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Influence of Storage Conditions on Metabolic Profile of Apples
Duroňová, Kateřina ; Vávrová, Milada (referee) ; Kráčmar, Stanislav (referee) ; Márová, Ivana (advisor)
The goal of presented dissertation has been complex analysis of changes in content of fatty acids, enzymatic and low-molecular antioxidants in apples and related evaluation of perception of originators of storage diseases for apples stored in various conditions. Main part of the work has been dedicated to study of the impact of storage of apples in modified atmosphere with reduced amount of oxygen and in reference “normal” atmosphere for six months. Next part of the work has been dedicated to study how apple storage in common, consumer affordable, conditions (storage in a cellar, in a refrigerator, and in room temperature) affects content of low-molecular antioxidants. For testing has been selected apple kinds Jonagored, Golden Delicious, Idared, Šampion, and Granny Smith. Within the scope of this work has been optimized the method for determination of fatty acids in plant material with higher content of wax. The measured values imply the apples are valuable source of many important nutrition substances like vitamins, provitamins and antioxidants. During the storage process these substances exhibit considerable protective function. Long-term storage, mainly in the atmosphere with reduced amount of oxygen (FAN), enables preservation of majority of these important nutrition substances depending on the kind of apple and conditions of storage. Freezing process is conservative to apples (mainly in the presence of protective substances), while in the process of drying the values of all monitored antioxidants decrease depending on temperature and conditions of drying. Upon the choice of the storage method one must consider nutrition, sensoric characteristic and consumer demands.
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Changes in selected local fruits during freezing.
Matějková, Markéta ; Melounová, Jitka (referee) ; Márová, Ivana (advisor)
This diploma thesis was focused on study of low-molecular antioxidants present in various kinds of fruits, namely berries. In theoretical part detailed characterization of antioxidants studied in presented work and their biological effects are introduced. Further, principals of processing and storage of specified species of fruits are discussed. Changes observed during storage of specific fruits are described too. In practical part changes in content of selected antioxidants in berries were followed. As studied material strawberries, raspberries, blueberries, red and black currants were used. All kind of these fruits was stored in fridge for six months using several different kind of processing. Berries were stored as whole fruits, whole osmotically processed fruits by sucrose, raw pulp and sweetened pulp. At first, starting values of selected antioxidant parameters were measured in fresh fruits (ascorbate, total antioxidant activity, total phenolics, catechins and individual flavonoids). After freezing the same parameters were measured regularly in two month periods. As the most suitable method of fruit processing, with regard to antioxidant content, storage of the whole fruits or pulp can be recommended. Content of ascorbate decreased in all forms and species of the processed fruits during all the time of storage. Oppositely, the content of other studied antioxidants exhibited fluctuations or increasing trend. Sensory analysis was proved for the whole fruits and also for whole sweetened fruits.
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Changes of enzyme activities in fruits during long-term storage
Ferdová, Jitka ; Melounová,, Jitka (referee) ; Márová, Ivana (advisor)
This study is focused on study of changes of enzyme and low-molecular weight antioxidants in different fruits during long-term storage. In theoretical part individual low-molecular weight antioxidants and enzymes are described. The main causes of fruit decay and some possibilities of fruit preservation and storage are summarized. As biological material some common fruits were chosen - green and red apples, peaches, plums and white grapes. The fruits were stored in laboratory, cellar, in refrigerator and in freezer. In freezing experiments some ways of fruit preparation and processing were tested and their influence on fruit antioxidant status was compared. Shortened storage experiment was applied on blueberries, cranberries, raspberries and strawberries too. In fruits some group parameters – total antioxidant status, dry mass content, ascorbate level, total flavonoids and total phenolics were analyzed spectrophotometrically. Individual flavonoids and phenolics were determined by RP-HPLC/UV-VIS and on-line LC/PDA/ESI-MS. Antioxidant enzyme activities (superoxide dismutase SOD, catalase CAT, polyphenol oxidase PPO and lipoxygenase LOX) were measured by spectrophotometry. The surface microscopy and cultivation of moulds from fruit surface were performed too. Influence of storage conditions on biological activities is dependent on fruit sort. Freezing is the most suitable procedure for long-term storage without significant changes of active substance content. Long-term storage in controlled temperature conditions and/or atmosphere is usable for fruits with longer storage period. In these fruits stabile levels of antioxidant enzymes are stored for relatively long time. Some of enzymes act synergistically. Enzyme activities differed according to storage phase; at the beginning mainly high SOD and LOX activities were observed. CAT and PPO are probably activated as defence systems in rippened and/or damaged fruits. Levels of total as well as individual low molecular weight antioxidants varied during storage in all sorts, generally, increased course with longer storage period can be observed.
