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Extraction of bioactive substances from the pomace of red grapes
Jandrtová, Sabina ; Pořízka, Jaromír (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis deals with the research of chosen chemical characteristics in juice and in extracts of grapevine (Vitis vinifera L.). The theoretical part is divided into three parts. In the first part is described the botanical characteristic of grapevine, then its origin, morphology, chemical composition, species and uses. In the second part are characterized anthocyanin pigments, their occurrence and attributes. There are described methods of the investigation. In the third part are described extractions. The experimental part illustrates extractions of the pomace. The purpose of these extractions is to find out the total amount of anthocyanins and phenolics in the pomace, and which solvent gives the highest yield. Then the chemical characteristics, such as total and soluble solids, pH, the amount of titratable acids, reducing carbohydrates, phenolics and anthocyanins, are described in this section. All determinations are executed and results are compared among grapevine juice and two species (Cabernet Sauvignon and Zweigeltrebe). The most suitable solvent is selected a mixture of water and ethanol in a ratio 50:50. In the most effective hours are determined the chemical characteristics. The titratable acids are expressed as the amount of the tartaric acid. The amount of phenolics is expressed as gallic acid and the amount of anthocyanins as malvidin-3-glucoside.
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Extraction of bioactive substances from black currant pomace
Sedláčková, Lucie ; Štursa, Václav (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis deals with extraction of bioactive substances from black currant pomace (Ribes nigrum). The theoretical part contains the botanical characteristics of the plant species Ribes nigrum. It is also devoted to the biologically active substances contained in black currant and possibilities of using black currant in the food industry. The fourth chapter deals with description of phenolic compounds, their distribution and methods of determination of phenolic substances. The fifth chapter describes selected extraction procedures. In the experimental part, there were extracted dry black currant pomace in order to optimize the extraction process and obtain the highest yields of dyes. In addition, were determined the selected chemical and physical characteristics of blackcurrant juice and extracts from blackcurrant pomace. A better solvent was a mixture of water and ethanol in a volume ratio of 1:1. After 14 hours maceration of dry pomace, were obtained 769,9 mg anthocyanins per 100 g of dry material.
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Chemical characteristics of fruit Mirabelle plum
Lukšová, Leona ; Pořízka, Jaromír (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis deals with chemical and physical analysis of dried, lyophilized and stewed fruit, specially Mirabelle de Nancy. Theoretical part is devoted to the origin, the economic importance of plums, the botanical classification of Mirabelle de Nancy and other subspecies belonging to the genus Prunus. Subsequently the most economical method of preserving food called lyophilization is described. Part of this work is also the theme of raw food and description of biologically active substances contained in this fruit. In the experimental part, these characteristics of Mirabelle de Nancy were analyzed: total solids, soluble solids, determination of reducing sugars, titratable acidity, phenolic substances and ascorbic acid. It has been found that the lyophilized friut contains 16,8 wt. % of reducing sugars which is less than dried fruit with a value of 18,0; wt. %. It also contains less titratable acids with a value of 59,7 mmol/l versus 72,7 mmol/l in dried fruit.
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Extraction of bioactive substances from black chokeberry pomace
Kapiton, Ulyana ; Veselá, Mária (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis deals with the quantification of selected bioactive substances in chokeberry juices, in the extracts of chokeberry and in chokeberry tea. In the theoretical part, there is a botanical description of chokeberry, (Aronia melanocarpa). Furthermore, the chemical properties of aronia and their use in the food, cosmetics industry and in the medicine. At the end of the theoretical part there are presented manual methods for determination of simple saccharides and briefly described selected extraction methods. The experimental part contains the determination of these chemical characteristics of analyzed aronia products: pH, titratable acidity, refractometric determination of dry matter, reducing sugars according to Bertrand's method and gravimetric determination, total phenolics and total anthocyanins. The highest phenolic content 319,54 mg·dm-3 were determined in a sample of aronia tea for 10 min digestion. The highest concentration of anthocyanin dyes was also determined in this tea – 889,49 mg·dm-3.
