National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Chemical and sensory characterization of cider made from apple cultivars ordinarily grown in Czech republic
Strapcová, Zuzana ; Vítová, Eva (referee) ; Pořízka, Jaromír (advisor)
This master thesis deals with the investigation of selected chemical and sensory characteristics of ciders, which were made from four selected apple varieties. The theoretical part describes the chemical composition of apples, cider, the technology of production and production in the world. The next section describes the analytical methods used to determine chemical characteristics not only in ciders but also in other alcoholic beverages. The experimental part focuses on the determination of chemical characteristics such as the content of organic acids, carbohydrates, total phenolic content, alcohol antioxidant activity and elemental composition. The purpose of the work was to find out how different varieties differ in chemical composition. The produced ciders were subjected to sensory analysis to evaluate the selected cider sensory parameters, which were in the natural state and with the addition of carbon dioxide. The results show that ciders of different varieties differ in chemical composition. Malic acid was the most cider's abundant of the organic acids in the range of 2759 – 4411 mg·l-1. Another acid represented was lactic acid in the range of 166,2 – 288,1 mg·l-1. The glucose content of each cider was determined between 845,3 – 1159,8 mg·l-1and fructose 32,6 – 406,7 mg·l-1. Potassium 944,29 – 1073,98 mg·l-1 was the most represented of all elements. The total phenolic content was determined to be in the range of 164,2 – 214,1 mg of GAE·l-1and the antioxidant activity of 0,192 – 0,318 mg·l-1. These differences in chemical composition were also reflected in sensory evaluation. According to the overall assessment, the best cider was made from the Granny Smith variety, which contained the most organic acids and carbohydrates. It has been found that by adding carbon dioxide, sensory parameters such as colour, taste and smell are altered.
Determination of basic chemical characteristics of blueberry pulp
Strapcová, Zuzana ; Hrstka, Miroslav (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis deals with the investigation of selected chemical characteristics in the semifinished products of blueberries (Vaccinium myrtillus L.) and blueberries high (Vaccinium corymbosum L.). The theoretical part is described the botanical characteristics of both blueberries. The use of fruits is described in the next part. A description of the determination of the selected characteristic, refractometric of sugar dry mater, is described at the end of the theoretical part. In the experimental part, chemical characteristics were determined as total and soluble solids, pH, amount of titratable acids, reducing carbohydrates, phenolics and total anthocyanins in juice, pulp and extracts of blueberries. The purpose of the extracts was to find out how many total anthocyanins and phenolics are found in the skin of the fruit and which extract gives the highest yields. The results of the characteristics were compared across the wholefruit and semifinished products of the both blueberries. A mixture of water and ethanol in a ratio 50:50 was the most suitable solvent. The maximum extraction dependence was at twelfth and thirteenth hours of maceration. The maximum extraction dependence was determined by the above described chemical characteristics. Content of anthocyanin dyes expressed as delphinidin-3-glucoside was determined in extract of blueberry in 59,7 mg DGE100 g-1 and blueberries high in 19,6 mg DGE100 g-1. Total phenolics content expressed as gallic acid was determined in extract of blueberry in 890,9 mg GAE100 g-1 and blueberries high in 249,9 mg GAE100 g-1.

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