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The possibilities electricity savings of refrigeration and cooling equipment according to the distribution rate - the cold storage
Pálka, Marek ; Šlezingr, Jan (referee) ; Macháček, Jan (advisor)
This bachelor´s thesis is focused on the possibilities of electricity savings of the freezing equipment, which would work only in low distribution rate and it would be disconnected from the power source in the high distribution rate. In this work, a total research in the field of refrigeration and cooling equipment, both technological circuits, as well as the principles of temperature regulation and food storage process is made. Another part of the work is focused on freezer testing standards and regulations. Much of the work is devoted to the experimental measurements, in which different types of rates on the given freezer equipment and with them associated the possibilities savings relative to other rates are measured. Another objective of the experimental measurement is to find out the temperature behaviour in the various parts of a freezing apparatus according to the switching time of the rates. There are overall experimental measurements evaluated and the possibility of electricity savings in direct reliance to the processes ongoing in the food during long term storage in the freezer in the unstable storage temperature In the conclusion of the work.
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The influence of various storage conditions on the stability of anthocyanins in blueberries (Vaccinium myrtillus L.)
Martanová, Anna ; Kotíková, Zora (advisor) ; Petr, Petr (referee)
This diploma thesis deals with the influence of different storage methods on the stability of anthocyanins in the fruits of blueberries. The theoretical part describes blueberry (Vaccinium myrtillus L.), anthocyanin pigments and their stability based on the studied literature. Moreover, an overview of the most common methods for their determination in plant materials is given. The methodical part depicts the methods of determining the content and the extent of the degradation of anthocyanins in blueberries using the different ways of storage. Anthocyanin dyes contained in the blueberries were subjected to acid hydrolysis and their content was expressed in the form of free aglycones (anthocyanidins). During the initial analysis, the measurement of the content of anthocyanidins in the fresh blueberries was done. Furthermore, a sample preparation was carried out applying the different storage methods. Three storage variants were tested, dried samples at 80 ° C, lyophilized and frozen samples. During the eight-month storage, five further measuring of the degradation rate of anthocyanins in time was performed. All samples were analyzed in triplicates. A mass spectrometer 3200 QTRAP with triple quadrupole and ESI ionization, coupled with a liquid chromatograph, type UHPLC was used for the analysis. Afterward, the values were averaged and presented using graphs and tables. The results of the thesis pointed out that the least intrusive variant of preserving the sample was lyophilisation, especially than for the first two months of storage. The amount of the anthocyanins did not changed during this period. Moreover, also the freezing variant was a suitable method for preserving the sample. Freezing was assessed as the favorable method for preserving the sample for longer periods since the value has decreased in the relation to time more gradually and during the final collection have shown higher values than the variant of the lyophilized blueberries. The variant of dried blueberries was the least stable compared to the previous variants. The rapid decline of anthocyanins occurred already during drying, depending on the time the values continued to decline In the variant of drying, petunidin was evaluated as the most stable anthocyanidin, while kyanidin and delphinidin were determined as the least stable. Delphinidin was determined to be the most stable anthocyanin in the variant of both freezing and lyophilization whilst the least stable the anthocyanins were petunidin in the variant of freezing and cyanidin in the variant of lyophilization.
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Microbial activity of deep subsurphace miocen sediments near Soklov
Galertová, Renata ; Frouz, Jan (advisor) ; Kryštůfek, Václav (referee)
In my diploma thesis I observed microbial activity in Miocene sediments collected at two different depths - 30 and 150 meters - in the "Družba" open-mine pit, which is located in Sokolov Brown Coal Basin. There were three different types of sediment: lamellar, amorphous and transitional. Samples were obtained under sterile conditions and following treatments were applied to the transitional sediment: addition of glucose, wetting and freezing. The aim of my study was to observe the activity of the original microflora at various depths and the impact of environmental factors that can affect the quarried claystones after being put on heaps. Microbial activity was evaluated by measuring released CO2 (titration). Obtained values of microbial activity did not show any differences between the respiration of sediments of different ages (depths), but differences between different types of sediments were significant, the highest values were found in lamellar sediment. Affection of samples then showed biota activity response suggesting that microbial communities at lower depths are limited by nutrients. Because the application of glucose did not show any noteworthy effect, we can assume that these communities are specialize on present fossil organic matter they are able to decompose, which is important especially in...