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Study of extraction of the biologically active substances from elderberry marc
Lošková, Tereza ; Diviš, Pavel (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis deals with the determining of anthocyanin pigments in the extracts of elderberry marc (Sambucus nigra L.). The theoretical part is divided into four main chapters. In the first chapter there is botanical characteristics of elderberry, its origin and occurrence, chemical composition and the possibilities of usage in a food industry. The second part is devoted to characterization of phenolic compounds in berry fruits. Bigger attention is given to anthocyanin dyes, its occurrence, properties, health and antioxidant effects and the possibilities of usage in food industry. The third chapter is devoted to methods of determination of discussed dyes and phenolic compounds. The fourth chapter deals with the possibilities of disruption of plant cell walls. In the experimental part a series of elderberry marc's extraction was made. The purpose was to optimize the extraction course and to get the highest yield of dyes in an economically and operationally acceptable way. Time dependence of extractions was studied and a kind of extraction solvent and a ratio of its components were optimized. Distilled water or its mixture with ethanol was used as a solvent. During the water extraction the temperatures 25 °C and 50 °C were maintained and with the higher temperature the higher yields were obtained. Apart from this another supporting components as cellulolytic enzyme, ultrasound or shaker were used. The most effective method of extraction proved to be the extraction by the mixture water-ethanol (50:50) in the volume 80 mL. The total anthocyanins yield of this extraction was, expressed as cyanidin-3-glucoside equivalent, 914,4 ± 3,8 mg100 g-1 dry weight after 10 hours and the total phenolics yield was, expressed as gallic acid equivalent, 1957,0 ± 9,9 mg100 g-1 dry weight at the same time. The usage of ultrasound increased the efficiency of the extraction by water at 50 °C by 12 %. On the contrary, the usage of cellulolytic enzyme didn't increase the anthocyanin yield, because the enzyme was inactive.
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Selected nutritional parameters of some lesser known fruit
Diblíková, Michaela ; Hrstka, Miroslav (referee) ; Vespalcová, Milena (advisor)
Diploma thesis is focused on the chemical analysis of the juices of black, red and white currant and jostaberry (Ribes a Ribes x culverwellii). The theoretical part is focused to the definition of fruit, fruit importance in human nutrition, description of Ribes and Ribes x culverwellii genuses, active substances in the currants and the jostaberry, description of selected chemical parameters and the determination of some of them. The procedures of determining for the following chemical parameters are described in the experimental section: determination of reducing sugars, determination of total and soluble solids, formol number, pH, titratable acidity, determination of total phenols and anthocyanins and determination of vitamin C in two samples jostaberry, six varieties of black currants, one variety of white currant and two varieties of red currants. Based on the evaluation of the obtained results, the comparison was made with different varieties and the thesis that "overall comparison of the different varieties in the content of phenolic compounds, vitamin C and anthocyanins appears to be the most promising variety of blackcurrant demon. It should however be noted that the highest content of phenolics and anthocyanins were determined in jostaberry„ has been suggested.
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Antioxidative substances in selected fruit and herbal teas
Tomková, Martina ; Buňková, Radka (referee) ; Márová, Ivana (advisor)
This diploma project deals with antioxidant and antimutagenic properties of selected herbal and fruit teas commonly used in Czech population. Influence of different tea packaging (bag teas and loose leaf teas) on bioactive compound content was compared. Further, effect of long-term storage in common household conditions was studied. Antioxidant properties of teas were characterized using some group parameters - total antioxidant activity ("Randox Total Antioxidant Status Kit"), total phenolics and total flavonoids - as well as some individual representatives of low molecular weight antioxidants. Higher antixidant content was found in herbal teas than in fruit teas. Comparing bag teas with loose leaf teas higher antioxidant activity was shown in loose leaf teas. Individual antioxidants were analyzed using HPLC method with spectrophotometric detection and verified by on-line LC/MS. IN all tea samples catechins - catechin, epicatechin, epicatechin gallate and other flavonoids - rutin, morin, quercetin, kaempferol, myricetin and luteolin were determined. In most of teas high level of catechin and rutin was detected. The highest level of flavonoids was determined in herbal poured teas. Ascorbic acid content was also determined by HPLC method. Higher vitamine C level was found in most of fruit teas and in rose hip tea. Antimutagenicity of tea extracts was tested by in vitro test using Saccharomyces cerevisiae D7 yeast. High antimutagenic activity showed mainly nettle tea, tutsan tea and most of fruit teas. During long-term storage (1 year, 20°C, darkness) a significant decrease of all analyzed antioxidant parameters was followed. Higher lost of antioxidants was found in fruit teas when compared with the herbal ones.
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Biologically significant substances in cereal products
Vondráčková, Hedvika ; Halienová, Andrea (referee) ; Márová, Ivana (advisor)
Presented work was focused on study of biologically significant substances in cereal products. In experimental part selected active substances in cereal bars were analyzed. The highest content of total phenolics, total flavonoids, total antioxidant capacity, procyanidin B2 and chlorogenic acid was measured in plums and blueberry bars. The highest level of reduced saccharides was evaluated in raspberry and cereal bars. Presence of main simple sugars - maltose, glucose and fructose was detected in all bar samples.
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