This diploma thesis Rheological properties of plain yoghurts with various fat content is aimed in its theoretical part on the basic summary of fermented milk products. It is focused mainly on yoghurts, especially plain yoghurts. The manufacture, composition, nutritional and health benefits, storage and shelf-life of yogurts is described. In the next chapter are described rheological properties of foods. The aim of the practical part is to assess rheological properties of plain yoghurt with various fat content. All samples are commonly available in the Czech shops. The range of fat content was 0,1–10,2 g/100 g. The dependency of shear stress on shear rate was studied as well as the dependency of apparent viscosity on shear rate (1,02–68 s-1). The rheological properties were fitted to Ostwald-de Waele model (the Power law). It was assessed that yoghurt is a Non-Newtonian fluid with shear thinning behaviour. Determination coefficients achieved high values (0,8748–0,9905). Time dependency and effect of various temperature (4 °C, 12 °C and 22 °C) on apparent viscosity was assessed. pH, titrable acidity, fat content and dry matter content were observed for all samples.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:427187 |
| Date | January 2018 |
| Creators | Synková, Lucie |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/masterThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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