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Changes of antioxidants in selected fruits during long-term freezing
Štindlová, Jitka ; Lichnová, Andrea (referee) ; Márová, Ivana (advisor)
In this bachelor thesis some low molecular weight antioxidants contained in strawberries, raspberries, blueberries and cranberries are described. In the theoretical part also general characteristics of these fruits are introduced. Experimental part was focused on analysis of the changes of selected antioxidant content in the fruits. These changes were monitored during storage in two different conditions – in refrigerator and in freezer. In refrigerator whole fruits were stored for 8 days. The experiment in the freezer was performed for 2 months and the fruits were stored in four different processed forms – as a whole fruit, whole fruit impregnated by sucrose solution, as a pulp and pulp mixed with sucrose. Antioxidant content in fruits was analyzed by HPLC and spectrophotometry. The highest total content of antioxidants was found in strawberries, while the lowest values were found in raspberries. During storage some part of original antioxidant content stayed conserved, the highest content was preserved in blueberries processed as a whole fruits and impregnated whole fruits.
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The selected micronutrients and heavy metals in fruits
Formanová, Kristýna ; Diviš, Pavel (referee) ; Vránová, Dana (advisor)
Today is the food quality a discussed topic not only in the Czech Republic. In this work we focused on micronutrients and heavy metals in strawberries. Strawberries are very attractive fruit consumed by all age groups from children to seniors. These bring not only gustatory pleasure but also positive effects on human organism. Soft fruit structure could contribute to the accumulation of heavy metals, which can be dangerous in certain quantities in terms of acute toxicity or what is more likely in terms of chronic exposure. In the spring - autumn of 2011 samples from the home cultivation of strawberries in the Czech Republic were collected and also samples of fruits that are commonly available in supermarket chains in this period were purchased. The element analysis was performed by the mass spectrometry with inductively coupled plasma, which belongs to a very sensitive method of elements determination.
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Metody nanášení hydrogelů na povrch ovoce a zeleniny
Hrabová, Martina
The aim of this thesis was to develop a methodology for applying biopolymer mixtures directly onto the surface of selected fresh foods, fruits and vegetables, and to evaluate the prospects of biopolymer mixtures based on egg white. The theoretical part of this thesis outlines the issue of the packaging industry and the causes of food spoilage. Furthermore, methods for the application of biopolymeric coatings and films on a laboratory scale are described and natural polymers are summarized. In the experimental part of the thesis, the most suitable coating mixture was selected regarding the evaluation of strawberry and cucumber samples’ coating made of different biopolymeric mixtures. For this coating mixture, the samples of fruit and vegetable were subjected to analysis by near infrared spectroscopy.
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Mechanizace pro pěstování jahod a její vliv na kvalitu a výnos
BALOUN, Tomáš
The diploma thesis deals with production strawberries and mechanization means, which are used in the cultivation of this crop. The subject of this work is to find suitable mechanization means that are practically used in this activity and their description. The scope of work is also the monitoring of specific selected mechanization means in specific conditions of the agricultural enterprise and evaluation of their impact on the quality of work, yield and condition of the stand, as well as evaluation of their area performance and fuel consumption.
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The selected micronutrients and heavy metals in fruits
Formanová, Kristýna ; Diviš, Pavel (referee) ; Vránová, Dana (advisor)
Today is the food quality a discussed topic not only in the Czech Republic. In this work we focused on micronutrients and heavy metals in strawberries. Strawberries are very attractive fruit consumed by all age groups from children to seniors. These bring not only gustatory pleasure but also positive effects on human organism. Soft fruit structure could contribute to the accumulation of heavy metals, which can be dangerous in certain quantities in terms of acute toxicity or what is more likely in terms of chronic exposure. In the spring - autumn of 2011 samples from the home cultivation of strawberries in the Czech Republic were collected and also samples of fruits that are commonly available in supermarket chains in this period were purchased. The element analysis was performed by the mass spectrometry with inductively coupled plasma, which belongs to a very sensitive method of elements determination.
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|
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Changes of antioxidants in selected fruits during long-term freezing
Štindlová, Jitka ; Lichnová, Andrea (referee) ; Márová, Ivana (advisor)
In this bachelor thesis some low molecular weight antioxidants contained in strawberries, raspberries, blueberries and cranberries are described. In the theoretical part also general characteristics of these fruits are introduced. Experimental part was focused on analysis of the changes of selected antioxidant content in the fruits. These changes were monitored during storage in two different conditions – in refrigerator and in freezer. In refrigerator whole fruits were stored for 8 days. The experiment in the freezer was performed for 2 months and the fruits were stored in four different processed forms – as a whole fruit, whole fruit impregnated by sucrose solution, as a pulp and pulp mixed with sucrose. Antioxidant content in fruits was analyzed by HPLC and spectrophotometry. The highest total content of antioxidants was found in strawberries, while the lowest values were found in raspberries. During storage some part of original antioxidant content stayed conserved, the highest content was preserved in blueberries processed as a whole fruits and impregnated whole fruits.
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