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Amount of selected biologically active compounds in Stevia rebaudiana
Porubčanová, Vladimíra ; Jurečková, Zuzana (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis deals with plant, called stevia rebaudiana and analysis of phenolic compounds in the extracts from it. The theoretical part describes its botanical characteristics, chemical constitution and effect on humans health. This thesis is interested in sweetener, produced from stevia, comercionally used as E 960: steviol-glykosides, too. There is listed register of companies producing this sweetener and food products, where stevia is used in. The experimental part of thesis is focused to analysis of total phenolic content in stevia extracts, because leaves of stevia are primary used for sweetening of tea. The main aim of the thesis was find out, how is total phenolic content changed during extraction of leaves in time, in water with different temperature and in different samples.
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Technologie pěstování Stévie sladké (Stevia rebaudiana) ve vztahu ke kvalitě produktu a jeho využití v potravinářství, medicíně a kosmetice.
KÁBELOVÁ, Lenka
The theoretical part of the diploma thesis deals with cultivation of the plant Stevia rebaudiana. This plant is 300x sweeter than sucrose. It is often used as a compensation for sugar sweetener, suitable for diabetics and people who suffer from overweight. There is processed the characteristics of the plant, botanical description, conditions of cultivation and chemical composition. There are described the methods of determination of steviol glycosides. The practical part elaborates on a sensorical analysis. This analysis has two parts. The first part is the evaluation of stevia concentrates with the flavour of aronia, sour cherry and beetroot and stevia powder in 10 milk products bought in supermarkets. The second part deals with the evaluation of black tea sweetened with few different easily available sorts of sweetening products. The currently valid legislative in the area of the Czech Republic allows the food industry to use steviol glycosides of high purity under the name E960. The use of the plant stevia or its parts as food isn't enabled.
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Effect of used sweeteners on sensory properties of fruit drinks
PRAYER, Radek
The object of the study was a sensory evaluation of used sweetners in beverages from selected fruits. Within the sensory analysis apple juice and also pear, apricot, cherry and blackcurrant nectar were used. These drinks were subsequently diluted at two concentrations with drinking water: 1) in a ratio of 50 % of the original beverage and 50 % of drinking water; 2) in a ratio of 25 % of the original beverage and 75% of drinking water. Each of the concentrations were then divided into groups which were sweetened with white sugar, cane sugar, aspartame, sucralose or rebaudioside A. The performed sensory analyses show that rebaudioside A would have great potential to replace the commonly used white sugar in apple juice. Sucralose would have this potential in pear and cherry drinks. However, the use of other sweeteners in other types of beverages is also not excluded, because to prove a preference for white sugar failed in most cases.
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Amount of selected biologically active compounds in Stevia rebaudiana
Porubčanová, Vladimíra ; Jurečková, Zuzana (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis deals with plant, called stevia rebaudiana and analysis of phenolic compounds in the extracts from it. The theoretical part describes its botanical characteristics, chemical constitution and effect on humans health. This thesis is interested in sweetener, produced from stevia, comercionally used as E 960: steviol-glykosides, too. There is listed register of companies producing this sweetener and food products, where stevia is used in. The experimental part of thesis is focused to analysis of total phenolic content in stevia extracts, because leaves of stevia are primary used for sweetening of tea. The main aim of the thesis was find out, how is total phenolic content changed during extraction of leaves in time, in water with different temperature and in different samples.
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The Technology of cultivation and fertilization sweet stevia (Stevia rebaudiana) and its use
KÁBELOVÁ, Lenka
This bachelor thesis is focused on growing Stevia rebaudiana Bertoni. It is a plant that is 300 times sweeter than sucrose. It is used as a compensation for ordinary sugar beet, as a low-calorie sweetener that is suitable for diabetics and people who are overweight. The botanical description and the chemical composition is compiled, and a sweetener from Stevia labeled as E960 steviosid is introduced. The whole phenological growth of Stevia at home conditions is photo-documented. Stevia is used in many fields. Mostly it is used as a sweetener in dried or fresh state and often in liquid extract form, too. It is also used in medicine to treat injuries because of its antibacterial effects. It has positive influence on treating herpes and mouth ulcers, and it prevents from bad breath. Nowadays, it is more and more used and it is becoming a favourite dietary supplement.
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