim of the diploma thesis was to isolate microcrystalline cellulose from grape pomace. The analysis of grape pomace showed the following main components: lignin (32.9%), cellulose (34.2%), hemicellulose (31.5%) and lipids (7.0%). Various methods have been tested for the isolation and purification of microcrystalline cellulose. As the most suitable method was selected acid hydrolysis with 50 % and 64 % sulfuric acid followed by treatment with ethylenediamine. The morphology of the isolated cellulose was studied by transmission electron microscopy. The diameter of the hydrolyzed cellulose fibers was determined in the range of 15–130 nm. The isolated cellulose was used as reinforcing filler for agar. The agar/cellulose films were prepared by solution casting. The agar/cellulose films exhibited higher values of Young´s moduli and tensile strength but lower elongation at break compared to neat agar films. The results proved that grape pomace can be used as source for the isolation of microcrystalline cellulose with reinforcing ability for agar.
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