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The possibilities electricity savings of refrigeration and cooling equipment according to the distribution rate - the cold storage
Pálka, Marek ; Šlezingr, Jan (referee) ; Macháček, Jan (advisor)
This bachelor´s thesis is focused on the possibilities of electricity savings of the freezing equipment, which would work only in low distribution rate and it would be disconnected from the power source in the high distribution rate. In this work, a total research in the field of refrigeration and cooling equipment, both technological circuits, as well as the principles of temperature regulation and food storage process is made. Another part of the work is focused on freezer testing standards and regulations. Much of the work is devoted to the experimental measurements, in which different types of rates on the given freezer equipment and with them associated the possibilities savings relative to other rates are measured. Another objective of the experimental measurement is to find out the temperature behaviour in the various parts of a freezing apparatus according to the switching time of the rates. There are overall experimental measurements evaluated and the possibility of electricity savings in direct reliance to the processes ongoing in the food during long term storage in the freezer in the unstable storage temperature In the conclusion of the work.
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Influence of Storage Conditions on Metabolic Profile of Apples
Duroňová, Kateřina ; Vávrová, Milada (referee) ; Kráčmar, Stanislav (referee) ; Márová, Ivana (advisor)
The goal of presented dissertation has been complex analysis of changes in content of fatty acids, enzymatic and low-molecular antioxidants in apples and related evaluation of perception of originators of storage diseases for apples stored in various conditions. Main part of the work has been dedicated to study of the impact of storage of apples in modified atmosphere with reduced amount of oxygen and in reference “normal” atmosphere for six months. Next part of the work has been dedicated to study how apple storage in common, consumer affordable, conditions (storage in a cellar, in a refrigerator, and in room temperature) affects content of low-molecular antioxidants. For testing has been selected apple kinds Jonagored, Golden Delicious, Idared, Šampion, and Granny Smith. Within the scope of this work has been optimized the method for determination of fatty acids in plant material with higher content of wax. The measured values imply the apples are valuable source of many important nutrition substances like vitamins, provitamins and antioxidants. During the storage process these substances exhibit considerable protective function. Long-term storage, mainly in the atmosphere with reduced amount of oxygen (FAN), enables preservation of majority of these important nutrition substances depending on the kind of apple and conditions of storage. Freezing process is conservative to apples (mainly in the presence of protective substances), while in the process of drying the values of all monitored antioxidants decrease depending on temperature and conditions of drying. Upon the choice of the storage method one must consider nutrition, sensoric characteristic and consumer demands.
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Changes in selected local fruits during freezing.
Matějková, Markéta ; Melounová, Jitka (referee) ; Márová, Ivana (advisor)
This diploma thesis was focused on study of low-molecular antioxidants present in various kinds of fruits, namely berries. In theoretical part detailed characterization of antioxidants studied in presented work and their biological effects are introduced. Further, principals of processing and storage of specified species of fruits are discussed. Changes observed during storage of specific fruits are described too. In practical part changes in content of selected antioxidants in berries were followed. As studied material strawberries, raspberries, blueberries, red and black currants were used. All kind of these fruits was stored in fridge for six months using several different kind of processing. Berries were stored as whole fruits, whole osmotically processed fruits by sucrose, raw pulp and sweetened pulp. At first, starting values of selected antioxidant parameters were measured in fresh fruits (ascorbate, total antioxidant activity, total phenolics, catechins and individual flavonoids). After freezing the same parameters were measured regularly in two month periods. As the most suitable method of fruit processing, with regard to antioxidant content, storage of the whole fruits or pulp can be recommended. Content of ascorbate decreased in all forms and species of the processed fruits during all the time of storage. Oppositely, the content of other studied antioxidants exhibited fluctuations or increasing trend. Sensory analysis was proved for the whole fruits and also for whole sweetened fruits.
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